magnetospheres of the outer planets -...
TRANSCRIPT
![Page 1: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/1.jpg)
Magnetospheres of the Outer Planets
2018 Conference
July 8 - 13, 2018
University of Colorado Boulder Boulder, Colorado, USA
Sponsored by:
European Space Agency
Laboratory for Atmospheric and Space Physics
Southwest Research Institute
1
![Page 2: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/2.jpg)
We thank sponsors of 2018 Magnetospheres of the Outer Planets Conference:
Laboratory for Atmospheric & Space Physics, University of Colorado European Space Agency
Southwest Research Institute, Boulder Colorado We thank the following for making the meeting happen: MOP2018 Scientific Organizing Committee Fran Bagenal, Chair Carol Paty Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki Fujimoto Frank Crary Joachim Saur Xianzhe Jia Chihiro Tao Joe Westlake Olivier Witasse John Clarke Tom Stallard Philippe Zarka Norbert Krupp MOP2018 Local Organizing Committee Fran Bagenal – The Boss Rob Wilson Andrew Steffl LASP Event Staff Anca Kokinakos Anastasia Bailey Louise Krieger Chris Crouch MOP2018 Student Helpers – The MOPsters Grace Marshall Jon Lutz Amanda Swain Parker Hinton Eddie Nerney
2
![Page 3: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/3.jpg)
Agenda
Sunday, July 8th
6:00-9:00p Reception Rayback Collective: 2775 Valmont Rd, Boulder, CO 80304
Monday, July 9thInvited Talks: 25 minutes Contributed Talks: 15 minutes Abstract Page #
9:00 IntroductionChair: Michele Dougherty
9:10 Thomsen, M.F. Magnetospheric Structure and Dynamics at Saturn (and maybe Jupiter) 1019:35 Connerney, J.E.P. A Degree 10 Spherical Harmonic Model of Jupiter’s Magnetic Field
from the Juno Magnetometer Investigation 299:50 Cao, H Saturn’s Internal Magnetic Field Revealed by Cassini Grand Finale 2310:05 Khurana, K.K. Discovery of Atmospheric-Wind-Driven Electric Currents in Saturn’s
Magnetosphere in the Gap between Saturn and its Rings 5610:30 Break
Chair: Carol Paty11:00 Masters, A. The magnetospheres of Uranus and Neptune 7011:25 Griton, L. A Uranus-like magnetosphere in a magnetized Solar Wind: solstice and
equinox configurations 3811:40 Kivelson, M.G. Mass transport at Jupiter and Saturn 5812:05 Delamere, P.A. Entropy constraints on radial transport in the giant planet magnetospheres 3212:30 Lunch
Chair: Peter Delamere2:00 Vasyliunas, V.M. Outflow of plasma without removal of magnetic flux: What is the real
magnetic topology? 1032:15 Badman, S.V. Saturn’s auroral processes: insights from the Cassini Grand Finale 152:40 Burkholder, B.L. Quantifying Kelvin-Helmholtz driven variability of plasma conditions
near Saturn's magnetopause boundary 222:55 Kinrade, J. Analysing Cassini UVIS & INCA imagery during injection events at Saturn:
an inverse problem 573:15 Break
Chair: Abi Rymer4:00 Southwood, D.J. Saturnian planetary period oscillations, angular momentum transfer and
plasma sub-corotation 97Given by: Hunt, G.J.
4:15 Bradley, T.J. Planetary period modulations of reconnection events in Saturn’s magnetotail 204:30 Provan, G. Will we ever know the time on Saturn? Saturn’s Planetary Period
Oscillations observed throughout the Cassini mission. 854:45 Azari, A. R. Are Saturn’s Interchange Injections Organized by Rotation Longitude? 14
Tuesday, July 10th8:55 Announcements
Chair: Nick Achilleos9:00 Yates, J.N. 3D Jovian Magnetosphere - Ionosphere - Thermosphere (MIT) 1089:15 O'Donoghue, J. The atmospheric consequences of mid-latitude magnetosphere-ionosphere
coupling at Saturn 809:30 Allen, R.C. Internal versus external sources of plasma at Saturn: Overview from
MIMI/CHEMS data 129:45 Mitchell, D.G. D-Ring Dust Falling into Saturn’s Equatorial Upper Atmosphere 7310:00 Hsu, H.-W. Cosmic Dust Analyzer onboard Cassini Collects Material from Saturn’s
Main Rings 4710:15 Hadid, L. Z. Saturn’s ionosphere: Electron density altitude profiles and ring
shadowing effects from the Cassini Grand Finale 4010:30 Break
Chair: Barry Mauk11:00 Cravens, T. E. The Ion Composition and Dynamics of Saturn’s Equatorial Ionosphere
as Observed by Cassini 30
3
![Page 4: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/4.jpg)
11:15 Cassidy, T.M. Comparative Modeling of the Magnetosphere of Saturn and Jupiter 2511:30 Becker, H.N. Jupiter’s high energy particle environment at high latitudes: observations
from Juno’s Radiation Monitoring Investigation 1711:55 Santos-Costa, D. Results from 2 years of high time-space sampling of Jupiter’s radiation
with JUNO/MWR 9112:10 Haggerty, D. K. Charged particle injections at high Jovian latitudes 4012:30 Lunch
Chair: Gabby Provan2:00 Kollmann, P. The ion radiation belts of Jupiter and Saturn 612:25 Kim, T.K. Ion Properties of Jupiter's Plasma Sheet: Juno JADE-I Observations 562:40 Lamy, L. A brief overview of auroral processes on Uranus and Neptune 643:05 Smith, H.T. Confirming and constraining the presence of a Europa-generated neutral
(asymmetric) torus 953:20 Break
Posters: Session APoster # Author Title
1 Arridge, C.S. Neutral tori in Neptune’s magnetosphere 142 Bergman, J. Radio & Plasma Wave Investigation (RPWI) for JUpiter ICy moons
Explorer (JUICE) – Langmuir probe investigations 183 Ebert, R. W. JUpiter MagnetosPheric boundary ExploreR (JUMPER) 354 Imai, K. CubeSat project for Jupiter's radio science 495 Kasaba, Y. High Frequency part in Radio & Plasma Wave Investigation (RPWI)
aboard JUICE: Toward the investigation of Jupiter and Icy Moons System 556 Bagenal, F. Is Jupiter a colossal comet? Will Juno decide? 168 Huscher, Ezra Plasma sheet properties observed by Juno at Jupiter 489 Krupp, N. Future Jovian Magnetospheric science with JUICE 63
10 Lee-Payne, Z Correcting Galileo’s Energetic Particle Detector (EPD) data; Methodology and Implications. 65
11 Lorch, C An investigation into radial and azimuthal currents in Jupiter's Magnetodisc 6612 Manners, H. Standing Alfvén waves in Jupiter's magnetosphere as a source of ~10-60
minute quasi-periodic pulsations 6913 Nakamura, Y. Study of the Jovian magnetosphere-ionosphere coupling using an
ionospheric potential solver: Contributions of H+ and meteoric ions to ionospheric conductivity 77
14 Ranquist, D.A. Properties of Jupiter's Dawn Magnetosheath as Measured by Juno and New Estimate of the Polar Flattening of Jupiter's Magnetosphere 86
15 Sarkango, Y. Response of Jupiter's magnetosphere to varying solar wind conditions: Insights from global MHD simulations 92
16 Valek, P. W. The Jovian Ionospheric ion population observed by Juno's JADE instrument 10317 Vogt, M. F. Juno Observations of Magnetotail Reconnection at Jupiter 10418 Wilson, R.J. Forward Modeling Multiple Heavy Ion Species in JADE Data 10719 Yoshioka, K. Plasma and energy transport in Jupiter’s inner magnetosphere as deduced
from Hisaki observation 10920 Alexeev, I.I. Contributions of the Ionospheric Hall Currents to the Jupiter's and Saturn's
Magnetic Field 1121 Horanyi, M. Charged Dust Dynamics at Jupiter and Saturn 4522 Kivelson, M. G. Heating Jupiter’s plasma torus (Saturn’s too) through interchange 5923 Guio, P. Effects of the Size Scale on the Dynamics of Trapped Charged Particles
in Gas Giant Magnetospheres 3924 Masters, A. A more viscous-like solar wind interaction with all the giant planets? 7125 Pontius, D.H. Consequences of non-conformal magnetic field mapping 8426 Sakanoi, T. Planetary and exoplanetary observations with the Haleakala telescopes
and a future 1.8-m off-axis telescope project PLANETS 9127 Agiwal, O. Modelling the structure of Saturn's nightside current sheet during
Cassini's F-ring apoapsis passes 1128 Andrews, D.J. Equatorial magnetic field oscillations observed over the Cassini mission 1329 Bader, A. Statistical planetary period oscillation signatures in Saturn’s UV auroras 1530 Bunce, E.J. Observations of Saturn’s Ring Current during the Cassini Grand Finale Orbits 2131 Chané, E. Global MHD simulations of Saturn's magnetosphere 2632 Davies, E.H. Transient Configurations of Saturn’s Dayside High Latitude Magnetic Field 3133 Farrell, W.M. Saturn’s Plasma Density Depletions Along Magnetic Field Lines Connected
to the Main Rings 36
4
![Page 5: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/5.jpg)
34 Hamil, O.Q. The significance of Saturn ring-ice in Cassini proximal observations. 4135 Hardy, F. Towards a self-regulating magnetopause model with application to Saturn 4136 Hendrix, A. R. Cassini UVIS detects energetic electrons and dust in the Saturn system 4237 Hunt, G. J Field-aligned currents from the F-ring orbits of Cassini 48
38a Jasinski, J. M. Plasma observations at Saturn’s high-latitude magnetosphere and cusp 5138b Jasinski, J. M. Suvery of Electron measurements at Saturn's Magnetosphere using
CAPS-ELS 5239 Jia, X. Coupled Fluid-kinetic Global Simulations of Saturn's Magnetopause Dynamics 5240 Kane, M. Cassini Mission-wide Analysis of Hot Ions Detected by the INCA and
CHEMS Instruments in the Magnetosphere of Saturn 5441 Martin, C. J. Current density in Saturn’s Equatorial Current Sheet 6942 Menietti, J. D. Anomalous Plasma Waves Observed During Cassini's Ring-grazing Orbits 7243 Misawa, H. Identification of Jupiter's hectometric radiation associated with reconnection
in the magnesphere 7244 Morooka, M.W. Saturn’s Dusty Ionosphere 7445 Neupane, B. Transport and Turbulent Heating in Saturn’s Magnetosphere. 7946 Parunakian, D.A. Open and partially closed models of solar wind interaction with Saturn's
magnetosphere 8147 Perry, M. E. Relative fractions of water-group ions in Saturn’s inner magnetosphere 8248 Píša, D. Electrostatic solitary waves observed during Cassini's ring-grazing and
Grand Finale orbits 8349 Ponce, I.D. Rotation of the Interplanetary Magnetic Field in Saturn's Magnetosheath 8350 Roussos, E. Sources, sinks and transport of energetic electrons near Saturn's main rings 8951 Sawyer, R.P. An Investigation of Suppression of Magnetic Reconnection at Saturn’s
Magnetopause 9352 Sergis, N. Distribution of hot ion plasma in Saturn’s middle magnetosphere, from
>13 years of Cassini orbits 9453 Sorba, A. M. Investigating how the large-scale structure of Saturn’s magnetosphere
varies with local time using a combined data and modeling approach 9654 Staniland, N.R. Quantifying the stress of Saturn's magnetosphere during the entire
Cassini mission 9855 Stephens, G.K. A new empirical magnetic field model for Saturn's magnetosphere 9956 Vriesema, J. W. Electrodynamics in Saturn's Thermosphere 10457 Wahlund, J.-E. On the Characteristics of Charged Dust in Saturn’s Equatorial Ionosphere –
Implications from Cassini RPWS/LP data 10558 Woodfield, E.E. The effect of wave particle interactions on electrons close to Saturn 10859 Cao, X. Diurnal and Seasonal Variability of Ice Giant Magnetospheres under
Different IMF Conditions 2360 Wang, L. Self-consistent modeling of planetary electron dynamics 10561 Carlton, A.K. Using the Galileo Solid-State Imaging Instrument as a Sensor of Jovian
Energetic Electrons 2462 Collier, M.R. A K-means Clustering Approach to the Number of States of the Jovian
and Terrestrial Magnetopauses 2863 Kammer, J.A. Juno-UVS Measurements of High-Energy Radiation at Jupiter 5364 Nenon, Q. What has been learnt about the radiation belts of Jupiter with the physical
model Salammbô 7865 Soto-Chavez, R. Generation of ULF waves by the Drift-Mirror Plasma Instability 97
5
![Page 6: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/6.jpg)
Wednesday, July 11th8.55 Announcements9:00 Next Meeting
Chair: Marissa Vogt9:25 Palmaerts, B. Auroral storm and polar arcs at Saturn – Final Cassini/UVIS auroral
observations 809:40 Murakami, G. Response of Jupiter's inner magnetosphere to solar wind derived from
Hisaki and Juno/JADE observations 7610:05 Gladstone, G.R. Jupiter's Ultraviolet Auroras 3810:30 Break
Chair: Emma Bunce11:00 Grodent, D. Jupiter’s mesmerizing auroral show; HST ultraviolet observations near
and far from Juno perijoves 3911:15 Nichols, J. D. Jupiter’s mesmerizing auroral show; HST ultraviolet observations near
and far from Juno perijoves 7911:30 Bonfond, B. The polar region of Jupiter’s aurora : barcode noise, conjugate flares
and more… 2011:45 Kita, H. EUV aurora’s response to solar wind measured with Hisaki & Juno 5812:10 Clarke, J.T. Thoughts on the Production of Jupiter’s Aurora 2712:30 Lunch
2:00 Free Time
6:00-9:00 Banquet
Thursday, July 12th8:55 Announcements
Chair: Licia Ray9:00 Mura, A. Juno/JIRAM observations of Jupiter’s main aurorae and satellite footprints. 759:25 Clark, G Megavolt potentials over Jupiter’s polar cap region 269:40 Cecconi, B. Physics and Observations of auroral radio emissions at Jupiter and Saturn 2510:05 Elliott, S.S. A two-step mechanism for accelerating up-going electrons throughout
Jupiter’s polar cap region via interactions with up-going whistler-mode waves 3610:30 Break
Chair: Jamey Szalay11:00 Dunn, W. R. Jupiter’s X-ray Aurora Spectra 2016-2017 3311:25 Rymer, A.M. Juno observations of energetic charged particles associated with
Jupiter’s aurora. 9011:40 Ebert, R. W. Comparing Electron Energetics and UV Brightness in Jupiter’s Polar
Auroral Region 3511:55 Mauk, B. H. Auroral acceleration at Jupiter and its possible role in creating Jupiter’s
uniquely energetic radiation belts 7112:30 Lunch
Chair: Joe Westlake2:00 Allegrini, F. Energy flux of precipitating electrons over Jupiter’s main auroral emission 122:15 Damiano, P.A. Kinetic simulations of electron acceleration by dispersive scale Alfven
waves in the Jupiter magnetosphere 312:30 Saur, J. Wave-Particle Interaction in Jupiter's Magnetosphere: Auroral and
Magnetospheric Particle Acceleration 922:45 Lysak, R. L. Alfvenic Aurora at Earth and Jupiter 683:00 Kurth, W.S. Novel Electron Distribution Functions Associated with a Source of
Broadband Kilometric Radiation at Jupiter 633:30 Break
6
![Page 7: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/7.jpg)
Posters: Session BPoster # Author Title
1 Dunn, W. R. Jupiter's X-ray Aurora During Solar Minimum 342 Higgins, C. Radio Jove Citizen Science Partnerships 433 Higgins, C. LWA1 Observations of Jupiter’s Left-Hand Polarized Decametric Emission 444 Houston, S.J. Modeling of Jovian Auroral Polar Ion and Proton Precipitation 465 Hue, V. Juno-UVS observation of the Io footprint 47
6Imai, K. Frequency dependence on the beaming angle of Jupiter's decametric
radio emissions 50
7Imai, M. Stereoscopic observations of Jovian decametric radio arcs associated
with ultraviolet auroras 50
8Gérard, J.-C. Combined Juno observations and modeling of the Jovian auroral electron
interaction with the Jovian upper atmosphere 37
9Jackman, C.M. Assessing quasi-periodicities in Jovian X-ray emissions: techniques and
heritage survey 51
10Kimura, T. Response of Jupiter's Aurora to Plasma Mass Loading Rate Monitored
by the Hisaki Satellite During Volcanic Eruptions at Io 57
11Louarn, P. On the saturation mechanisms of the cyclotron maser instability - An
investigation with Juno 6712 Louis, C. Jupiter auroral emissions : statistical distibution of radio sources 6713 Magalhaes, F.P. Long-term variations and correlations of Jovian radio components 6814 Ray, L.C. Characterising Jupiter's Auroral Acceleration Region 87
15Rutala, M.J. Characterizing Local and Interplanetary Control of Jupiter's Auroral
Dawn Storms using HST and Juno 90
16Sinclair, J. A. Gemini-TEXES mid-infrared spectral observations of Jupiter’s auroral
regions: comparison with ultraviolet and near-infrared observations 9517 Song, Y. Towards Unified Theory of Auroral Particle Acceleration at Earth and Jupiter 96
18Tao, C. Volcanic Control of Jupiter's Aurora and Middle Magnetosphere Dynamics
Observed by Hisaki/EXCEED and Analysis Improvements by Juno 10119 Trafton, L.M. Auroral Excitation Along Open Jovian Magnetospheric Field Lines 102
20Watanabe, H. Pulsation characteristics of Jovian infrared polar aurora observed by
Subaru IRCS with adaptive optics during Juno’s solar wind campaign 10621 Fischer, G. SKR: A rotating radio source that appears clock-like 3722 Lamy, L. The low frequency source of Saturn’s Kilometric Radiation 64
23Nakamura, Y. Long-term variation of the North–South asymmetry in the intensity of
Saturn Kilometric Radiation (SKR) in 2004-2017 76
24Prangé, R. Saturn’s northern aurorae at solstice from HST observations coordinated
with Cassini’s Grand Finale 8525 Pryor, W.R. Cassini UVIS Observations of Saturn's Auroras and Polar Haze 86
26Ye, S.-Y. An SLS5 longitude system based on the rotational modulation of Saturn
radio emissions 109
27Berland, C Analysis of HST, VLT and Gemini recent observations of Uranus at
UV/IR wavelengths 1828 Roth, L. HST Lyman-alpha observations of Uranus 8929 Liuzzo, L. Energetic ion dynamics near Callisto 65
30Liuzzo, L. A comprehensive picture of Callisto's magnetic and cold plasma
environment during the Galileo era: Implications for JUICE 6631 Crary, F. J. Energetci neutrals from the Europa interaction: Finite gyroradius effects 29
32Heuer, S.V. Investigating Deflection of Jovian Bulk Plasma by Europa’s Ionosphere
using Galileo Plasma Data 4333 Huybrighs, H.L.F. Signatures of Europa’s atmosphere in Galileo EPD data during the E12 flyby 4934 Korth, H. Fields and Particles Investigations by the Europa Clipper Mission 6235 Spencer, J. R. Spatial Distribution of Condensed Oxygen on Europa 9836 Bard, C. Simulating Ganymede's Magnetosphere with Graphics Processing Units 17
37Carnielli, G. Constraining Ganymede’s neutral and plasma environment through
numerical simulations of its ionosphere 24
38
Collinson, G.A. New results from Galileo's first flyby of Ganymede: Reconnection driven flows at the low-latitude magnetopause boundary, crossing the cusp, and icy ionospheric escape 28
39Zhou, H. Magnetopause Dynamics from 3D Hall MHD-EPIC Simulations of
Ganymede`s Magnetosphere 110
40Arakawa, R. Longitudinal variations of the sulfur ions in the Io plasma torus observed
by the HISAKI/EXCEED 1341 Coffin, D. A. The effect of subcorotation on Jupiter's System IV periodicity 27
7
![Page 8: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/8.jpg)
42Hikida, R. Variation in composition and temperature of plasmas in the Io plasma
torus confirmed by the Hisaki/EXCEED observation 4443 Hinton, P. A 4D Model of the Io Plasma Torus 45
44Koga, R. Spatial distribution of atomic oxygen emissions around Io's orbit during
volcanically quiet and active periods 60
45Morgenthaler, J.P. Observations of the Jovian sodium nebula and Io plasma torus with the
Io Input/Output Facility (IoIO) 73
46Nerney, E.G. Constraining Plasma Conditions of the IPT via Spectral Analysis of UV
& Visible Emissions and Comparing with a Physical Chemistry Model 7847 Phipps, P.H. Io plasma torus geometry from Juno radio occultations 8248 Rathbun, J. A. Io Volcano Monitoring from the IRTF in Support of Juno and Hisaki 8749 Schmidt, C.A. Visible Wavelength Spectroscopy of the Io Torus During the Hisaki Mission 9350 Schneider, N.M A Search for Ion Scale Height Variability in Hisaki Io Torus Observations 94
51Wannawichian, S. Angular Size of Io Magnetic Footprint’s Main Alfvèn Wing Spot: In
Corresponding to Satellite’s Locations 10652 Dols, V. Atmospheric loss at Io, Europa; massloading and ion cyclotron waves production 3253 Bagenal, F. Flow of Mass and Energy Through the Io-Europa Space Environment 1654 Travnicek, P. Multi-species hybrid modeling of plasma interactions at Galilean moons 10256 Crary, F. J. Magnetic induction signatures from an ocean within Triton 3057 Paty, C. The magnetospheric interaction between Neptune and Triton 81
58Katoh, Y. Software-type Wave-Particle Interaction Analyzer (S-WPIA) by RPWI
for JUICE 55
59Munoz, J., Jr. Obstruction of Low Energy Electron Trajectories to JADE-E Due to
Jupiter’s Strong Magnetic Field and its Effect on Pitch Angle Measurements 7460 Brown, L.E. Visualizing Data from Cassini, JUNO, and More Using HAPI, Autoplot, and MIDL 2161 Burton, M.E. Cassini Magnetospheric Science Discipline End-of-Mission PDS Data Products 2262 Koskinen, T.T. Saturn’s thermosphere from Cassini/UVIS Grand Finale stellar occultations 62
Friday, July 13th8:55 Announcements
Chair: Amanda Hendrix9:00 Sulaiman, A.H. Auroral hiss emissions during Cassini’s Grand Finale: Diverse
electrodynamic coupling between Saturn, its rings, and Enceladus 1009:15 Hospodarsky, G.B. Juno Observations of Plasma Waves Associated with the Io Footprint Tail 469:30 Szalay, J. R. Juno Observations Connected to the Io Footprint Tail Aurora 1009:45 Roth, L. Io and Europa: Influence of volcanic outbursts, moon-footprint
connections and plume activity. 8810:10 Retherford, K.D. HST Mid-Cycle 25 Europa Campaigns: New Approaches to Constrain
Plume Abundance, Composition, and Variability 8810:30 Break
Chair: Melissa McGrath11:00 Jia, X. Evidence of a Plume on Europa from Galileo Magnetic Field and
Plasma Wave Signatures 5311:15 Blöcker, A. Alfvén winglets due to plumes on Europa and Io 1911:30 Harris, C.D.K. Quantifying the access of Jupiter’s magnetospheric plasma to Europa’s
surface through a multi-fluid MHD model 4211:45 Poppe, A.R. Thermal and energetic ion dynamics in Ganymede's magnetosphere 8412:00 Liuzzo, L. Energetic ion dynamics near Callisto 6512:15 Zarka, P. Jupiter radio emission induced by Ganymede and consequences for
the radio detection of exoplanets 11012:30 Lunch
Chair: Frank Crary2:00 Bertucci, C. Titan's plasma interaction 192:25 Martin, C.J. Statistical Analysis of Flux Ropes in Titan’s Ionosphere: A comparison
of force-free and non-force-free methods 702:40 Westlake, J.H. A Compendium of the Saturn-Titan Interaction as Observed with
Energetic Neutral Atoms (ENAs) from Cassini MIMI-INCA 1073:00 Break
8
![Page 9: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/9.jpg)
Abstracts
9
![Page 10: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/10.jpg)
10
![Page 11: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/11.jpg)
ModellingthestructureofSaturn'snightsidecurrentsheetduringCassini'sF-ringapoapsispassesAgiwal,O.,ImperialCollegeLondonDougherty,M.K.,Hunt,G.J.,Provan,G.,Cowley,S.W.H.
TheCassinispacecraftconducted20F-ringorbitsduringnorthernsummeratSaturn.Theorbits’apoapsispassescorrespondtothespacecraftcrossingSaturn’snightsidecurrentsheet.Thecrossingofthecurrentsheetisidentifiedbyareversalintheradialcomponentofthemagneticfield.Observationsshowthatthenatureofthisreversaldiffersfromorbittoorbit,despitetheirsimilartrajectories.CrossingsareobservedatarangeofpositionsaboveandbelowtheexpectedmagneticequatorinSaturn’smagnetotail,withsomecasesevenshowingmultiplereversalsduringthesameorbit.Weconsideramodelwhichcombinestheperturbationeffectsofthenorthernandsouthernplanetaryperiodoscillation(PPO)systemsonSaturn’shingedmagnetotailcurrentsheet.Dependingontherelativephasebetweenthetwosystems,thecurrentsheetundergoesacombinationofthicknessmodulationsandnorth-southdisplacements.For12F-ringorbits,themodeloffersaplausibledescriptionforthedifferenttypesofcrossingsobservedinthemagneticfielddata.ItalsoconfirmsthatthesecrossingsoccurinaregimewherethenorthernPPOsystemdominatesthesouthern,aswouldbeexpectedfornorthernsummeratSaturn.ContributionsofionosphericHallcurrentstoJupiter’sandSaturn’smagneticfieldAlexeev,I.I.,FederalStateBudgetEducationalInstitutionofHigherEducationM.V.LomonosovMoscowStateUniversity,SkobeltsynInstituteofNuclearPhysics,RussianFederationLavruchin,A.S.,ParunakianD.A.
Magnetosphere-ionosphereinteractionsincaseofrapidlyrotatingplanetswithanadditionalsourceofinter-magnetosphericplasma(JupiterandSaturn)resultsintothemagnetosphericplasmabeingunabletorigidlycorotatewiththeplanet.Slippingofthemagnetosphericplasmaresultsintogenerationoftheequatorialplasmamagnetodiscwithembeddedstrongazimuthalcurrents.IncaseofJupiterthismechanismresultsintoaneffectiveplanetarydipoleenhancementbyafactorofabout2-3.Thesameprocessresultsintogenerationofapotentialdropalongmagneticfieldlines,aswellaselectronsbeamaccelerationandpowerfulauroraemissionsintheupperatmosphere.Theveryhighfield-alignedconductivityrequiresmagneticfieldlinestobeequipotential(parallelelectricfieldmustbezero)andangularvelocitytobethesameattheionosphereandintheequatorialplane,butbeyondtheAlfvenicradiusmagneticfieldcannotcontroltheplasmaflowinthemagnetosphere,andaspecific3Dcurrentsystemisgenerated.Theionosphericpartofthetotalcurrentsystemresultsinaspecificdistortionoftheplanetarymagneticfield.WedescribeallthetoroidalandpoloidalcurrentsconnectedtoeachotherthroughtheratioofthePedersenandHallionosphericconductivitiesaspartsofthetotalcurrentsystem.
11
![Page 12: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/12.jpg)
EnergyfluxofprecipitatingelectronsoverJupiter’smainauroralemissionAllegrini,F.,SouthwestResearchInstituteMauk,B.,Gladstone,G.R.,Bagenal,F.,Bolton,S.,Clark,G.,Connerney,J.E.P.,Ebert,R.W.,Greathouse,T.,Hue,V.,Hospodarsky,G.B.,Kurth,W.S.,Levin,S.,Louarn,P.,McComas,D.J.,Pollock,C.,Ranquist,D.,Thomsen,M.F.,Valek,P.W.,Wilson,R.J.
Jupiter’saurorae,themostpowerfulinthesolarsystem,arecausedbyenergeticelectronsprecipitatingfromthemagnetosphereintotheatmospherewheretheyexcitethemolecularhydrogen.TheJovianAuroralDistributionsExperiment(JADE)andJupiterEnergeticparticleDetectorInstrument(JEDI)onJunomeasuretheenergyandpitchangledistributionsoftheseelectronsandhelpusunderstandhowtheseaurorae,imagedbyJuno’sUltravioletSpectrograph(UVS),arecreatedandpowered.Mono-andbi-directionalfield-alignedelectronbeamsareobservedoverthepolarregionandmainemission,withbroadandpeakedenergyspectra.Whenflyingoverthemainemissionfromhighertolowerlatitudes,Junoobserveshigherenergyelectronsfirst(10sto100skeV)thatgraduallytransitiontolowerenergyelectrons(fewkeVtolessthan100eV).Theenergyfluxoftheprecipitatingelectronsisaproxyofhowmuchenergyisdepositedintotheatmosphereand,thus,canbecomparedwiththephotonintensityoftheaurora.Lookingattheenergyflux,thereseemstobeapatternwherethemainemissioncouldbepoweredbyhigherenergyelectrons(10sto100skeV)andthediffuseauroraequatorwardofthemainemissionbylowerenergyelectrons(lessthanafewkeV).Inthispresentation,weshowhowtheenergyfluxmapstotheauroralemissionsand,inparticular,howthecontributionsfromthedifferentenergyrangescontributetothedifferentemissions.
InternalversusexternalsourcesofplasmaatSaturn:OverviewfromMIMI/CHEMSdataAllen,R.C.,JohnsHopkinsAppliedPhysicsLabMitchell,D.G.,Paranicas,C.P.,Hamilton,D.C.,Clark,G.,Rymer,A.M.,Vines,S.K.,Roelof,E.C.,Krimigis,S.M.,Vandegriff,J.
Plasmacompositionobservationsprovideausefulmechanismforinvestigatingplasmasourcesandsubsequentevolutionwithinplanetarymagnetospheres.WhileHe++isthesecondmostabundantionspeciesinthesolarwind,therearenoknownsourcesofHe++ionswithinthemagnetosphereofSaturn,allowingHe++toserveasatracerofsolarwindionswithintheKronianmagnetosphere.Meanwhile,W+andH2
+,knowntooriginatewithinthemagnetosphereofSaturn,serveasatracerofinternallyionizedplasma.Inthispresentation,weinvestigatetherelativeabundancesandpropertiesofenergetic(32-220keV)ionspeciesoriginatingfromsourceswithinthemagnetosphereandfromthesolarwind.Solarwind-originatingionsareobservedtohavesignificantfractionalabundance(upto~0.05)inthemidnight,dawn,andnoonlocaltimequadrantsathighradialdistances(~40,~45,and~20RSrespectively).Severalpossibleentryprocesses,suchasreconnectionandKelvin-Helmholtzinstabilities,areoutlinedinthispresentationaswellasadiscussionofsubsequenttransport.
12
![Page 13: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/13.jpg)
EquatorialmagneticfieldoscillationsobservedovertheCassinimissionAndrews,D.J.,SwedishInstituteofSpacePhysicsCowley,S.W.H;Hadid,L.Z.;Hunt,G.;Morooka,M;Provan,G.;Wahlund,J.-E.
Wepresentacompleteanalysisoftheequatorialstructureoftheplanetaryperiodoscillationmagneticfield,asmeasuredbyCassinioverthecompletemission.Incontrasttopreviousrelatedwork,wenowfullyaccountfortheactionofthetwoindependentmodulationsassociatedwiththeauroralcurrentsystemsinthenorthern(N)andsouthern(S)hemispheres.Up-to-datephasemodelsareemployedtoorganisethedata,accountingforslowdriftsinoscillationperiods.WhilelimitedsomewhatbytheseasonalandspatialcoverageaffordedbyCassini’strajectoryaboutSaturn,weneverthelessobtain‘maps’oftheequatorialoscillationsforbothNandSsystemsindependently.Inaddition,usingpredeterminedvaluesfortheseasonallyshiftingamplituderatiobetweentheNandSsystems,weproduceasimilarmapoftheequatorialmagneticfieldusingallavailabledata,makingtheassumptionthatthespatialstructureoftheoscillatingfieldiscommontobothNandSsystems.Field-alignedcurrentdensitiesarethencomputedandcomparedtopreviouswork.LongitudinalvariationsofthesulfurionsintheIoplasmatorusobservedbytheHISAKI/EXCEEDArakawa,R.,TohokuUniversityTsuchiya,F.,Misawa,H.,Kagitani,M.,Suzuki,Reina,H.,F.,Yoshioka,K.,Kimura,T.,Murakami,G.,Yoshikawa,I.,Yamazaki,A.
WeanalyzedtimevariationsinintensitiesofEUVemissionsfromtheIoplasmatoruswithlongtermdatasetobtainedbytheHISAKI/EXCEEDtoderivetheSystemIVperiodicity,whichislongerthantheSystemIIIperiod(9.925h),duringtheHISAKIeraandfoundforthefirsttimethattheSystemIVperiodhasshortenedaftertheIovolcanicevent.ThedatausedinthisstudywasobtainedforNov.2014–May2015includingtheIovolcaniceventstartedinthemiddleofJan.,2015[Yonedaetal.,Icarus,2015].TofindtheSystemIVperiod,temporalvariationsintheSystemIIIlongitudeatthepeakofEUVintensitywerederivedbyasinusoidalfittothelightcurvesofsulfurions.TheSystemIVperiodsofS+(76.5nm)beforeandaftertheIo’svolcaniceventwere10.046±0.001hand9.989±0.001h,respectively.Ontheotherhands,theSystemIVperiodduringtheIo’svolcaniceventwas9.937±0.014h.ThetimingwhentheSystemIVperiodshortenedcorrespondstothetimingwhentransientauroraactivitiesenhanced.ThephaseofthelongitudinalmodulationofS3+(65.7nm)alsochangedabruptlyatthattimingintheorderfromtheoutertotheinnerpartofthetorus.ThesefactssuggestchangeinSystemIVperiodicitywasrelatedwiththeinjectionofhotplasma.WeexaminedtheeffectofthegradientBdriftoftheinjectedhotelectronandthecollisionrelaxationtimescaleoftheinjectedhotelectronwiththethermalelectronandproposethattheshortSystemIVperiodjustaftertheinjectionwasproducedbythegradientBdriftoftheinjectedhotelectronwhoseenergywasinafewkeVtoafewtenkeV.However,theoriginofthenormalSystemIVperiod,thatistheperiodicitybeforetheIovolcanicevent,isnotstillresolved.
13
![Page 14: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/14.jpg)
NeutraltoriinNeptune’smagnetosphereArridge,C.S.,LancasterUniversityRay,L.C.;Higgins,P.M.
NitrogenandhydrogenionsarethoughttobethemainionspeciesintheneptunianmagnetosphereandarethoughttoderivemainlyfromthelargesatelliteTriton.OthersourcesofneutralspotentiallyincludeNeptune’sexosphereandtherings.InthisworkweuseanewDirectSimulationMonteCarlo(DSMC)modelforneutraltoriinNeptune’smagnetospheretoinvestigateneutralsourcesatNeptuneandtheeffectsofplasma-neutralasymmetries.Themodelincludesincludeneutral-neutralandneutral-ioncollisions,photolysis,electronimpactionisation/dissociationandrecombination,andchargeexchangereactions(includingchemistry).Reactionsinvolvingionsandelectronsaremodelledusingasimplifiedplasmamodel,basedonVoyager2observations,whichincludesthelatitudinaldistributionforionsandelectrons.WealsoincludeawatergroupneutralsourcefromringarcsintheinnermagnetospheretoinvestigatethepresenceofadenseionsourceclosetoNeptune.AreSaturn’sInterchangeInjectionsOrganizedbyRotationLongitude?Azari,A.R.,UniversityofMichigan,ClimateandSpaceSciencesandEngineeringJia,X.,Liemohn,M.W.,Provan,G.,Ye,S.-Y.,Cowley,S.W.H.,Hospodarsky,G.B.,Paranicas,P.,Rymer,A.M.,Mitchell,D.G.,Sergis,N.,andThomsen,M.F.
Saturn’smagneticandplasmaenvironmenthasbeenextensivelystudiedoverthepastdecadeandahalfwiththerecentconclusionoftheCassinimission.PeriodicitiesintheplasmapropertiesandmagneticfieldhavebeenobservedatperiodscloselyrelatedtothoseoftheemissionpowerofSaturnKilometricRadiation(SKR),leadingtothehypothesisthattheprocesscontrollingSKRmodulationalsocontrolsaspectsofmagnetosphericphysics.Here,webuildonpreviousworkidentifyinginterchangeinjectionsfromhigh-energy(3-22keV)H+intensificationstoinvestigatewhetherinterchangeinjectionsdisplayperiodicitiessimilartoeitherSKRmodulationorotherphenomena.
InterchangeinjectionsareRayleigh-TaylorlikeplasmainstabilitiesandaprimarysourceofmasstransportinSaturn'smiddlemagnetosphere.Ourpreviousworkfoundthatenergeticprotoninjectionsarestronglyorganizedbylocaltimeandradialdistance.Here,weconsidertheorganizationbyseveraldifferentperiodicfluctuation-basedlongitudesystems.Iforganizedbyplanetaryoscillationphase,theninterchangewouldassistincommunicatingtheseperiodicitiesbetweentheinnerandoutermagnetosphereofSaturn.Wetakeadvantageoftherecentlyupdatedandnear-continuousdefinedSaturnlongitudesystem(SLS-5),whichisbasedonthemodulationphaseofSKR,alongwiththeplanetary–periodoscillationslongitudesystem(PPO),whichisbasedonmagnetosphericmagneticfieldmeasurements.Weanalyzethephasesystemdistributionforequatoriallyobservedinterchangein2005–2016andcomparethistopreviousstudies.
WecanreproduceapreviousfindinglinkinginjectionstotheSLSlongitudesystem,butonlyifthetimeinterval,spatialrange,andinjectionintensitylevelistightlyrestricted.Examinationsofthisrelationshipoverlongertimeintervalsandawiderrangeofinjectionamplitudes,however,revealnostrongconnectionwitheithertheSLS-5orPPOlongitudesystems.
14
![Page 15: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/15.jpg)
StatisticalplanetaryperiodoscillationsignaturesinSaturn’sUVaurorasBader,A.,LancasterUniversityBadman,S.V.andKinrade,J.andCowley,S.W.H.andProvan,G.andPryor,W.
Saturn'sauroralemissionsprovidegoodgroundsforinvestigatingfield-alignedcurrent(FAC)systemsintheplanet'smagnetosphericenvironment.Previousstudiesbasedonmagneticfielddatahaveidentifiedcurrentsystemsrotatingwiththeplanetaryperiodoscillations(PPOs)inbothhemispheres[e.g.,Hunt2014,2015],superimposedontothelocaltime-invariantcurrentsystemproducingthemainauroralemission.InthisstudyweanalyzethestatisticalbehaviourofSaturn'sUVauroralemissionsoverthefullCassinimissionusingallsuitablepubliclyavailableCassini-UVISimages.Wecalculateaccuratestatisticalboundariesandcenterlocationsoftheauroraloval.UsingPPOphaseanglesdeterminedby[Provan2016],weexamineauroralintensitiesandboundariesinareferenceframerotatingwiththePPOsystemineachhemisphere.StrongstatisticalintensificationsareobservedclosetotheexpectedlocationsofupwardFACsinmagneticlongitude,clearlysupportingthemainassumptionsofthecurrenttheoreticalmodel[e.g.,Provan2016].However,ananalysisofseparatetimeperiodswithdifferentrelativerotationratesandstrengthsofthenorthernandsouthernPPOsystemsindicatessomesortofinterhemisphericcouplingofthetwo,asthestatisticalvariationsinauroralintensityareobservedatshiftingmagneticlongitudes.Similarly,thepreviouslyobservedellipticmotionoftheauroraloval'scenters[e.g.,Nichols2015]isfoundtodependontherotationofbothPPOsystemsandtheirinteraction.
Saturn’sauroralprocesses:insightsfromtheCassiniGrandFinaleBadman,S.V.,LancasterUniversityBader,A.,Kinrade,J.,Pryor,W.,Esposito,L.,Radioti,A.,Grodent,D.,Yao,Z.,Palmaerts,B.,Lamy,L.,Brown,R.H.,Baines,K.,Buratti,B.,Clark,R.,Nicholson,P.,Sotin,C.,Melin,H.,Stallard,T.
Saturn’sauroralemissionsdisplayavarietyoffeaturesreflectingdifferentregionsofthemagnetosphere.The‘main’auroraisusuallydominatedbyadawnarcmappingtoouter,closedfieldlines.Itcanbecomplementedbyarcsandspots,sometimespulsating,athighlatitudes,likelyoccurringonfieldlinesopentothesolarwind.Diffusepatchesorarcsarealsodetectedatlowerlatitudescorrespondingtoparticlesprecipitatingfromtheinnerregions.Thedawnarcitselfhasahighlyvariableintensityandstructure,modulatedbyrotatingfeaturesandstorm-likeexpansions.WereviewSaturn’sauroralfeaturesandthedrivingmechanismsinlightofthemeasurementsmadeduringthehighlatitude,lowaltitudeGrandFinaleorbits.Wefocusontheintensityandpositionvariabilityobservedonsmallspatialscalesandhowtheunderlyingmechanismscancontributetotheglobalmagnetosphericdynamics.
15
![Page 16: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/16.jpg)
IsJupiteracolossalcomet?WillJunodecide?Bagenal,F.,UniversityofColoradoDelamere,P.A.
Jupiter’smagnetosphereisthelargeststructureinthesolarsystem,averagingabout150timesthewidthoftheplanet.ThesolarwindstreamspastJupiter,stretchingtheplanet’smagnetosphereintoalongtailthatcanreachpasttheorbitofSaturn.The0.5ton/siogenicplasmaisultimatelyejecteddownthetailandlosttothesolarwind.ThenatureofthesolarwindinteractionwiththemagnetospheremaybeverydifferentfromthatatEarth-morelikeacomet.Juno’sorbitoverJupiter’spolesisdesignedtoallowthespacecrafttomapJupiter’sgravityandmagneticfieldsandtheamountofwaterinitsatmosphere,butthepolarvantagepointalsoaffordsJunoaperfectopportunitytostudythiscompletelyunexploredregionofmagnetosphere.Someofthechargedparticlesinthemagnetospherearefunneledintothepolaratmospheretocreateintenseauroralemissions,whichJunoobserveswithunprecedentedresolution.Juno'sstretchedoutorbitaroundJupiterwillalsoenableittosampledifferentportionsofthemagnetosphereoverthecourseofthemission,buildingamorecompletepictureoftheaurorasandprocessesthatcontrolthem.Instrumentsonthespacecraftmeasurefluxesofparticlesthatinteractwiththeatmospheretogeneratetheauroras.Ultravioletandinfraredimagesprovidevisualcontextfordatafromthemagnetometer,plasmaandradio-waveinstruments,whichelucidatehowchargedparticlesareacceleratedto10sofkeVenergiesinJupiter'smagnetosphere.Inthisposterweillustratewaysthatmass,momentumandenergycouldbetransferredthroughthemagnetosphereandpresentideas,tobetestedbyJuno,aboutthemagnetictopologythatresemblesacometaryinteractionwiththesolarwind.ModelingtheFlowofMassThroughtheIo-EuropaSpaceEnvironmentBagenal,F.,UniversityofColoradoDols,V.,Cassidy,T.,Nerney,E.
Ground-basedobservationsinthe60sand70sindicatedIowaspeculiar.TheVoyager1flybyin1979discoveredvolcanismonIo,foundstrongUVemissionsfromanionizedtorus,andmeasuredthetorusplasmainsitu.OnitswaytoSaturntheCassiniUVISprovidedmonthsofhigh-qualityobservationsofthetorusemissions,tellingustheplasmacompositionandhowthetoruschangedafteravolcaniceruption.TheGalileospacecraftmeasuredmagneticandparticleperturbationsnearIoonseveralpasses.WhenThomas+2004wrotethepost-GalileoreviewofIo’sneutralcloudsandplasmatorusintheJupiterbookwethoughtthemainphenomenawereexplained–about1ton/sofsulfurandoxygenescapesIo,becomesionizedandtrappedinJupiter’smagneticfield,movesouttofillthevastmagnetosphere.Inthemeantime,newobservationsandmodelshaveemerged,andthereisimportantscienceintheunexplaineddetails.(i)Modelssuggest~90%oftheplasmamovesoutwardsfromIo(e.g.Delamere+2005)butweseethepeakdensityina“ribbon”extendinginsideIo’sorbit.
(ii)Ground-basedobservationsandVoyagerinsitudataindicatesthere’saphysicalgapbetweenthe“ribbon”andthecolddiscoftheinnertorus(Herbert+2008).
(iii)AddingtoknownneutralcloudsofatomicOandS,GalileoobservationsandmodelsshowmolecularSO2andSOarealsokey(Russell+2003;Dols+2008,2012).
(iv)JAXA’sHisakisatellitehasmonitored>3yearsofIotorusspatialandtemporalvariations.(v)ReanalysisofVoyagerSO2
+ionsquantifiesthedistributioninsideIo’sorbit.(vi)FocusonEuroparaisedideasofiogenicspeciesdeliveringusefulchemicalstothesurface.(vii)Europaisunlikelyamajorplasmasource,buttheescapingneutralsabsorbenergetic
particlesmovinginwardsfromtheoutermagnetosphere.
16
![Page 17: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/17.jpg)
SimulatingGanymede'sMagnetospherewithGraphicsProcessingUnitsBard,C.,NPPFellow,NASAGoddardSpaceFlightCenterDorelli,J.C.;Collinson,G.;Paterson,B.
Theresolutionrequiredtoresolvecurrentsheetswithinsimulationsofplanetarymagnetospheresresultingridsizesapproachingseveralhundredmillioncells.Runningtheseproblemsarefeasibleonlyforthelargestsupercomputers;however,graphicsprocessingunits(GPUs)provideanalternativemeansofquickeningcomputationalMHDsolvers.OneGPUcandotheworkofroughly80-100cores,allowingmodestGPUclusters(~8GPUs)tosimulateGanymedewithinreasonabletimescales.Wereportourprogressindevelopingathree-dimensionalHallMHDcodeoptimizedtorunonmultipleGPUsandbenchmarkitwiththeGanymedeG8flyby,reproducingpreviousresultsdemonstratingthataddingtheHalltermtotheidealOhm'slawchangestheglobalconvectionpatternwithinthemagnetosphere.WepresentnewresultsfortheGalileoG1flybyanddemonstratethataddingasimpleisotropicelectronpressuretermtoOhm'slawcausesadditionalchangestotheglobalmagnetosphericbehavior.Jupiter’shighenergyparticleenvironmentathighlatitudes:observationsfromJuno’sRadiationMonitoringInvestigationBecker,H.N.,JetPropulsionLaboratory,CaliforniaInstituteofTechnologyAlexander,J.W.,Brennan,M.J.,Guillaume,A.,Adumitroaie,V.,Perry,K.L.,Jorgensen,J.L.,Denver,T.,Gladstone,R.,Greathouse,T.K.,Hue,V.,Versteeg,M.H.,Adriani,A.,Mura,A.,Cicchetti,A.,Noschese,R.,Sordini,R.,Connerney,J.E.P.,Mauk,B.H.,Bolton,S.J.,Levin,S.M
TheJunospacecraft’snovelpolarorbittraverseshighmagneticlatitudes,andtheinneredgesofJupiter’srelativisticelectronbelt,passingwithin3400km(1.05Rj)ofthecloudtops.JunoisthefirstspacecrafttoorbitthisclosetoJupiterandthefirsttosampletheinnerradiationbeltsandpolarregionsextensively(plannedscienceorbitsachieveamappingwith<12degreelongitudespacingattheequator).Juno’sRadiationMonitoring(RM)InvestigationmeasuresMeVelectronfluxesatJupiterbyusingionizationsignaturesfrompenetratinghigh-energyparticles(usuallyconsidered“noise”byinstruments)astheinsituobservable.AcquisitionofimagesandhousekeepingdatafromseveralofJuno’sheavilyshieldedinstrumentsarecoordinatedforthepurposeofobservingpenetratingradiationencounteredduringeachscienceorbit.Thedataareanalyzedtoextractthecharacteristicsignaturesofpenetratinghigh-energyelectrons(>5MeVand>10MeV)andions(>100MeV)andderivecountrateswhicharethenusedtoinferexternalelectronfluxlevels.Sincearrivalin2016JunohasreturnedbountifuldatasetsandnewsurprisesaboutJupiter’sradiationenvironmentathighlatitudes.Encounterswiththehighlatitudelobesofthesynchrotronemissionregionrevealedrelativisticelectronintensitiesanorderofmagnitudelowerthananticipatedpriortoarrival.Apopulationofhighenergyheavyions(>100MeV/nucleon)wasanothersurprisingdiscoveryinthisregion.WepresenthighlightsoftheRMobservationstodate.
17
![Page 18: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/18.jpg)
Radio&PlasmaWaveInvestigation(RPWI)forJUpiterICymoonsExplorer(JUICE)–LangmuirprobeinvestigationsBergman,J.,SwedishInstituteofSpacePhysics(IRF)Wahlund,J.-E.,Eriksson,A.I.E.,Edberg,N.J.T.,Khotyaintsev,Y.,Morooka,M.W.,Santolik,O.,Retino,A.,andtheRPWIteam
TheRadio&PlasmaWaveInvestigation(RPWI)providesanelaboratesetofstate-of-the-artelectromagneticfieldsandcoldplasmainstruments,whereseveraldifferenttypesofsensorswillsamplethethermalplasma,DCelectricfields,electricandmagneticsignalsfromradio,plasmawaves,andmicrometeoriteimpacts.ThecapabilityoffourLangmuirprobes,ondedicatedbooms,tomeasuretheelectricfieldvectorfromDCto1.6MHz,andplasmaconvection(ExBdrift)allowsfordetailedinvestigationsofplasmaelectrodynamicsintheJoviansystemand,inparticular,howtheionospheresandsubsurfaceoceansoftheicyGalileanmoonscoupleelectrodynamicallytothehighlyvariableJovianmagnetosphere.Thecapabilityofatriaxialsearchcoilmagnetometer,togetherwiththeLangmuirprobes’capabilities,allowformeasurementsofthemagneticandelectricvectorfieldssimultaneouslybelow20kHz,toidentifyAlfvénandwhistlerwaves,filamentarycurrents,fluxropes,andelectrostaticstructuresinvolvedinthetransferofenergyandmomentumbetweendifferentparticlepopulationsintheinteractionbetweentheJovianmagnetosphereandtheionizedexospheresaroundtheicymoons.TheRPWIhasasignificantlyenhancedcapabilityofusingbothpassiveandactivemethodstoinferthecold(<100eV)plasmacharacteristicsandinferthebulkiondriftvelocityvector.Forinstance,thisallowsforin-situmeasurementsofthepartiallyionizedgasexhaustedbywaterrichplumesaboveactivesurfaceregionsontheicymoons.TheLangmuirprobeswillalsobeusedtomonitorelectricallychargeddustimpactsandidentifyanydust-plasmainteractions.Suchmeasurementsonopenvs.closedmagneticfieldlinesatGanymede,combinedwithmeasurementsoftheelectricfieldacceleratingtheseparticlestowardthesurface,willgiveinsightintosputteringprocessesandtheireffectsontheatmosphereandtheicysurfaceofthemoon.AnalysisofHST,VLTandGeminirecentobservationsofUranusatUV/IRwavelengthsBerland,C.,LESIA,ObservatoiredeParisL.Lamy,N.André,R.Prangé,T.Fouchet,T.Encrenaz,E.Gendron,X.Haubois
Late2014,HSTremotelyobservedtheUranus’magnetosphereduringstrongwindshocksinteractionswiththeSTISandCOSinstrumentsintheFar-UV.ACOShighresolutionspectrumwastakenjustafterSTISimagedlocalizedsouthernaurorae,afew10kRbrightintheH2bands,on2Nov.2014.TheanalysisofthissinglespectrumrevealstransientH2auroralemissions,providesafirstmeasurementofthediscalbedobeyond170nm(upto210nm)andbringsnewconstraintsonatmospherichydrocarbonsresponsibleforabsorptionofthesolarreflectedspectrumatlongwavelengths.AsimilarobservingcampaignofUranusinvolvingmulti-spectralobservationsatFar-UV,Near-IRandX-raywavelengthsduringactivesolarwindconditionswasexecutedlate2017,whentheplanetreachedanintermediateconfigurationbetweensolsticeandequinox.WewillpresenttheNIRimagesoftheplanettakenwithVLT/NACOusingadaptiveopticsandGemini/NIRIwhichdisplayextendedH3
+emissionregions.
18
![Page 19: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/19.jpg)
Titan'splasmainteractionBertucci,C.,InstitutodeAstronomíayFísicadelEspacio(UBA/CONICET)
Titanistheepitomeofamultivariateplasmainteractionbetweenadenseatmosphereandawindofplasma.LocatedintheconfinesofSaturn'srotatingmagnetosphere,Titan'susuallyinteractssubsonicallywiththeflappingmagnetodiskofitsparentplanet.Thisinteractionisunlikeanyotheratmosphericbodyofthesolarsystemasthedirectionsoftheincomingflowandthesolarphotonsvaryasafunctionofthemoon'sorbitalphase.Therearetimes,however,whenthesolarwindpressureisstrongenoughtoleaveTitanintheshockedandeveninthesupersonicsolarwind,whereacolissionlessbowshockwasdetected.Inthesecases,theenrichmentoftheexternalplasmawithTitan'scoldandsometimesheavyionsleadstocomplexmagneticfieldmorphologiesfromwhichthehistoryofitsmagneticenvironmentcanbereconstructed.Thiseffect,negligibleatMarsandVenus,isanotheressentialcharacteristicofTitan'splasmainteraction.InthistalkwewillreviewtheseandotherresultsfromtheCassinispacecraftaroundTitanandidentifysomeopenquestionsthatcouldbeaddressedinthenearfuture.AlfvénwingletsduetoplumesonEuropaandIoBlöcker,A.,UniversityofCologneSaur,J.,Roth,L.,Strobel,D.F.
OnIo,volcanicplumesarecommonandrecentobservationssuggestedthatEuropaalsopossessesplumeactivity.Weapplya3DmagnetohydrodynamicmodeltoanalyzetheeffectsofvolcanicplumesonIoandwatervaporplumesonEuropaonthemoons'plasmaenvironmentandtheirAlfvénwings.Plumesproducelocallyenhancedatmosphericdensities,andconsequentlyenhancedandlocalionosphericconductivities.Theseconductivitiescreatealocalionosphericelectriccurrentsystem.Includinglocalplumesinthemoons'atmospheres,weshowthatsuchlocaldensityenhancementsinfluencetheplasmainteractionlocallygeneratinganAlfvénwingletwithintheAlfvénwing.SinceEuropa'satmosphericcolumndensityisaboutafactorof100smallerthanIo’satmosphericcolumndensitywedemonstratethatdenseatmosphericinhomogeneitiesonEuropaaffecttheAlfvénicfar-fieldmuchstrongercomparedtoIo.Ourworkprovidesideasonhowtodetectplumesinfutureplasmaandfieldobservations.
19
![Page 20: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/20.jpg)
ThepolarregionofJupiter’saurora:barcodenoise,conjugateflaresandmore…Bonfond,B.,STARInstitute,UniversitédeLiège,BelgiumGrodent,D.,Gladstone,R.,Yao,Z.,Gérard,J.-C.,Greathouse,T.,Hue,V.,Versteeg,M.,Kammer,J.,Davis,M.,Radioti,A.,Paranicas,C.,Becker,H.,Bolton,S.,ConnerneyJ.,Levin,S.
Juno’sunprecedentedpolarorbitsaroundJupiterallowforuniqueobservationsofthepolarauroraeandrelatedphenomena.HerewemakeuseofJuno-UVS,theUVimagingspectrographoperatinginthe60-200nmrange,toexplorethepolarphysicsintwoverydifferentways.Inthefirstpartofthispresentation,wewillanalyzetherapidvariationsofthebackgroundnoisecausedby>10MeVelectronspenetratingtheinstrument.InUVimages,thisrapidlyvaryingsignaltakestheformofabarcode-likepattern.Wewilldiscussthemapping,thealtitudeandthecharacteristictimescaleofthe“barcodeevents”inordertoconstrainthemechanismsgivingrisetothem.Inthesecondpart,wewillcomparesimultaneousobservationsoftheauroraefromthetwohemispheres.OnedatasetcomesfromJuno-UVSwhiletheothercomesfromtheHubbleSpaceTelescopeSTISinstrument.Wewillshowthatmostauroralfeaturesinonehemispherehaveaclearcounterpartintheotherone.Amongotherexamples,wewillshowevidenceofconjugateflaresintheactiveregionofthetwohemispheres.However,otherstrongbrightnessenhancementsonlyshowupinonehemisphere,withoutanyechointheotherone.PlanetaryperiodmodulationsofreconnectioneventsinSaturn’smagnetotailBradley,T.J.,UniversityofLeicesterCowley,S.W.H.,Bunce,E.J.,Provan,G.,Palmaerts,B.,Smith,A.W.,Jackman,C.M.,Kurth,W.S.,Roussos,E.,Krupp,N.,Dougherty,M.K.
WenewlyanalyzemagneticfielddatafromthefinalorbitoftheCassinispacecraftinrelationtoalargeauroralstormobservedintheUVISdataset.Afielddipolarizationobservedat~9hUTonthe14September2017ataradialdistance~15RSinthenear-midnightnortherntailindicatesalargescalemagnetotailreconnectionevent,assupportedbyobservationoftheonsetofalowfrequencyintensificationofSaturnkilometricradiation(SKR)observedinRPWSdata,andasubsequentinjectionofhotplasmaobservedbyLEMMS.WithanelevatedradialcomponentofthemagneticfieldinSaturn’smagnetotailobservedpriortotheevent,weproposethestormisassociatedwithaninitialcompressionofthemagnetosphereviaasolarwindshock,andisthentriggeredundernear-optimumplanetaryperiodoscillation(PPO)conditionsassociatedwithathinnedtailcurrentsheetatalocalnorthernPPOphaseof~0°andalocalsouthernPPOphaseof~180°,inconformitywiththemodelofCowleyetal.[JGR-Space,2015JA023367,2017].Wesupportthisconclusionwithastatisticalanalysisof2094reconnection-relatedeventsinSaturn’smagnetotailidentifiedbySmithetal.[JGR-Space,2015JA022005,2016]usingCassinimagnetometertaildatafromintervalsduring2006and2009-10,whichwealsoorganizebyPPOphase.Theresultsshowclearmodulationoftheevents,withmostoccurringpreferentiallyattheabovelocalnorthernandsouthernphasesatwhichthetailcurrentsheetisthinnest.However,organizationoftheseeventsbythelocalPPOphaserotatingacrossthetailfromdusktodawnsuggestsamorelocalorigin,ratherthanthedominanceoflarge-scaleeventsthatsimultaneouslyaffectmuchofthetailwidth.WealsodiscusstherelationbetweentheseresultsandtheapparentlycontradictoryfindingsconcerningthemagneticPPOphasedependencyofmaximainSKRemissionsfromtheprincipalpost-dawnsources,whichoccurunderapproximateantiphasePPOconditions.
20
![Page 21: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/21.jpg)
VisualizingDatafromCassini,JUNO,andMoreUsingHAPI,Autoplot,andMIDLBrown,L.E.,JohnsHopkinsAppliedPhysicsLabVandegriff,J.D.,Faden,J.B.,Mitchell,D.G.,Kurth,W.S.
WepresentawaytovisualizeHeliophysicsdatafromCassiniandJUNO(andothermissions/datacenters)inacommontool.AnewaccessmechanismcalledtheHeliophysicsApplicationProgrammer'sInterface(HAPI)isbeingadoptedatmanydatacentersacrossHeliophysicsandplanetarysciencefortheservingoftimeseriesdata.TwoexistingtoolsarealsobeingenhancedtoreadfromHAPIservers,namelyAutoplotfromtheUniversityofIowaandMIDL(MissionIndependentDataLayer)fromTheJohnsHopkinsAppliedPhysicsLab.BothtoolswillbeabletoaccessdatafromRPWS,MAG,CAPS,MIMI,JEDI,andWaves.Inadditiontobeingabletoaccessdatafromeachother'sinstitutions,thesetoolswillbeabletoreadfromallthenewdatasetsexpectedtocomeonlineusingtheHAPIstandardinthenearfuture.ThePDSplanstouseHAPIforalltheholdingsatthePlanetaryandPlasmaInteractions(PPI)node,asdoesCDAWebatGoddardSpaceFlightCenter.WewilldescribethenewHAPIdataservermechanismanddemonstratethevisualizationandanalysistools.ObservationsofSaturn’sRingCurrentduringtheCassiniGrandFinaleOrbitsBunce,E.J.,UniversityofLeicesterProvan,G.,Cowley,S.W.H.,Achilleos,N.,Cao,H.,Dougherty,M.K.,andHunt,G.J.
Saturn’sringcurrentflowsintheequatorialmagnetosphereeastwardaroundtheplanetextendingthefieldlinesradiallyoutward.Earlynear-equatorialCassiniorbitswereusedtodeterminethestrengthandradialextentofthecurrent,showingthatthisvariesstronglywiththesizeofthemagnetospheredependentonthedynamicpressureofthesolarwind[Bunceetal.,2007].Theinneredgeofthecurrentliesatanequatorialradialdistanceof~7RS,whiletheradiusoftheouteredgevariesbetween~15RSwhenthemagnetosphereiscompressedto~22RSwhenitisexpanded.WhendatafromthefirsthighlyinclinedCassiniorbitsbecameavailable,thefirstmeasurementsofthenorth-souththicknessofthecurrentsheetweremade,withvaluesbeingtypically~3RSonthedayside,and~1to~5RSonthenightside[Kellettetal.,2009].Hereweinvestigatethefirstsystematicobservationsofringcurrentperturbationsintheresidualmagnetosphericfield(followingsubtractionoftheinternalmagneticfieldmodel)insidethemaincurrentcarryingregionduringtheGrandFinaleorbits.ThesecylindricalfieldcomponentsarecomparedwiththeSaturnmagnetodiscmodel[Connerneyetal.,1981;Edwardsetal.2001].Duringthistimethespacecraftcrossednorthtosouthinsidetheinneredgeofthecurrentcarryingregion,between~1.05RSand~2.5RS.WefindthattheBρ fieldassociatedwiththeringcurrentinthisregionisnear-zero,andthemainringcurrentobservableisthenorth-southcomponentofthefield,Bz.Followingpreviouswork,wecaninferthevalueoftheringcurrent‘amplitude’µI0(nT)fromthestrengthoftheaxialBzfieldatthecentreofthering(equivalentlySaturn’s‘Dst’),assumingaconstantvaluefortheringcurrentthickness.WecomparethevariabilityofthisparameterduringtheGrandFinaleorbitswiththatfrompreviousequatorialobservations,anddiscusstheimplicationsforthedynamicsoftheringcurrentingeneralterms.
21
![Page 22: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/22.jpg)
QuantifyingKelvin-HelmholtzdrivenvariabilityofplasmaconditionsnearSaturn'smagnetopauseboundaryBurkholder,B.L.,GeophysicalInstitute-UniversityofAlaskaFairbanksDelamere,P.A.
TheauroralformsthatJunoisobservingmakeitclearthatthesolarwindinteractionforagiantmagnetosphereisfundamentallydifferentfromEarth's.Thelargedifferenceinthescaleofthesystem,aswellasacontinuouslyreplenishedinternalsourceofplasmawhichsubcorotatesouttothemagnetopauseboundary,couplesthesolarwindtothemagnetospheresofJupiterandSaturninawaythatisperhapsstrongerthantheterrestrialcase.IncontrasttoattemptstoquantifyaDungeycycleforthegiantmagnetospheres,aviscous-likeinteractionproposedbyAxfordandHines[1961]canbeinvokedintheformoftheKelvin-Helmoltzinstabilityactingonthemagnetopauseboundary.Cassiniplasmadatahaveshownthattheasymmetricflowshearatthemagnetopausewithrespecttolocaltimeresultsinanasymmetryinthemagnetosheathflowvelocity.WebuildontheseresultsbyexaminingthedatafortheportionofthemagnetosphericplasmathatCassinitraverseswithin100minutes(0.25-0.5Saturnradii)ofthemagnetopause.Further,usingthemagnetometerdata,wehaveidentifiedabimodaldistributionofactiveandquietmagneticfieldfluctuationsinthemagnetosphere.SomeactiveeventsnearthemagnetopausemaybeassociatedwiththeturbulentheatingfoundinactivelygrowingKHvortices.ThedataanalysisiscomparedwithresultsfromahybridsimulationofaKHunstableportionofthemagnetopauseboundary.WeusestresstensoranalysistoquantifythetransportofmomentumacrossthemagnetopauseasaresultofMaxwellandReynoldsstresses,andwecalculateheatingratesfromthesimulatedmagneticfieldfluctuations.Wealsoconductsimulationsinwhichthemagnetosphericsideoftheboundarycontainsheavyionsand/orasuperthermalvelocitydistributionasisthecaseatSaturn.CassiniMagnetosphericScienceDisciplineEnd-of-MissionPDSDataProductsBurton,M.E.,JetPropulsionLaboratory
TheCassinispacecraftmadeitsfinalplungeintotheinteriorofSaturninmid-September,2017.Sincethattime,theCassiniprojecthascontinuedandthemainfocushasbeentocapturetherichlegacyofthatlong-livedmission.Eachofthe12scientificinstrumentsandthevariousscientificdisciplines,includingtheMagnetosphericSciencedisciplinehaveidentifiedandarchiveddataproductsatthePlanetaryDataSystem(PDS)thatarelikelytobeusefultofuturescientists.Thoseproductsinclude:higherorderdataproducts,updatedinstrumentdataUserGuides,detailedspacecrafttrajectoryinformation,eventidentificationlists(eg.,magnetopause,bowshockcrossings)andspacecraftobservationlists(eg.,Cassiniremotesensingauroralobservations).ThisposterprovidesanoverviewofthedataproductsthatwillbemadeavailableatthePDStofuturescientistinterestedinstudyingSaturn’smagnetosphere.
22
![Page 23: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/23.jpg)
Saturn’sInternalMagneticFieldRevealedbyCassiniGrandFinaleCao,H,HarvardUniversityDougherty,M.K.,Khurana,K.K.,Hunt,G.J.,Provan,G.,Kellock,S.,Burton,M.E.,Burk,T.A.,Bunce,E.J.,Cowley,S.W.H.,Kivelson,M.G.,Russell,C.T.,Southwood,D.J.
Saturn’sinternalmagneticfieldcontinuestooffersurprisessincethefirstin-situmeasurementsduringthePioneer11Saturnflyby.TheCassinispacecraftenteredtheGrandFinalephaseinApril2017,duringwhichtimethespacecraftdivedthroughthegapbetweenSaturn’satmosphereandtheinneredgeoftheD-ring22timesbeforedescendingintothedeepatmosphereofSaturnonSep.15th2017.TheunprecedentedproximitytoSaturn(reaching~2550+/-1290kmabovetheclouddeck)andthehighlyinclinednatureoftheGrandFinaleorbitsprovidedanidealopportunitytodecodeSaturn’sinternalmagneticfield.ThefluxgatemagnetometeronboardCassinimadeprecisein-situvectormagneticfieldmeasurementsduringtheGrandFinalephase.MagneticsignalsfromtheinterioroftheplanetandvariousmagnetosphericcurrentswereobservedduringtheGrandFinalephase.HerewewillreportnewfeaturesofSaturn’sinternalmagneticfieldrevealedbymeasurementsfromtheCassiniGrandFinalephase.WewillshowthedirectlydeterminednorthwardoffsetofSaturn’smagneticequatoranditvariations.Small-scaleyethighlyconsistentmagneticstructuresweredetectedalongeveryGrandFinaleorbits.Whenexpressedinspectralspace,intrinsicmagneticmomentsuptoatleastdegree9areneededtodescribethesemagneticstructures.ImplicationsforthedeepinteriorofSaturnwillbediscussed.DiurnalandSeasonalVariabilityofIceGiantMagnetospheresunderDifferentIMFConditionsCao,Xin,GeorgiaInstituteofTechnologyCarolPaty
Inordertostudythedynamicandasymmetricstructureoficegiantmagnetopauses,weproposeaquantitativeapproachtomeasuretheasymmetriesofthemagnetosphericboundaries.First,weuseanumericalmodel(multifluidMHD)tosimulatetheglobalmagnetosphereofUranus,whichhasanextremelydynamicandasymmetricmagnetosphereduetoitshighobliquityanditsseverelytiltedandoffcentereddipolemoment.WeinvestigatethemagnetosphericinteractionwiththesolarwindforarangeofInterplanetaryMagneticField(IMF)orientationsandstrengthsforbothequinoxandsolsticeseasons.Basedontheresultsofoursimulations,weuseapreviouslydevelopedanalyticalmodelfortheshapeofthemagnetopausetofitthemagnetopauseboundaryofUranusandanalyzethecharacteristicsofthemagnetopausesuchasthevariationoftheflaringparameterandthecuspindentation.Inthisway,wecandeterminetheinfluenceofseasonalityandsolarwindconditions(externaldrivers)aswellastheintrinsicfieldgeometry(internal)onthemagnetosphericasymmetry.TheresultsofthisinvestigationillustratethecomplexinteractionofUranus'magnetosphere;thatitisstronglyinfluencedbothbyseasonalityandIMForientation,butthatunderlyingandpredictablesignaturesexistduetotherotationofsuchanasymmetricintrinsicfield.WeapplythesesamemethodstotheinvestigationofNeptune'smagnetosphere,andpresentpreliminaryresultsinthecontextofcomparativeplanetologywithUranus.Thisstudymayproveusefulforpredictingthemagnetopauseboundarydetectioninfuturespacemissionstoicegiantsaswellasforindicatingwhatconditionsmaygenerateenhancedcuspsandthepotentialforcuspaurora.
23
![Page 24: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/24.jpg)
UsingtheGalileoSolid-StateImagingInstrumentasaSensorofJovianEnergeticElectronsCarlton,A.K.,MassachusettsInstituteofTechnology,DepartmentofAeronauticsandAstronauticsdeSoria-SantacruzPich,M.,Kim,W.,Jun,I.,andCahoy,K.
Dedicatedinstrumentstomonitorthehigh-energyradiationenvironmentarenotalwaysincludedonspacecraftduetoresourcelimitations;however,high-energyelectronsinJupiter’smagnetosphereaffecttheoperation,performance,andlifetimeofspacecraftandtheirinstruments.Wedevelopatechniquetoquantitativelycharacterizethehigh-energyelectronenvironmentusingtheGalileospacecraftSolid-StateImaging(SSI)instrumentandparticletransportsimulationsinGeant4.Wepost-processrawSSIimagestoobtainframeswithonlytheradiationcontribution.Thecamerasettings(gainstate,filter,etc.)areusedtocomputetheenergydepositedineachpixel,whichcorrespondstotheintensityoftheobservedradiationhits.TheenergydepositedintheSSIpixelsbyincidentparticlesfromprocessedSSIimagesiscomparedwiththeresultsfrom3DMonteCarlotransportsimulationsoftheSSIusingGeant4.SimulatingtheresponseoftheSSIinstrumenttomono-energeticelectronenvironments,wefindthattheSSIiscapableofdetecting>10MeVelectrons(90%confidence).UsinggeometricscalingfactorsfortheSSI,wecomputetheenvironmentparticlefluxgivenanumberofpixelswithradiationhits.WecomparetheSSIresultstomeasurementsfromtheGalileoEnergeticParticleDetector(EPD),examiningtheelectronfluxesfromthe>11MeVintegralfluxchannel.WefindagreementwiththeEPDdatawithinthe3-sigmadeviationoftheEPDdatafor40outof43(92.03%)oftheSSIimagesevaluated.Thisapproachcanbeappliedtoothersetsofimagingdatainenergeticelectronenvironments,suchasfromstartrackersingeostationaryEarthorbit.ConstrainingGanymede’sneutralandplasmaenvironmentthroughnumericalsimulationsofitsionosphereCarnielli,G.,ImperialCollegeLondon,UKGaland,M.;Modolo,R.;Leblanc,F.;Leclercq,L.;Beth,A.;Huybrighs,H.L.F.;Jia,X.
Ganymede’sionospherehasbeenpartiallycharacterizedbyfewin-situobservationsbytheGalileospacecraft.Manyofitsproperties,suchascomposition,dynamics,andinteractionwiththemoon’sownmagneticfield,remainpoorlyunderstood.GanymedeisalsothekeymoontargetedbytheJUICEmission.Inthiscontext,wehavedevelopedacomprehensive,ionosphericmodelforGanymedewhichaimstobeausefultoolinpreparationtothemission.Itwouldbeessentialtointerpretdata,suchasenergydistributionandmomentsfortheenergeticionsandneutralsfromPEP,ionosphericdensitiesfromRPWI,andtodisentangledifferentcontributionstothemagneticfield.
Ourmodelisbasedon3Dmulti-speciestestparticleMonteCarlosimulationswithtwokey,fixedinputs:theexosphereandelectromagneticfieldconfigurationsaroundthemoon.Theionosphereisgeneratedfromionizationoftheneutralexosphereviatwomechanisms:photoionizationinthedaysideandelectron-impactionizationintheregionsofopenmagneticfieldlines.Theoutputsofthesimulationincludeindividualtestparticletrajectoriesand3Dmapsofnumberdensity,bulkvelocityandtemperaturefordifferentionspecies.
Wefindthattheionosphereishighlynon-uniform,reflectingthecomplexstructureofGanymede’smagnetosphere.ThedominantionspeciesisfoundtobeO2
+.UnlikeJovianmagnetosphericions,ionosphericionsarefoundtoconcentrateandimpactthesurfaceintheequatorialregionovertheorbitalleadinghemisphere.BycomparingtheresultsofoursimulationwithobservationsfromGalileoduringtheG2flyby,wefindthattheionosphericnumberdensityisunderestimatedbyatleastoneorderofmagnitude,whiletheenergydistributionsmatchremarkablywell.Weattributethediscrepancyintheionosphericdensitytotheneutralexosphere,which,weargue,isunderestimated,especiallyneartheboundarybetweenopenandclosemagneticfieldlines.
24
![Page 25: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/25.jpg)
ComparativeModelingoftheMagnetosphereofSaturnandJupiterCassidy,T.M.,LaboratoryforAtmosphericandSpacePhysics,Univ.ofCO,Boulder
GiventhesimilaritiesbetweenIoandEnceladus,botharelargegassourcesintherapidlyspinninginnermagnetospheresofgiantplanets,thedifferencesinmagnetosphericchemistrybetweenJupiterandSaturnaresurprising.Saturnissurroundedbyaneutralcloudwithasmallfractionofionizedspeciesanditsenergyoutputisdominatedenergeticneutralatomescape.PlasmadominatesatJupiteranditlosesenergyprimarilybyUVradiation.
WeusedthechemistrymodeldevelopedbyFleshmanetal.toexplorethereasonsforthesedifferences.Thisrequiredtheadditionsofphysicalprocessesignoredintheearlierwork.Themostimportantforthisstudyincludeenergylossbyelectronexcitationofwatermoleculesandchargeexchangebetweenmolecularionsandatomicneutrals.Wealsocorrectedanerrorinthecalculatedcrosssectionofhydroniumionproduction.Fleshmanetal.usedacrosssectionappropriateforlow-energy(300K)reactions,andsooverestimatedthehydroniumproductionratebytwoordersofmagnitude.Withthatcorrection,themodeledhydroniumdensityisnegligiblecomparedtootherwatergroupions.
WiththesecorrectionsimplementedwealteredtheinputparameterstoseewhatwouldberequiredtopushSaturn’smagnetosphereintoajovian-likestate.Themostimportantdifferenceistheexternalenergyinputfromelectronsinthe10sto1000sofeV.ExternalenergyinputmakeslittledifferenceatSaturn.Butthisalonedoesnotresultintheobservediontoneutralratio>>1.Thatrequiresanatomicsource(OandHforthismodel)ratherthanH2O,whichisextremelyefficientatquenchingelectronenergy.ThehigherpickupionenergyatIoalsocontributes,butislessimportantforwaterchemistrythanthemuchheavierSandOchemistryatJupiter.
PhysicsandObservationsofauroralradioemissionsatJupiterandSaturnCecconi,B.,LESIA,ObservatoiredeParis
Auroralradioemissionsareintenseelectromagneticwavesproducedbynonthermalplasmainstabilitiesinplanetaryauroralregions.ThepresentationpresentsthecurrentknowledgeonthephysicsofauroralradioemissionsatJupiterandSaturn,introducingtheradiosourceemissionprocesses,namelytheCyclotronMaserInstability,aswellasitsassociatedphenomenology.Theinstrumentsusedtoobservethem(fromspaceandfromground)arealsodescribed,andrecentresultsfromtheCassiniandtheJunomissionarepresented.
25
![Page 26: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/26.jpg)
GlobalMHDsimulationsofSaturn'smagnetosphereChané,E.,UniversityofLeuven
Inthiswork,wehaveadaptedourglobalmodelofJupiter'smagnetospheretoSaturn.UsingthecodeMPI-AMRVAC,wemodelinthreedimensionstheinteractionsbetweentheKronianmagnetosphereandthesolarwind.TheMHDequationsaresolvedonasphericalnon-uniformmeshrangingfrom3Rs(innerboundary)to200Rs(outerboundary).Thecouplingwiththeionosphereisintroducedbyaddingion-neutralcollisionstotheMHDequationsinanregionjustabovetheinnerboundary.Thesecollisionsacceleratetheplasmaintheionosphericregion(whichinitiatestherotationofthemagnetosphere)andmakeelectricalcurrentclosurepossibleintheionosphericregion(becausetheion-neutralcollisionsgeneratefinitePedersenandHallconductivities).WeassumethattheneutralparticlesintheionospherearerigidlycorotatingwithSaturn.Themass-loadingassociatedwithEnceladusisincludedasanaxisymmetrictoruscenteredat5.5Rs.Wecomparetheoutputofthesimulationswithinsitumeasurements,remotesensingobservationsandanalyticalmodels.Inaddition,weinvestigatehowvariationsinthesolarwindaffectthemagnetosphere.MegavoltpotentialsoverJupiter’spolarcapregionClark,G.,JHU/APLMauk,B.H.,Paranicas,C.,Kollmann,P.,Haggerty,D.,Rymer,A.,Mitchell,D.G.,Saur,J.,Bolton,S.,Connerney,J.E.P.,Levin,S.
OneofmanysurprisesfromJuno’sexplorationofJupiter’spolarmagnetosphereisthediscoveryofprecipitatingionswithMaxwellian-likeenergydistributionsashighasseveralmega-electronvolts(MeV).ThecasestudyanalysisofPerijove(PJ)3observationsrevealedthattheseionsaremagnetosphericinoriginandtheirreminiscentinverted-Vspatial/temporalprofilecanlastaslongas10minutesorseveraldegreesinlatitude–indicatingverylargescalepotentialstructures.Inaddition,thestudybyClarketal.[2017]hypothesizedthatthesestructureswereassociatedwithadownwardcurrentregioninJupiter’smiddle-to-outermagnetosphereandthelargepotentialswereaconsequenceofsparsecurrentcarriersinthehigh-latitudepolarregion(basedofftheideasfromterrestrialstudies[e.g.,TemerinandCarlson,1998]).InthispresentationwepresentnewandmorerecentJunoobservationsoftheselarge-scale,peakedMeViondistributioninJupiter’spolarcap.Severalopenquestionsremainabouttheirexistence,suchas:1)howaremegavoltpotentialsformedinJupiter’spolarcap;2)dotheymapoutlargescalepotentialstructuresofadownwardcurrentregion?;3)aretheseionsconnectedtothegenerationofX-rayemissions?;4)aretheseionscausallyconnectedtotheupwardMeVelectronsobservedbyMauketal.,2017andParanicasetal.,[2018]?Definiteanswerstothesequestionsarenotexpectedinthispresentation,butanalysisoftheseeventsandmodelingofthecurrent-voltagerelationshipsinJupiter’sdownwardcurrentregionareexpectedtoprovideclues.
26
![Page 27: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/27.jpg)
ThoughtsontheProductionofJupiter’sAuroraClarke,J.T.,BostonUniversity
RecentmeasurementsofauroralemissionsandrelatedmagnetosphericprocessesatJupiterfromtheJUNOmissionhaveprovidednewinsightsintohowtheauroraareproduced.HighresolutionimagesofbothIRandUVauroralemissionsprovidekeyinformationabouttheproductionoftheaurora,complementedbymapsoftheUVauroralcolorratio.Theexistenceofnear-simultaneousdataonfield-alignedpopulationswiththebrightnessdistributionoftheauroralemissionsatthebaseofthesamefluxtubesiskey,andhascomewithsurprisescomparedwiththeoreticalexpectations.ThistalkwillemphasizethatwhileweoftenthinkaboutJupiterinthecontextofourunderstandingoftheEarth’saurora,theconditionsaresodifferentatJupiterthatthisisadangerousapproach.Wearenowapproaching40yearsofobservationsofJupiter’saurora,andmaybejuststartingtounderstandhowdifferenttheyarefromthoseattheEarth.InthistalkspecificexampleswillbepresentedalongwithsuggestionsfornewwaysofthinkingaboutJupiter.
TheeffectofsubcorotationonJupiter'sSystemIVperiodicityCoffin,D.A.,UniversityofAlaskaFairbanksDelamere,P.A.
JupiterexhibitsafundamentalrotationalperiodicityknownasSystemIVthathasnowidely-acceptedexplanation.ThisSystemIVperiodicityisparticularlyobservedinultravioletemissionfromtheIoplasmatorus.ToattackthisproblemwemodeltheresponseoftheIoplasmatorustosuperthermalelectronmodulationandvolcaniceruptionsusingatwo-dimensionalphysicalchemistrymodel(Copperetal.,2016).Themodelincludesradialandazimuthaltransport,latitudinally-averagedphysicalchemistry,andprescribedSystemIIIsuperthermalelectronmodulationfollowingSteffletal.,[2008].VolcaniceruptionsaremodelledasatemporalGaussianenhancement(e.g.,2x)oftheneutralsourcerateandhotelectronfraction(e.g.,<1%).However,weadoptanalternativeapproachfortheSteffletal.,[2008]SystemIVelectronmodulation.Couplinghotelectronstoradialtransport,themodulationisdeterminedbytheradialfluxtubecontentgradient.Radially-dependentsubcorotationisprescribed,consistentwithobservations[Brown,1994;Thomasetal.,2001].WeshowthattheSystemIV-likeperiodicityisdeterminedbyaninterplaybetweenphysicalchemistry,radialtransport,andaradiallydependentsubcorotationprofile.OurmodelusesaGaussiansubcorotationprofiledependentonamplitudeofsubcorotation,L-shelllocationofthepeakamplitude,andthewidthoftheGaussianprofile.WedemonstratethatvariationofthisprofileissufficienttoexplainobservedshiftsbyafactoroftwooftheSystemIVperiod[Ryoetal.,2017].
27
![Page 28: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/28.jpg)
AK-meansClusteringApproachtotheNumberofStatesoftheJovianandTerrestrialMagnetopausesCollier,M.R.,NASA/GSFCGruesbeck,J.R.;Connerney,J.E.P.;Joy,S.P.;Hospodarsky,G.B.;Roberts,A.;Sibeck,D.G.;andRoelof,E.C.
Previousstudies[e.g.,Joyetal.(2002),ProbabalisticmodelsoftheJovianmagnetopauseandbowshocklocations,J.Geophys.Res.,107,A10,doi:10.1029/2001JA009146;Walkeretal.(2005),ThelocationsandshapesofJupiter’sbowshockandmagnetopause,AIPConf.Proc.781,95,doi:10.1063/1.2032681]havesuggestedthattheJovianmagnetopausepositionhasabimodaldistributionimplyingthattheJovianmagnetopauseisatwo-statesystem.Weappliedak-meansclusteringanalysismodifiedtoaccommodatecurve-fittingtoboththeJovianandterrestrialmagnetopausecrossings.Thetraditionalk-meansapproachisadaptedtocurvefittingbysubstitutingaleast-squarescurvefittingtoaclusterofpointsinplaceofcalculatingthemeanofthepointsandsubstitutingthedistancefromeachpointtothefittedcurveinplaceofthedistancefromeachpointintheclustertothemeanpositionoftheclusterpoints.OurresultsindicatethattheJovianmagnetopauseisbest-describedasatwo-statesystemwhereastheterrestrialmagnetopausehasonlyonestateindicatingthatthebehavioroftheJovianmagnetopauseisfundamentallydifferentthanthatoftheterrestrialmagnetopause.Theoriginofthiscontrastingbehaviormaybethedisparatesourcestrengthssupplyingthetwomagnetospheres.WhereastheJoviansatelliteIosuppliesaboutametrictonofheavyionspersecondtotheJovianmagnetosphere,theterrestrialsource,Earth’sionosphere,isovertwoordersofmagnitudeweaker[e.g.,Bagenal,F.(1992),Giantplanetmagnetospheres,Annu.Rev.EarthPlanet.Sci.,20,289-328].
NewresultsfromGalileo'sfirstflybyofGanymede:Reconnectiondrivenflowsatthelow-latitudemagnetopauseboundary,crossingthecusp,andicyionosphericescapeCollinson,G.A.,NASAGoddardSpaceFlightCenterPaterson,B.,Bard,C.,Dorelli,J.,Glocer,A.,Sarantos,M.,WIlson,R.J.
Onthe27thofJune1996,theNASAGalileospacecraftmadehumanity'sfirstflybyofJupiter'slargestmoon,Ganymede,discoveringthatitistheonlymoonknowntopossessaninternallygeneratedmagneticfield.ResurrectingtheoriginalGalileoPlasmaSubsystem(PLS)dataanalysissoftware,weprocessedtherawPLSdatafromG01,andforthefirsttimepresentthepropertiesofplasmasencountered.EntryintothemagnetosphereofGanymedeoccurredneartheconfluenceofthemagnetopauseandplasmasheet.Reconnection-drivenplasmaflowswereobserved(consistentwithanEarth-likeDungeycycle),whichmaybearesultofreconnectionintheplasmasheet,magnetopause,ormightbeGanymede'sequivalentofaLow-LatitudeBoundaryLayer.DropoutsinplasmadensitycombinedwithvelocityperturbationsafterwardssuggestthatGalileobrieflycrossedthecuspsintoclosedmagneticfieldlines.Galileothencrossedthecusps,wherefield-alignedprecipitatingionswereobservedflowingdownintothesurface,atalocationconsistentwithobservationsbytheHubbleSpaceTelescope.ThedensityofplasmaoutflowingfromGanymedejumpedanorderofmagnitudearoundclosestapproachoverthenorthpolarcap.Theabruptincreasemaybearesultofcrossingthecusp,ormayrepresentanaltitude-dependentboundarysuchasanionopause.Morediffuse,warmerfield-alignedoutflowswereobservedinthelobes.Fluxesofparticlesnearthemoononthenightsideweresignificantlylowerthanonthedayside,possiblyresultingfromadiurnalcycleoftheionosphereand/orneutralatmosphere.
28
![Page 29: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/29.jpg)
ADegree10SphericalHarmonicModelofJupiter’sMagneticFieldfromtheJunoMagnetometerInvestigationConnerney,J.E.P.,SpaceResearchCorporationOliversen,R.J.,Espley,J.R.,Kotsiaros,S.,Joergensen,J.L.,Joergensen,P.S.,Merayo,J.M.G.,Herceg,M.,Bloxham,J.,Moore,K.M.,Bolton,S.J.,Levin,S.M.
CharacterizingtheplanetarymagneticfieldofJupiterisoneoftheprimaryscienceobjectivesoftheJunoMission.Juno’s53.5-daycaptureorbittrajectorycarriesherscienceinstrumentsfrompoletopoleinapproximately2hours,withaclosestapproachtowithin1.06Rjofthecenteroftheplanet(oneRj=71,492km),justafewthousandkmabovetheclouds.Observationsacquiredduring8ofJuno’sfirst9orbitsprovidethefirsttrulyglobalcoverageofJupiter’smagneticfieldwithacoarselongitudinalseparationof~45degreesbetweenperijoves.Observationsacquiredwithin~7RjofJupiterduringthefirst9polarpassesareusedtocharacterizetheplanetarymagneticfieldwithextraordinaryspatialresolution.Themagneticfieldisrepresentedwithadegree20sphericalharmonicmodelfortheplanetaryfield,combinedwithanexplicitmodelofthemagnetodisc.Partialsolutionoftheunderdeterminedinverseproblemusinggeneralizedinversetechniquesyieldsamodel(“JRM09”)oftheplanetarymagneticfieldwithsphericalharmoniccoefficientsdeterminedthroughdegreeandorder10,providingthefirstdetailedviewofaplanetarydynamobeyondEarth’s.TheJovianmagneticfieldisunlikeanythingpreviouslyimagined,evidencingacomplexitythatportendsgreatinsightintothedynamoprocessingeneralandthedynamicsofJupiter’sinteriorinparticular.Wepresentadegree10sphericalharmonicmodeloftheJovianmagneticfieldandillustrateitscharacteristicsviaasetofmapsofthesurfacefield,andconsiderimplicationsforparticlemotion,auroralemissions,andthedynamo.
EnergeticneutralsfromtheEuropainteraction:FinitegyroradiuseffectsCrary,F.J.,UniversityofColorado,Boulder,LASP
TheinteractionbetweenEuropageneratesenergeticneutrals,asthebackgroundionschargeexchangewithmolecularoxygeninEuropa'satmosphere.Thissourceofenergeticneutrals,andnon-so-energeticneutrals,mayimpactthesurfaceandproduceenhancedsputtering,mayremaingravitationallyboundtoEuropaandproduceanextendedcorona,mayescapetojovianorbitandproduceanneutralcloudorbesufficientlyenergetictoescapethesystementirely.Inthelatercase,theenergeticneutralfluxwouldbeobservablebyspacecraftatasignificantdistancefromEuropa.
Dolsetal.,2016,foundthatmostoftheseenergeticneutralswouldnotbeadirectproductofchargeexchangebetweenbackgroundionsandtheatmosphere.Instead,theinitialchargeexchangewouldproduceanO2
+ioninaringdistributionandthisionwouldsubsequentlychargeexchangewithanotheratmosphericneutral,producinganenergeticneutralandanewioninaringdistribution,whichthenmightexperienceyetanotherchargeexchange,etc.
Thisringdistributionsourceproducesaenergeticneutralwithcharacteristicenergyandangulardistribution,andthisdistributionismodifiedbythefactthatboththeatmosphericdensityandconvectionelectricfieldvaryonscalescomparabletothepickupgyroradius.Inthispresentation,Ishowaanalyticformforthisenergeticneutralsourcefunction,accountingforthesefinitegyroradiuseffects.
29
![Page 30: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/30.jpg)
MagneticinductionsignaturesfromanoceanwithinTritonCrary,F.J.,UniversityofColorado,Boulder,LASPBrain,D.A.andCaldwell,C.A.
Thesubsurface(ormediterranean)oceanwithinEuropawasdetectedthroughitsinducedmagneticdipole.ThisisgeneratedbythechangingbackgroundmagneticfieldfromJupiter,whichrotateswitha11.2hour(synodic)period.Thissignatureshowsthatthereisanelectricallyconductivelayerwithinthebody,butitdoesnotuniquelydeterminethedepth,thicknessorconductivityoftheocean.Todorequiresvariationsinthebackgroundfieldondifferenttimescales.SuggestedtimescalesaretheorbitalperiodofEuropa(sincethecurrentsheetvarieswithlocaltime)andharmonicsofthesynodicperiod(sincethefieldisnotperfectlysinusoidalinSystemIIIlongitude.)Howeverthereoscillationsareveryweakcomparedtothemain,11.2hourdrivingfield.
ItispossiblethatNeptune'smoon,Triton,alsocontainsanocean[RoadmapstoOceanWorlds,May2017.Archivedat:http://www.lpi.usra.edu/opag/ROW.Andreferencestherein.]ThepossibilityofobservingsuchanoceanhasbeenmentionedbySaur,etal.2010,andexaminedinmoredetailbyCaldwelletal.,submittedtoGRL,2017.ThemagneticsignaturediffersfromthatofEuropaintworespects.First,itisdrivenatalargenumberoffrequencies.TheinternalfieldofNeptuneiscomplex,withstrongquadrupoleandoctupoleterms,andtheorbitofTritonisinclined.Thisproducesvariationsinthebackgroundatthesynodicperiod,theorbitalperiod,harmonicsofthetwoandbeatfrequenciesofthetwo.Second,unlikeEuropa,theconductivityofTriton'satmosphereissignificantcomparedtothatoftheocean.Asaresult,Triton'sinducedfieldinvolvestwo,concentricconductinglayers.Inthisposter,weexaminethedetectabilityofsuchanocean,howpresenceofmultipleexcitingfrequenciesenhancesandcomplicatesstudiesoftheocean,andhowtheionosphereaffectssuchstudies.TheIonCompositionandDynamicsofSaturn’sEquatorialIonosphereasObservedbyCassiniCravens,T.E.,UniversityofKansasRenzaglia,A.R.,Moore,L.,Waite,Jr.,J.H.,Perryman,R.,Perry,M.,Wahlund,J.-E.,Persoon,A.,Kurth,W.S.
TheCassiniOrbitermadethefirstinsitumeasurementsoftheupperatmosphereandionosphereofSaturnduring2017.MeasurementsmadebytheIonandNeutralMassSpectrometer(INMS)foundmolecularhydrogenandheliumaswellasminorspeciesincludingwater,methane,ammonia,andorganics.TheINMSmeasuredseverallightionspecies(H+,H2
+,H3+,He+)andtheRadio
andPlasmaWaveScience(RPWS)instrumentmeasuredionosphericelectrondensities.Thecurrentpaperpresentsmeasurementsofthedaysideionosphericcompositionandaphotochemicalanalysisofthisdata.WeshowthatquantitativelyexplainingthemeasuredH+andH3
+densitiesrequiresheavymolecularspecieswitha.0001mixingratio,consistentwithINMSneutralcompositionmeasurements.Anempiricalphotochemicalanalysis,basedonINMSandRPWSmeasurements,suggeststhatthemajorionspecies(orsetofspecies)isheavyandmolecularwithashortchemicallifetimeneartheionosphericpeak.WealsopresentINMSdatafortheoneproximalorbitduringwhichanH+energyscanwasmade.Someionflowinformationwasobtainedandwecomparetheseresultswithasimpledynamicalmodelappropriateforhigheraltitudes.
30
![Page 31: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/31.jpg)
KineticsimulationsofelectronaccelerationbydispersivescaleAlfvenwavesintheJupitermagnetosphereDamiano,P.A.,GeophysicalInstitute,UniversityofAlaskaFairbanksDelamere,P.A.andStauffer,B.H.
RecentobservationsoftheJunosatellitehaveillustratedalargelybroadbandenergizedelectronsignatureathighlatitudes(e.g.Mauketal.,2017;Allegrinietal.,2017).Intheterrestrialmagnetosphere,signaturesofthisnaturearegenerallyattributedtoelectronenergizationbydispersivescaleAlfvenwaves(Alfvenwaveswithperpendicularscalelengthsontheorderoftheelectroninertial,ionacousticoriongyroradiusscalelengths).IntheJupitercontext,AlfvenwaveenergygeneratedintheIointeraction,orfromtransportmechanismsinthemagneto-disc,probablyreachesthesekineticscalelengthsviaaturbulentcascade.Inthispresentation,weuseahybridgyrofluid-kineticelectronsimulationmodelinadipolartopology(Damianoetal.,2007;2015)toinvestigateelectronenergizationbythesewavesatJupiter.Specifically,weconsiderthepropagationofdispersivescaleAlfvenwaves,sourcedintheIoplasmatorus,tohighlatitudesandhighlighttheresultingenergizedelectronsignatures-whicharealsobroadbandinnature.Weadditionallyinvestigatehowthedetailsofthisenergizationvarieswiththesteepnessofthetorusdensitygradientandthemagnitudeoftheion-to-electrontemperatureratio.TransientConfigurationsofSaturn’sDaysideHighLatitudeMagneticFieldDavies,E.H.,ImperialCollegeLondonMasters,A.;Hunt,G.J.;Sergis,N.;Dougherty,M.K.
AnoverviewoftheazimuthalstructureofSaturn’sdaysidemagneticfieldathighlatitudesispresented.DatafromtheentireCassiniMissionareusedtoillustratetheconfigurationofthefieldbeyondtheco-rotationlimit.Variabilityofthisconfigurationinbothspaceandtimeisdiscussed.TheconfigurationisshowntovarywithSaturnlocaltime,withdeviationofmagneticfieldfrommeridionalplanegreatesttowardstheduskanddawn.Inbothcases,thefieldisshowntosweeptowardsthetail,asweptbackconfigurationatdawnandasweptforwardconfigurationatdusk.Nosignificantvariationisfoundoverthedurationofthemission.Twocasestudiesarepresented,inthepre-duskandpost-dawnsectorsrespectively.Thefieldconfigurationisshowntoexhibittransientbehaviourinbothcases,withseveralexamplesofasuddensweepforwardshown.Atduskitissuggestedthatthesetransienteventsmayresultfromcompressionofthemagnetospherefollowingshocksinthesolarwind,usingdatafromtheMichiganSolarWindModel.Atdawnthesesignaturesareattributedtoreturnflowplasmafromtailreconnection,usingmagneticfieldandplasmadata.
31
![Page 32: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/32.jpg)
EntropyconstraintsonradialtransportinthegiantplanetmagnetospheresDelamere,P.,UniversityofAlaskaFairbanksX.Ma,B.Neupane,andB.Burkholder
Radialtransportinthegiantplanetmagnetodiscsisatwo-wayprocessthatresultsinnetmassoutflow.Itisgenerallyacceptedthatanegativeradialgradientinfluxtubemasscontentleadstoacentrifugally-drivenfluxtubeinterchangeinstability.However,thephysicaltransportmechanismscannotbeunderstoodwithoutconsideringmagneticfluxandinternalenergy(i.e.,entropy)transport.Magneticfluxmustbebalancedandapositivefluxtubeentropyprofilemustbemaintainedtoensurelong-termconvectivestability(justasaninvertedatmospherictemperatureprofileisconvectivelystable).Usingthermalplasmamoments[Thomsenetal.,2010],weexaminelocal(specific)andfluxtubeintegratedentropy,incombinationwitha2-Daxisymmetricmagnetodiscequilibriummodel[i.e.,Caudal,1986]toconstrainradialtransportprocesses.InidealMHD,specificandfluxtubeentropyareconservedquantities.Variationsindicate,forexample,non-adiabaticheatingand/orchangesinfluxtubeentropycontentviamagneticreconnection.AtSaturn,wefindthatspecificentropyincreasesfrom4Rstoroughly20Rs(whereRs=Saturn’sradius),suggestingnon-adiabaticheating.Beyond20Rsthemeanprofileisconstant,indicatingthatthetransportmechanismsmaybefundamentallydifferent.The2-Dmodelconfirmstheexpectedpositiveradialfluxtubeentropygradientnecessaryforstability.However,iffluxtubeinterchangemotioninvolvestheentirefluxtube(equipotentialmagneticfieldlines),thenentropywillbetransportedradiallyinward.Fromtheperspectiveoflong-termstabilitythiscannothappen.Insteadwesuggestthattransportlikelyinvolvespartialfluxtubeinterchangethroughadoublereconnectionprocess(non-equipotentialmagneticfieldlines)firstsuggestedbyMaetal.,[2016]fortheRayleigh-Taylor(RT)instability.Resultsfrom3-DRThybridsimulationswillalsobepresented.AtmosphericlossatIo,Europa;massloadingandioncyclotronwavesproductionDols,V.,LASPCUBoulderBagenal,F.;Crary.F
AtIoandEuropa,theinteractionoftheJovianplasmawiththemoonatmosphereleadstomassloadingofnewionsandsignificantlossesofneutralstospace.
Dependingontheirvelocity,someneutralswillbeejectedoutoftheJoviansystem;otherswillformextendedneutralcloudsalongtheorbitofthemoons.TheseextendedneutralcloudsareprobablythemainsourceofplasmafortheJovianmagnetosphere.Theyaredifficulttoobservedirectlythustheircompositionanddensityarestillpoorlyconstrained.Afuturemodelingoftheformationoftheseextendedcloudsrequiresanestimateoftheiratmosphericsources.
WeestimatetheatmosphericlossesatIoandEuropaforeachlossprocess(dissociationandcollisions)withamulti-specieschemistrymodel,usingaprescribedatmosphericdistributionconsistentwiththeobservations.
Wealsoestimatetheproductionofnewmolecularions(massloading),whicharepickedupbytheflowinaring-beamdistribution.ThisdistributionisthesourceofElectroMagneticIonCyclotron(EMIC)waves,whichhavebeendetectedclosetoIoandEuropabytheGalileospacecraft.ThisproductionrateisimplementedinaplasmahybridcodethatsimulatestheproductionofEMICwavealongflowlinesinteractingwiththemoon’sneutralatmosphere.
32
![Page 33: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/33.jpg)
Jupiter’sX-rayAuroraSpectra2016-2017Dunn,W.R.,UniversityCollegeLondonBranduardi-Raymont,G.;Ness,J-U.;Ray,L.C.;Gladstone,G.R.;Jackman,C.M.;Achilleos,N.;Gray,R.;Elsner,R.F.;Rae,I.J.;Yao,Z.;Grodent,D.;Bonfond,B.;Nichols,J.;Kraft,R.P.;Ford,P.G.;Rodriguez,P.
PolewardofJupiter’smainauroralemission,therearediversedynamicmulti-wavebandaurorae.ThemostenergeticphotonsobservedfromthisregionareX-rays.MostoftheseX-raysareproducedwhenhigh-energy(~10sMeV)ionscollidewithJupiter’satmosphere[Gladstoneetal.2002;Elsneretal.2005;Branduardi-Raymontetal.2007;2008].TheseX-rayemissionstypicallypulseandchangemorphology,intensityandprecipitatingparticlepopulationsfromobservationtoobservationandpoletopole[Kimuraetal.2016;Dunnetal.2016;2017;Jackmanetal.,inreview].Theaccelerationprocess/esthatallowJupitertoproduceX-raysremaintobeconfirmed,butprobablyinvolveacombinationofoutermagnetosphereprocessesandlocalaccelerationatthepole[Cravensetal.2003;Bunceetal.2004;Clarketal.2017;Paranicasetal.2018].Wepresentanoverviewof~100hoursofXMM-NewtonobservationsofJupiterfrom2016-17andfocusona40-hourcontinuousobservationfromJuly10-12th2017,duringJunoPJ7.Atthistime,weobservesignificantchangesintheX-rayaurorafromJupiterrotationtorotation.Amongstthesechanges,weobservetime-varyingauroralpulsationrates,whichchangefromanon-regularintervaltoregular10-13-min(40-45-min)Northern(Southern)auroralpulses.Wealsoobservetime-varyingaccelerations,withatransientpossiblesulphurXVlinesuggestingthattheionsmaysometimesprecipitatewithenergiesinexcessof64MeV[Kharchenkoetal.2008].Alongsidearangeofauroralsulphurandoxygenlinesthathavepreviouslybeenobserved[Elsneretal.2005;Branduardi-Raymontetal.2007;Dunnetal.2016],wealsofindspectrallinesthatarenotcataloguedasoxygenorsulphurlines,butareatknownwavelengthsforcarbonand/ornitrogenandmagnesium,suggestingthatthespeciesandabundancesoftheprecipitatingionpopulationsmaychangewithtimeand/orspace.Wefinishbytryingtoplacetheseresultsinthecontextofotherwavebandsandtheirpossiblephysicaldrivers.
33
![Page 34: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/34.jpg)
Jupiter'sX-rayAuroraDuringSolarMinimumDunn,W.R.,UniversityCollegeLondonW.R.Dunn,Branduardi-Raymont,G.;Elsner,R.;Gray,R.;FordP.;Gladstone,G.R.;Ray,L.;Jackman,C.;Achilleos,N.;Guio,P.;Nichols,J.;Ebert,R.;McComas,D.;Elliott,H.;Rae,I.J.;YaoZ.;Badman,S.;Kraft,R.
Jupiter’sNorthernandSouthernX-rayauroraeareeachdominatedbyaflaringpolarspot[Gladstoneetal.2002;Elsneretal.2005;Branduardi-Raymontetal.2004;2007a;Dunnetal.2016;2017].X-rayemissionlinespectrashowthatthesehotspotsareproducedbytheprecipitationofhigh-energy(~MeV/amu)ions.SlightlyequatorwardofeachhotspotthereisatransientauroralovalofhardX-raysthatareproducedwhenthoseprecipitatingelectronsthatalsogeneratetheUVmainemissionhavesufficientenergytoemitX-raybremsstrahlung(typicallywhentheyarerelativistic)[Branduardi-Raymontetal.2008].Thesolarminimumfrom2007-2009isthedeepestandlongestofthespaceage.Here,wepresentX-rayobservationsofJupiterduringFebruaryandMarch2007,whentheNewHorizonsspacecraftwasapproachingtheplanetandconductingin-situobservationsofthesolarwind.WefindthattheX-rayemissionfromJupiter'sequatorialregionsisexceptionallydimrelativetonon-solarminimumX-rayobservations.Thisisexpected,sincethelowsolarX-rayfluxwouldproducelowerlevelsofscatteredorfluorescedX-rays[e.g.Branduardi-Raymontetal.2007b].WealsofindthatduringthistimetheX-rayauroraisgenerallyverydim,butbrightens/dimsbyafactorof2fromobservation-to-observation.Duringthese6Chandraobservationsand4XMM-Newtonobservations,NewHorizonsmeasuredmultipleapproachesbytwoCorotatingInteractionRegions.Here,wecomparetheX-rayobservationswithboththeupstreamsolarwindmeasurementsfromNewHorizonsandthecontemporaneousHubbleSpaceTelescopeUVobservations[Nicholsetal.2009].Wefindcertainauroralemissionsappeartobetriggeredbysolarwindcompressionswhileothersseemindependent.WealsoconnectpulsatingUVpolaraurorawithsimilarX-rayemissions.
34
![Page 35: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/35.jpg)
ComparingElectronEnergeticsandUVBrightnessinJupiter'sPolarAuroralRegionEbert,R.W.,SouthwestResearchInstituteGreathouse,T.K.,Clark,G.,Allegrini,F.,Bagenal,F.,Bolton,S.J.,Gladstone,G.R.,Hue,V.,Levin,S.,Louarn,P.,Mauk,B.H.,McComas,D.J.,Paranicas,C.,Szalay,J.R.,Thomsen,M.F.,andWilson,R.J.
Todate,studiesofelectronobservationsfromJunoinJupiter’spolarauroralregion,theregionpolewardofJupiter’smainaurora,haveidentifiedmagneticfieldalignedelectronbeamsmovingawayfromtheplanet(upward)withnarrowenergydistributionsandmono-energeticpeaksbetween20keVand400keV[Ebertetal.,2017;Clarketal.2017],upwardelectronbeamswithMeVenergies[Mauketal.2017;Beckeretal.2017;Paranicasetal.2018]andbi-directional(upwardanddownward)electronbeamswithbroadenergydistributionsthatroll-overbetween~2–5keVandhaveapowerlawtailthatextenduptoatleast~100keV[Ebertetal.2017].Thedownwardbeamsassociatedwiththesebroadinenergyelectrondistributionsappeartorelatetoaprimarysourceofprecipitatingelectronsinthepolarauroralregion.PreliminaryanalysisbyEbertetal.2017showedthattheenergyfluxassociatedwiththesedownwardbeamsrangedfrom~0.1–5mWm-2,whichisexpectedtoproducebetween1–50kilorayleighs(kR)ofUVemissions.Thequestionofwhetherthesebeamscouldproducethebrighter(100sofkR)UVemissionsobservedinJupiter’spolarauroralregionremainsunanswered.Inanattempttoaddressthis,wepresentaquantitativecomparisonbetweentheelectronenergyfluxandtheUVbrightnessobservedneartheJunomagneticfootprintinJupiter’snorthernpolarauroralregionpriortoperijove5.WeuseobservationsfromtheJovianAuroralDistributionsExperimentElectronsensor(JADE-E;McComasetal.2017,JupiterEnergeticparticleDetectorInstrument(JEDI;Mauketal.2017)investigationandtheUltravioletSpectrograph(UVS;Gladstoneetal.2017)onJuno.WealsopresentastatisticalanalysisoftheenergyfluxassociatedwiththesebroadinenergydistributionsofdownwardelectronstoestimatetherangeinUVbrightnesstheyareexpectedtoproduce.
JUMPER:JUpiterMagnetosPhericboundaryExploreREbert,R.W.,SouthwestResearchInstituteAllegrini,F.,Bagenal,F.,Beebe,C.,Dayeh,M.A.,Desai,M.I.,George,D.,Hanley,J.,Mokashi,P.,Murphy,N.,Valek,P.W.,Wenkert,D.,Wolf,A.,andYen,C.-w.L.
TheSouthwestResearchInstitute(SwRI),incollaborationwithNASA’sJetPropulsionLaboratory(JPL)andtheUniversityofColorado’sLaboratoryforAtmosphericandSpacePhysics(CU/LASP),hasdevelopedtheJUpiterMagnetosPhericboundaryExploreR,orJUMPER,missionconcept.JUMPER’sscienceobjectivesfocuson(1)howthesolarwindinfluencestheglobalstructureanddynamicswithinthemagnetosphereand(2)interactswithJupiter’smagnetosphericboundaries,and(3)determiningthecontributionofenergeticneutralatoms(ENAs)tomasslossfromtheJovianspaceenvironment.Thesescienceobjectivesaremetwithaninstrumentpayloadconsistingofaplasmasensor,amagnetometer,andaneutralatomimager.MeasurementsfromtheseinstrumentswillcomplementsimultaneousobservationsofJupiter’smagnetosphere,radioemissions,and/oraurorafromaJupiter-orbitingspacecraftand/orEarth-basedobservatories,providingsimultaneous,multi-pointobservationstostudythissystem.SupplementalscienceopportunitiesassociatedwithflybysofGalileansatellitesGanymedeandCallistoandmulti-pointobservationsinsideJupiter’smagnetospherearealsopossible.JUMPERwasselectedforfullmissionconceptdevelopmentthroughNASA’sPSDS3program.Thispresentationwilldiscussessomeofthedetailsofthismissionconceptstudy,focusingonJUMPER’sscienceinvestigation,scienceimplementationandinstrumentcomplement,missiondesign,spacecraftconcept,conceptofoperationsandtechnicalchallenges.
35
![Page 36: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/36.jpg)
Atwo-stepmechanismforacceleratingup-goingelectronsthroughoutJupiter’spolarcapregionviainteractionswithup-goingwhistler-modewavesElliott,S.S.,UniversityofIowaGurnett,D.A.,Kurth,W.S.,Mauk,B.H.,Valek,P.,Allegrini,F.,Connerney,J.E.P.,Bolton,S.J.
Electronsoverarangeofenergies(fromtensofkeVtoaboveoneMeVwithapproximatepowerlaw-likedistributions)havebeenobservedinassociationwithintenseup-goingwhistler-modewavesthroughouttheJovianpolarregions.Boththeelectronsandthewavesaretravelingupwardsandarestronglycorrelatedwithoneanother,indicativeofwave-particleinteraction.Theenergyfluxofthewhistler-modewavesiscomparabletotheenergyfluxoftheenergeticelectrons(upto0.24W/m^2inthepolarcap).Thissuggeststhatthewhistler-modewavesinteractwiththeelectrons,providingacandidateaccelerationmechanism.Weproposethatthismechanisminvolvesatwo-stepprocess.First,acurrent-drivenparallelelectricfieldiscreatedinregionsoflowdensityandconvergingmagneticfieldlines,wheretheplasmacannotcarrythedownwardcurrent,therebygeneratinganelectronbeam(i.e.aninverted-V).Thisbeamdrivesanelectron-beam-plasmainstability,generatinglarge-amplitudewhistler-modewavesoverabroadfrequencyrange.Second,thesewavesarethendampedastheymovetohigheraltitudes,acceleratingtheelectronsandleadingtoabroadrangeofelectronenergiesviaastochasticprocess.Byanalyzingabeamdistributionfunction,thegrowthrate(gamma)isshowntoswitchfrombeingpositive(wavegrowth)tonegative(wavedamping,electronacceleration)whenthephasevelocityofthewaveexceedstheelectronbeamvelocity.Wethereforeproposethatwavesaregeneratedatlowaltitudesandmovetohigheraltitudes,increasingtheirphasevelocityandexceedingthebeamvelocity,dampingthewavesandacceleratingtheelectrons.Saturn’sPlasmaDensityDepletionsAlongMagneticFieldLinesConnectedtotheMainRingsFarrell,W.M.,NASA/GoddardSFCHadid,L.Z.,Morooka,M.W.,Kurth,W.S.,Wahlund,J.-E.,MacDowall,R.J.,Sulaiman,A.H.,Persoon,A.M.,andGurnett,D.A.
WereportonasetofclearandabruptdecreasesinthehighfrequencyboundaryofwhistlermodeemissionsdetectedbyCassiniathighlatitudes(about+/-40o)duringthelowaltitudeproximalflybysofSaturn.TheseabruptdecreasesordropoutshavestartandstoplocationsthatcorrespondtoL-shellsattheedgesoftheAandBring.Langmuirprobemeasurementscanconfirm,insomecases,thattheabruptdecreaseinthehighfrequencywhistlermodeboundaryisassociatedwithacorrespondingabruptelectrondensitydropoutoverevacuatedfieldlinesconnectedtotheAandBrings.Widebanddataalsorevealelectronplasmaoscillationsandwhistlermodecutoffsconsistentwithalowdensityplasmaintheregion.Theobservationoftheelectrondensitydropoutalongring-connectingfieldlinessuggeststhatstrongambipolarforcesareoperating,drawingcoldionosphericionsoutwardtofillthefluxtubes.Thereisananalogwiththerefillingoffluxtubesintheterrestrialplasmasphere.Wesuggestthering-connectedelectrondensitydropoutsobservedbetween1.1and1.3RsareconnectedtothelowdensityringplasmacavityobservedovertoptheA-Bringduringthe2004Saturnorbitalinsertionpass.
36
![Page 37: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/37.jpg)
SKR:Arotatingradiosourcethatappearsclock-likeFischer,G.,AustrianAcademyofSciencesYe,S.-Y.
TheclassicalpictureofSaturnKilometricRadiation(SKR)fromtheVoyagereraisthatofaclock-likeradiosourcewhosephaseisindependentofthepositionoftheobserver.ThispicturehasbeenmodifiedintheCassiniera:Theexistenceofrotatingmagneticfieldperturbationsimpliestheexistenceoftworotatingcurrentsystems(oneforeachhemisphere),suggestingthatthesecurrentsystemsalsocauserotatingmodulationsinthenorthernandsouthernSKRemissions.RotatingSKRsourceshavebeenshowntoexist,butthedominanceoftheintenseSKRsourcesinthemidmorningsectorgivesrisetoaclock-likemodulationoveracertainlocaltimerangeoftheobservingspacecraft.ItisthisdominancethatmakesmostSKRappearclock-like.
Adistinctionbetweenclock-likemodulationandarotatingsourcecanbemadewhentheobservingspacecrafttraversesoveralargeregioninlocaltimewithinashorttime,i.e.duringperiapsispasses.InthispresentationwewilllookattheCassiniperiapsispasses(takingplaceatvariouslocaltimes)andplottheSKRintensityasafunctionofsub-solarlongitudeandasafunctionofsub-spacecraftlongitudetoseewhichkindoflongitudesystemorganizestheSKRdatainabetterway.
CombinedJunoobservationsandmodelingoftheJovianauroralelectroninteractionwiththeJovianupperatmosphereGérard,J.-C.,UniversitédeLiègeB.Bonfond,G.R.Gladstone,F.Allegrini,D.Grodent,T.K.Greathouse,V.Hue,M.H.Versteeg,S.Bolton,J.E.P.Connerney,S.M.Levin
TheJunomissionprovidesauniqueopportunityduringeachperijovepasstosamplethedownwardelectronfluxatspacecraftaltitudewhileobservingfarultravioletH2andinfraredH3
+emissionsatJuno’smagneticfootprint.Inaddition,theratiooftheH2spectralbandabsorbedbyhydrocarbonstotheunabsorbedportionofthespectrum(FUVcolorratio)isoftenusedasaproxyforthedepthofthepenetrationofenergeticelectrons(relativetothehydrocarbonhomopause).TherelationshipbetweenthecolorratioandtheelectronpenetrationhasbeensimulatedwithaMonteCarlomodelsolvingtheBoltzmanntransportequation.AnalysisofconcurrentFUVandIRimagesobtainedduringthefirstperijove(PJ1)suggeststhattheratioofH3
+radiancetoH2unabsorbedemissionismaximalinregionswithlowFUVcolorratio.ThisresultsuggeststhatpartoftheH3
+columnislostinreactionswithmethanewhichconvertsH3
+intoheavierions.WealsoexaminetheobservedrelationshipbetweenthedetailedmorphologyoftheultravioletstructuresandoftheassociatedUVcolorratio,thetotaldownwardelectronenergyfluxanditsspectralcharacteristics.
37
![Page 38: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/38.jpg)
Jupiter'sUltravioletAurorasGladstone,G.R.,SwRI
Ashortreviewoffar-ultraviolet(FUV,100-200nm)observationsandmodelsoftheJovianauroraispresented.AlthoughJupiter’sFUVaurorawasunambiguouslydiscoveredbytheultravioletspectrometer(UVS)onVoyager1in1979,sub-orbitalFUVrocketspectrahadhintedataurorasadecadeearlier.Detailedphysicalmodelsoftheexpectedemissionswerepresentedasearlyas1973.Sincethosetimesourobservationalandmodelingcapabilitieshavedevelopedremarkably,althoughourunderstandinglagsfarbehind.Aswithmostgreatimprovementsindata,therecentastonishingobservationsbyJunohelpsolveafewlongstandingproblemswhilepresentingseveralnewones.AUranus-likemagnetosphereinamagnetizedSolarWind:solsticeandequinoxconfigurationsGriton,L.,LESIA-ObservatoiredeParisPantellini,F.
WepresentMHDsimulationsofafastrotatingplanetarymagnetospherereminiscentoftheplanetUranusatsolstice,i.e.withthespinaxispointingtotheSun,andatequinox.WeimposeatentimesfasterrotationthanforUranus,inordertoemphasizetheeffectsofrotationonthemagnetospherictailwithouttheneedofanexcessivelylargesimulationdomainwhilekeepingthequalitativeaspectsofasupersonicmagnetizedsolarwindinteractingwithafastrotatingmagnetosphere.WefindthatacomplexhelicalAlfvénicstructurepropagatesdownstreamatavelocityexceedingtheplasmavelocityinthemagnetosheath.Similarly,thereconnectionregions,whichmediatetheinteractionoftheplanetarymagneticfieldandtheinterplanetarymagneticfield(IMF),doalsoformahelicalstructurewiththesamedowntailvelocitybutatwotimeslargerpitch.WespeculatethatthemagneticfieldofthehelicalstructureconnectedtotheIMFasymptoticallyreducethephasevelocityofthehelicalstructuretowardsthetailwardplasmavelocityinthemagnetosheath.WecompareoursimulationresultswithpreviousstudiesofUranus'magnetosphere,bothforthesolsticeandequinoxconfigurations.
38
![Page 39: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/39.jpg)
Jupiter’smesmerizingauroralshow;HSTultravioletobservationsnearandfarfromJunoperijovesGrodent,D.,UniversitédeLiège,STARInstitute,LPAPYao,Z.,Bonfond,B.,Palmaerts,B.,Dumont,M.,Gérard,J.C.,Radioti,A.,Gladstone,G.R.,Mauk,B.,Connerney,J.E.P.,Nichols,J.D.,Bunce,E.J.,Roth,L.,Saur,J.,Kimura,T.,OrtonG.S.,Badman,S.V.,McComas,D.,Kurth,S.K.,Adriani,A.,Valek,P.W.,Delamere,P.,Bagenal,F.
Aftera6-monthperiodduringwhichtheseparationanglebetweentheSunandJupiterwastoosmalltopermitobservationswithEarthorbittelescopes,operationoftheHubbleSpaceTelescope,supportingtheJunomission,wasresumed(almost)intimeforPJ11.WebrieflyreviewthemainresultsofthepreviouspartofthisHSTcampaign,coveringPJ03toPJ07.WethenpresentthenewestresultsobtainedduringPJ11,PJ12andPJ13.MostoftheobservingtimeallocatedtothisHSTcampaignwasusedduringthefirstpartofthecampaignandallowedustosampleJupiter’saurora,notonlynearJuno’sperijoves,butalsoduringtheweekbeforeandtheweekaftereachperijove.Duringthesetimesawayfromperijove,HST-STISwasthesoleinstrumentabletoprovidehighspatialandhightemporalresolutiondynamicimagesofJupiter’sFUVaurora,whichcanbecomparedwithmeasurementsfromJuno’sinsituinstruments.Insteadofpresentingastatisticaloverviewofthedata,wehaveamoredetailedlookatsomespecificfeaturesrevealedbytheasyetunsurpassedSTIScamera.Inparticular,weidentifydistinctiveauroralphenomena,likeexplosivebrighteningspolewardofthemainauroralemission.Wepresentonesuchevent,whichwelinktoastrongperturbationofthemagneticfieldandoftheenergydistributionoftheplasmaparticlesconcurrentlyobservedwithJuno.Wesuggestthatthecharacteristicsandthetimingofthisperturbationandofitsassociatedauroralsignatureareconsistentwithareconnectionevent.
EffectsoftheSizeScaleontheDynamicsofTrappedChargedParticlesinGasGiantMagnetospheresGuio,P.,PhysicsandAstronomy/UCL/UnitedKingdomAchilleos,N.andArridge,C.
Thespatialandtimecharacteristicsoftrappedchargedparticletrajectoriesinmagnetosphereshavebeenextensivelystudiedusingdipolemagneticfieldstructures.Werecentlyextendedthesecalculationsforchargedparticletrappedina'disc-like'fieldstructureassociatedwiththegasgiantrotation-dominatedmagnetosphereasdescribedbytheUCL/Achilleos-Guio-Arridge(UCL/AGA)magnetodiscmodel.
Inthisstudy,wepresentcalculationsforappropriaterangeofsizescalesforobservedgiantplanetmagnetospheres,characterisedprimarilybythedistanceofthemagnetopauseboundarytotheplanet,or`standoffdistance'ausefulproxyfortheoverallsystemsize.Wediscusstheeffectsofthesizescaleofthemagnetosphereonvariousparticleparameters,andcomparewithotherfieldmodelsforsuchmagnetodiscdominatedmagnetospheres.
39
![Page 40: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/40.jpg)
Saturn’sionosphere:ElectrondensityaltitudeprofilesandringshadowingeffectsfromtheCassiniGrandFinaleHadid,L.Z.,SwedishInstituteofSpacePhysics,Box537,SE-75121Uppsala,SwedenMorooka,M.W.,Wahlund,J.E.,PersoonA.M.,Andrews,D.J.,Shebanits,O.,Kurth,W.S.,Edberg,N.J.T.,Vigren,E.,NagyA.F.,Moore,L.,Cravens,T.E.,Hedman,M.M.,Farrell,W.M.,Eriksson,A.I.
WepresenttheelectrondensityaltitudeprofilesofSaturn’sionosphereatequatoriallatitudes(−15o≤φ≤15o)andtheringshadowingeffectsfromallthe23proximalpassesofCassini’sGrandFinale.ThedataarecollectedbytheLangmuirprobe(LP)andforsomecasesfromtheplasmawavefrequencycharacteristicsoftheRadioandPlasmaWaveScience(RPWS)investigation.Ahighdegreeofvariabilityintheelectrondensityprofilesisobserved.However,organizingthembyconsecutivealtituderangesrevealedcleardifferencesbetweenthesouthern(winter)andnorthern(summer)hemispheres.WeshowalayeredelectrondensityaltitudeprofilewithevidenceinthesouthernhemisphereofanelectrodynamictypeofinteractionwiththeplanetsinnermostDring.SimilarlayerswereobservedduringtheFinalPlungeofCassini,wherethemainionosphericpeakiscrossedat~1550kmaltitude[Hadidetal.submitted,2018a].
Moreover,fromtheringshadowsignaturesonthetotalioncurrentcollectedbytheLP,wereproducetheAandBringboundariesandconfirmthattheyareopticallythickerthantheinnerCandDringsandtheCassiniDivisiontothesolarextremeultravioletradiation.Furthermore,observedvariationswithrespecttotheinneredgeoftheBringshadowimplyadelayedresponseoftheionosphericH+becauseofitslonglifetimeand/orsuggestthepresenceofring-derivedplasmafromtheCandDringsreducingtheshadowingsignatures[Hadidetal.submitted,2018b].ChargedparticleinjectionsathighJovianlatitudesHaggerty,D.K.,JohnsHopkinsUniversityAppliedPhysicsLabB.H.Mauk,C.Paranicas.Clark,P.Kollmann,A.Rymer,S.Bolton,J.E.P.Connerney,S.Levin
ChargedparticleinjectionsarecommonlyobservedinJupiter'smagnetosphere.LowenergyparticlesarecarriedinwardtowardJupiter,whilemoreenergeticparticlescandriftlongitudinallyoutoftheinjecteddistribution.Iondriftinthesamedirectionasplasmacorotationandelectronsdriftintheoppositedirection.Becauseofthegradient-curvaturedrift,aspacecraftmeasuringthesedistributionswilloftenseeavelocitydispersiveeventwithhigherenergyionsfirst,followedbylowerenergyions,thenlowerenergyelectrons,andfinallyhigherenergyelectrons.TheJunospacecraftprovidesauniqueopportunityasthefirstpolarorbiterofJupitertostudyinjectioneventsfromhighlatitude.WhileinjectionshavebeenobservedinmultipleplacesalongtheJunoorbit,thestrongestandbestresolvedregionofinjectionsisinthenorthernradiationbeltpriortothenorthpolarpass.Inthisreportwedescribetheobservations,showhowtheyevolveasafunctionofdecreasingradialdistance,andreportonasimplemodeltodescribetheevents.
40
![Page 41: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/41.jpg)
ThesignificanceofSaturnring-iceinCassiniproximalobservations.Hamil,O.Q.,UniversityofKansasCravens,T.E.,Sakai,S.,Reedy,N.L.
TheringsofSaturncancontributebothmaterial(i.e.water),andenergytoitsupperatmosphereandionosphere.Ionosphericmodelsrequirethepresenceofmolecularspeciessuchaswaterthatcanchemicallyremoveionosphericprotons,whichareotherwiseassociatedwithelectrondensitiesthatgreatlyexceedthosefromobservation.Thesemodelsadopttopsidefluxesofwatermolecules.OthermodelshaveshownthaticegrainsfromSaturn'sringscanimpacttheatmosphere.Inthecurrentwork,weexaminethemechanicsofwaterandenergydepositiontotheupperatmosphere.Specifically,wemodelhowicegrainsdepositbothmaterialandenergyinSaturn'supperatmosphereasafunctionofgrainsize,initialvelocity(atthe"top"oftheatmosphere,definedatanaltitudeabovethecloud-topsof3000km),andincidentangle.Typicalgrainspeedsareexpectedtoberoughly10-20km/s.Grainswithradiiontheorderof1-10nmdepositmostoftheirenergyinthealtituderangeof1200-1500km,andcanvaporize,contributingwatervaportotheupperatmosphere.
DatafromCassiniindicatethepresenceoficegrainsontheorderof40,000amu.Grainsofthissizedonotablateinourmodel,butweexploretheirenergydepositionandterminalvelocityasafunctionofgraindensitiesspanningarangerepresentativeoftightlypackedsphericalgrains,downtolooselyconfinedsnowflaketypeobjects.Further,wemodelvolatileorganicgrains,representedherebymethane/CO2,todeterminetheinitialgrainparametersrequiredtoaccountforobservationsofthesespeciesintheupperatmosphere.Towardsaself-regulatingmagnetopausemodelwithapplicationtoSaturnHardy,F.,UniversityCollegeLondonAchilleos,N.,Guio,P.
Wereportworkinprogressontheconstructionofanumericalmodelforamagnetopauseboundaryusingthelocalpressurebalancebetweenthesolar-winddynamicpressureandthemagneticpressureduetotheplanetaryfield.WewillapplythismethodtoSaturninordertoillustratethefollowingpoints:
-awell-posedformulationoftheproblemcanbeusedtosolvethepressurebalanceinthenoon-midnightmeridianplane.Thisapproachshedslightonthenatureofthecharacteristicpolarcusp;itspositioncanbefoundaccuratelyandisconsistentwithMeadandBeard’s(1964)numericalresults.
-discretisationtechniquescoupledwithaNewton-Raphsonmethodcanbeusedtomapanon-axisymmetricsurfaceonwhichthemaximumerrorfromexactforcebalanceliesaround5percent.
-theintroductionofinternalplasmapressure‘regularises’theproblemandleadstoamagnetopausesurfacewithlocalresidualsnogreaterthanafewpercent.
WewillalsodiscussthefutureprospectsofthisstudyanditspotentialapplicationstotheconstructionofacomprehensivemodelforSaturn’smagnetopause.
41
![Page 42: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/42.jpg)
QuantifyingtheaccessofJupiter’smagnetosphericplasmatoEuropa’ssurfacethroughamulti-fluidMHDmodelHarris,C.D.K.,UniversityofMichiganJia,X.;Slavin,J.A.;Toth,G.;Rubin,M.
Europa’sspaceenvironmentiscontrolledbythewobblingofJupiter’smagneticfield,themagneticresponsetothiswobblinginducedintheconductingsubsurfaceocean,andtheinteractionofJupiter’smagnetospherewithEuropa’sionosphereandextendedexosphere.Wehavedevelopedamulti-fluidMHDmodelforEuropa’splasmainteractionwhichself-consistentlysolvesforthebulkpropertiesof3ionfluids(magnetosphericO+andionosphericO+,O2
+)andtheelectromagneticfieldsinthevicinityofthemoon.Tovalidateourmodel,wehavesimulatedtheGalileoE4andE17Flybysusingtheobservedplasmaandmagneticfieldconditions.OurmodelhasreproducedGalileomagnetometerobservationsandprovidesfull3Ddensityandvelocityfieldsfortheionfluidsduringeachflyby.Basedonthethree-ion-fluidMHDmodel,wehavemappedthedistributionofthemagnetosphericplasmathatwasabletopenetratetheplasmainteractiontoreachEuropa’ssurface.Wefindthatwhilethemajorityofdownwardfluximpingesontheupstreamhemisphere,thesurfaceimpactbytheambientmagnetosphericO+ionsexhibitsaslightpreferencetowardstheanti-jovianhemisphereduetotheinfluenceoftheconvectionalelectricfield.UndertheE4flybyconditions,justafractionoftheavailableupstreamO+ionsprecipitatetoEuropa’ssurface.Mostoftheambientplasmaisinsteaddivertedaroundthemoonduetotheplasmainteractionwiththeionosphere.ThisprecipitationrepresentsthecontributionofthermalplasmatothesputteringinteractionwithEuropa’sicysurfacewhichreplenishestheO2exosphere.CassiniUVISdetectsenergeticelectronsanddustintheSaturnsystemHendrix,AmandaR.,PlanetaryScienceInstituteEsposito,L.W.,Brooks,S.,Hansen,C.J.,Colwell,J.E.,Pryor,W.,McClintock,W.E.,Holsclaw,G.M.,Roussos,E.,Paranicas,C.,Kollmann,P.,Ye,S.
ThroughouttheCassinitouroftheSaturnsystem(2004-2017),theUltravioletImagingSpectrograph(UVIS)observationsoftheplanet,ringsandmoonswereaffectedtovaryingdegreesby“background”signal(noise)inboththeEUVandFUVchannels.Thisnoisewasgenerallysubtractedoffinordertostudythetargetsofprimaryinterest.Now,weinvestigatethisbackgroundandutilizeittounderstandmagnetosphericaspectsoftheSaturnsystem.Weassessthebackgroundnoiseanditsvariationsthroughoutthetour:wecomparewithheightabovetheringplane,withdistancefromSaturn,andwithtimeofdaytounderstandthesourcesofthenoise.WefindthatthemostdominanttrendisbackgroundlevelwithdistancefromSaturn:withinSaturn’sintenseradiationbelts,between~5-6Rsand~2.7-2.8RsUVISobservesanincreaseinbackgroundwithdecreasingRs;closetothemainrings,inwardof~2.7Rsthebackgrounddrops.ThistrendisconsistentwithMIMIobservationsofenergeticparticlesintheradiationbeltsandappearstobemoreconsistentwithMeVelectronsthanprotons.EvenforradiationinstrumentslikeMIMIitcanbechallengingtodisentanglethecontributionfromdifferentspeciesandenergiestoinstrumentcountrates.AddinginformationfromtheUVISbackgroundsthereforemayhelptounderstandtheaveragestateandtimeevolutionofSaturn’selectronradiationbelt.Insomeconfigurations,dustalsocontributestotheUVISbackground,superimposedontheelectronsignatures,asindicatedbycomparisonswithRPWSdata,sensitiveto~1microndustgrains.WeconcludethatMeVelectronspenetratethewallsoftheUVISinstrument,andthatdustenterstheinstrumentapertureinsomegeometries,impingingonthedetectorandcreatingaphoton-likesignal.TheUVISthusprovides,inadditiontotheinsituinstrumentsonCassini,afurthermeasurementofenergeticelectronsanddustintheSaturnsystem.
42
![Page 43: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/43.jpg)
InvestigatingDeflectionofJovianBulkPlasmabyEuropa’sIonosphereusingGalileoPlasmaDataHeuer,S.V.,JohnsHopkinsAppliedPhysicsLaboratoryRymer,A.M.,Westlake,J.H
ElectrodynamicinteractionsbetweenEuropa’sionosphereandJupiter’sco-rotatingplasmadecelerateanddeflectthebulkplasma,whichsubsequentlyacceleratesinthewakeofthemoon[Sauretal.,1998].ThedeflectionhasbeenmeasuredinsitubytheGalileoPlasmaScienceInstrument(PLS)[Patersonetal.,1999].WehaveproducedGalileoPLSionsensorenergyspectrogramsforallEuropaflybys(includingseveralpreviouslyunpublished)fromthefullresolutionplasmadatavolumeavailableonPDS.OuranalysishasrevealedsubstantialdeflectionofthebulkplasmawhichcouldpotentiallybeusedtoimprovebestestimatesforconstraintsoncertainpropertiesofEuropa’sexosphereandimproveinputstoMHDsimulationsofEuropa’sinteractionwiththeJovianmagnetosphereandplasmatorus.RadioJoveCitizenSciencePartnershipsHiggins,C.,MiddleTennesseeStateUniversityFung,S.,Thieman,J.,Garcia.L.
TheRadioJoveProject(radiojove.gsfc.nasa.gov)hasbeenoperatingasaneducationalactivityfor20yearstopromoteradioastronomytostudents,teachers,andthegeneralpublic.RadioJovehasrecentlypartneredwiththeNASASpaceScienceEducationConsortium(NSSEC)toworkwithinterestedamateursandpartnerinstitutionstoestablishradiospectrograph(15-30MHz)andsingle-frequency(20MHz)stationsforcitizenexplorationandscienceprojects.Thesestationswillhelpbuildalargeramateurradiosciencenetworkandincreasethespatialcoverageoflong-wavelengthradioobservationsacrosstheUS.
WewilloverviewthepartnershipsanddisplaycitizenobservationsofJupiterdecameteremission,theAugust2017solareclipse,ionosphericscintillationoftheCas-Aradiosource,andinterestingterrestriallightningevents.Inmanycasestheseobservationscompareverywellwithprofessionalradioobservatories.RadioJovealsosupportstheJunoMissionradiowavesinstrumentatJupiterbyusingcitizenscienceground-baseddataforcomparison.ThesedataarebeingarchivedatthePlanetaryDataSystem(PDS)archiveandthroughtheVirtualEuropeanSolarandPlanetaryAccess(VESPA)archiveforusebytheamateurandprofessionalradiosciencecommunity.
43
![Page 44: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/44.jpg)
LWA1ObservationsofJupiter’sLeft-HandPolarizedDecametricEmissionHiggins,C.,MiddleTennesseeStateUniversityClarke,T.E.,Imai,K.,Imai,M.,Reyes,F.,Thieman,J.
TheLongWavelengthArrayStation1(LWA1)inSocorro,NM,USA,providesfullStokesparametersand5kHzspectraland0.21mstemporalresolutionofJupiter’sdecametricradioemissionsoverthebandwidthof10-40MHz.LWA1observationsofJupiterfrom2012-2016wereusedtoshownewdetailsregardingJupiter’semissionstructure(Clarkeetal.,2014,2017),modulationlanestructures(K.Imaietal.,2017),and,inpart,thebeamconethickness(M.Imaietal.,2016).
JupiterhasmanyIo-relateddecameterradioemissionsources,andaccordingtotheoreticalmodels,thewell-knownsourcesIo-AandIo-Bemitfromthenorthernhemispherewithright-hand(RH)circularlypolarizedsignatures,andIo-CandIo-Demitfromthesouthernhemispherewithleft-hand(LH)polarization.InadditiontotheotherLWA1results,Higginsetal.(PRE8Proceedings,2017)showedthattheIo-Dradiosourcehassomepreviouslyunknownmorphologyandfinespectralstructures.RecentstudiesoftheIo-CsourceshowsimilarandinterestingLHspectralsignaturessuchasS-bursts,narrowbandN-events,S-Neventinteractions,andspectralarcsplitting.WehighlighttheIo-CobservationsandcomparethemwithIo-DeventstobetterunderstandmagneticinteractionsintheJoviansouthernhemisphere.VariationincompositionandtemperatureofplasmasintheIoplasmatorusconfirmedbytheHisaki/EXCEEDobservationHikida,R.,UniversityofTokyoYoshioka,K.,Murakami,G.,Kimura,T.,Tsuchiya,F.,andYoshikawa,I.
Previousobservations,conductedbyground-basedtelescopesandspacecraftsuchasVoyagerandCassini,haveshownthatcomposition,temperature,anddensityofthecoreplasmasintheIoplasmatorus(IPT)varyinaccordancewiththesurroundingenvironment,suchasvolcanicactivityonIoandmagnetosphericcondition.However,thetimevariationindensityofhotelectrons(~100eV)hasnotbeeninvestigated,althoughtheyplayanimportantroleinenergybudgetoftheIPT.Thisstudyprovidesthefluctuationofhotelectroncomponent.WeappliedthespectraldiagnosismethodtotheEUVspectraobtainedbyEXCEEDonHisakisatellite.ThedatasetfromJan.2014toApr.2014,fromNov.2014toMay.2015,andfromDec.2015toAug.2016wereused.Thefollowingtworesultswereobtained.First,theincreaseinhotelectrondensityinaccordancewiththeincreaseinvolcanicactivitywasconfirmed.WhileHisaki/EXCEEDobservedtheIPT,severalexplosionsofvolcanoesoccurredin2015and2016.TheincreaseinhotelectrondensityisconsistentwiththeactivationofinterchangemotionswhichcanbeassociatedwiththeincreaseingassupplyamounttotheIPT.Second,wefoundthatsometransientbrighteningsoftheIPTwhichfollowtheauroralbrightenings wereduetotheincreaseinhotelectrondensity.ThisresultindicatestheexistenceoftheinwardflowofhotelectronstowardtheIPTfromthedistantregion(magneticallyconnectedtothepolarregion).
44
![Page 45: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/45.jpg)
A4DModeloftheIoPlasmaTorusHinton,P.,UniversityofColoradoBagenal,F.
Jupiter’smoonIovolcanicallyoutgassesroughly1000kg/sofneutralatomsthat,throughvariousionizationmechanisms,endupasplasmainJupiter’smagnetosphere.Thisplasmathenbecomesdistributedalongmagneticfieldlinesandassumesanoveralltoroidalstructure.WeuseadiffusiveequilibriummodeltoquantifythestructureoftheIoplasmatorus(IPT).ThedifferentsectionsoftheIPTincludethecoldinnertorus(disk),aportionbetweenthediskandtheorbitofIo(ductorsometimescalledtheribbon),andtheremainingwarmeroutertorus(donut).Thediskexistsfromapproximately4-5.6RJ,theductexistsfrom5.6-6RJ,andthedonutportionextendsfrom6-10RJ,whereRJistheradiusofJupiter(1RJequals71,492km).Inadditiontogeneratingamodelthatcapturesthesedimensions,ourmodelalsoaccountsforlocaltimevariation,mostlyincomposition,observedbyCassini.This4Dmodelincludesvariousparametersthatcanbeadjustedinordertogainfurtherinsightintotheplasmatorus.Suchparametersincludeionandelectrontemperatures,densities,anddistributions,aswellasJupiter’smagneticfield.UsingthismodelwecalculatehowfastAlfvenwavestravelthroughtheIPT.WemakepredictionsaboutthelocationoftheIoauroralfootprint(IFT)whichwillultimatelybecomparedwithJuno’sobservations.Additionally,wecalculateandanalyzetheAlfvenpowergeneratedbyIoasitorbitsinJupiter’smagneticfield.
ChargedDustDynamicsatJupiterandSaturnHoranyi,Mihaly,LASPandPhysics,U.ofColorado
Themotionofchargeddustparticlescanbestronglyinfluencedbymagnetosphericelectricandmagneticfields.ThereareseveralobservationsbothatJupiterandSaturnthatcanbebestexplainedbyrecognizingthisstronginteractionbetweenmagnetosphericfieldsandplasmas,andfaintdustrings.ThistalkwillfocusonrecentobservationsbyJuno,asitrepeatedlycrossedJupiter’sringplane,theCassini’sobservationsofthevariousmoonsembeddedintheE-ringofSaturn,andconcludewithpredictionsforthedustobservationsbytheupcomingClippermissiontoJupiter.
45
![Page 46: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/46.jpg)
JunoObservationsofPlasmaWavesAssociatedwiththeIoFootprintTailHospodarsky,G.B.,UniversityofIowaKurth,W.S.,Elliott,S.S.,Gurnett,D.A.,Averkamp,T.F.,Szalay,J.R.,Allegrini,F.,Bonfond,B.,Clark,G.,Connerney,J.E.P.,Ebert,R.W.,Gladstone,G.R.,Bolton,S.J.,Levin,S.M.,Mauk,B.H.andValek,P.
TheJunospacecrafthascrossedmagneticfluxtubesassociatedwiththeIoauroralfootprinttailatavarietyofdowntaildistancesfromtheIofootprintspot.TheJunoradioandplasmawaveinstrument(Waves)detectslargeamplitudeelectromagneticwavesduringmanyofthesecrossings.TheseemissionsareusuallydetectedforjustafewsecondstotensofsecondsandhighresolutionWaveburstdatashowthatpeakamplitudesofthesewavescanreachabout1V/mfortheelectricfieldandafewnTforthemagneticfield.However,ontherecentperijove12northerncrossing,theWavesinstrumentdetectedanintensefunnelshapedemissionlastingformanyminuteswithintenselowerfrequencyemissionatthefunnelapex.InitialanalysisoftheseemissionssuggestthatthesewavesarepropagatingupwardfromJupiter.Theemissionfrequenciesarewellbelowtheelectroncyclotronfrequencyandtheupperfrequencyappearstobecutoffattheelectronplasmafrequency,withanadditionalchangeinintensityalsoobservedattheprotoncyclotronfrequency.Wewilldiscussthedetailsofthesewavesandexaminepossiblewavemodes.ModelingofJovianAuroralPolarIonandProtonPrecipitationHouston,S.J.,DepartmentofPhysicsandAstronomy,UniversityofKansas,Lawrence,Kansas,USA.Cravens,T.E.,Schultz,D.R.,Mauk,B.H.,Haggerty,D.K.
Auroralparticleprecipitationdominatesthechemicalandphysicalenvironmentoftheupperatmospheresandionospheresoftheouterplanets.PrecipitationofenergeticelectronsfromthemiddlemagnetosphereisresponsibleforthemainauroralovalatJupiter,butenergeticelectron,proton,andionprecipitationtakeplaceinthepolarcaps.AtleastsomeoftheionprecipitationisassociatedwithsoftX-rayemission.EnergeticionmeasurementsfromNASA’sspacecraft,Juno,haveyettomeasureionfluxescapableofproducingtheobservedX-rays.WepresentamodelofthetransportofmagnetosphericoxygenionsastheyprecipitateintoJupiter’spolaratmosphere,indicatingthatX-rayemissionbeginsoccurringaslowas0.2MeV/u.WehaverevisedandupdatedthehybridMonteCarlomodeloriginallydevelopedbyOzaketal.,2010andfurtherimprovedbyHoustonetal.,2018tomodeltheJovianaurora.Wenowsimulateawiderrangeofincidentoxygenionenergies(10keV/u-25MeV/u)andupdatethecollisioncross-sectionstomodeltheionizationoftheatmosphericneutrals.Thepolarcaplocationoftheemissionindicatetheassociatedfield-alignedcurrentsmustoriginatenearthemagnetopauseorperhapsthedistanttail.Secondaryelectronsproducedintheupperatmospherebyionprecipitationcouldbeacceleratedupwardtorelativisticenergiesduetothesamefield-alignedpotentialsresponsibleforthedownwardionacceleration.Tofurtherexplorethis,wesimulatetheeffectofthesecondaryelectronsgeneratedfromtheheavyionprecipitation.Weuseatwo-streamtransportmodelthatcomputesthesecondaryelectronfluxes,theirescapefromtheatmosphere,andcharacterizationoftheH2Lyman-Wernerbandemission,includingapredictedobservablespectrumwiththeassociatedcolorratio.Moreover,weperformsomepreliminarycalculationsoftheeffectofprotonprecipitationintothepolaratmosphereanditscontributionstotheauroraldynamics.
46
![Page 47: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/47.jpg)
CosmicDustAnalyzeronboardCassiniCollectsMaterialfromSaturn’sMainRingsHsu,H.-W.,LASP,UniversityofColoradoBoulderSchmidt,J.,Kempf,S.,Postberg,F.,Moragas-Klostermeyer,G.,Seiss,M.,Hoffmann,H.,Burton,M.E.,Ye,S.Y.,Kurth,W.S.,Horanyi,M.,Khawaja,N.,Spahn,F.,Schirdewahn,D.,O'Donoghue,J.,Moore,L.,Cuzzi,J.,Jones,G.,Srama,R.
TheregioninsideofSaturn'sDringsampledduringtheCassini'sGrandFinaleMissionispredominantlypopulatedbygrains10snminradii,whosedynamicsisconsistentwithimpactejectafromSaturn'smainrings.Electromagneticforcesleadtoafasttransportoftiny,chargedejectagrains(<hours),whichcomprisesaringmasslosspathway(100-1,000kg/s).About20%ofthemfallintoSaturn,mainlyintheequatorialregionandthesouthernhemisphere,andleadtotheobservedH3
+ionosphericsignature,i.e.,the"RingRain"effect.Twograincompositiontypeswereidentifiedfrom~25%ofrecordedmassspectra-watericeandsilicates,withaicefractiondecreasingfromaround80-100%neartheringplanetowardshighlatitudes.Wefindnoindicationofgrainswithpureorganicsoriron-oxidecompositions.Juno-UVSobservationoftheIofootprintHue,V.,SouthwestResearchInstituteGreathouse,T.K.,BonfondB.,Gladstone,G.R.,Davis,M.W.,Gérard,J.-C.,Grodent,D.C.,Kammer,J.,Roth,L.,Saur,J.,Versteeg,M.,Bolton,S.J.,Connerney,J.E.P,Levin,S.
TheperijoveobservationsperformedbyJuno-UVSnominallyrangefrom-5hoursupto+5hoursaboutperijove,duringwhichJuno’sdistancetoJupiterrangesfrom7RJdownto1.05RJ.TheIofootprintsareacharacterizationofthecomplexelectrodynamicinteractiongeneratedatIoandmodulatedbytheinnermagnetosphereofJupiter.PreviousobservationswiththeHubbleSpaceTelescopeallowedthecharacterizationofthefootprintsasafunctionofIo’scentrifugallatitude,despiteobservationalbiasthatEarth-basedobserversaresubjectto.Juno’suniquevantagepointintheJoviansystemremovesthesebiasesallowingUVSaccesstothefullrangeofcentrifugallatitudesandallpossiblelocaltimegeometries.WewillpresentourinvestigationofthelocaltimevariabilityinIo’sfootprintemittedpowerandcolorratio,includingobservationsofthefootprintswhileIowasineclipse.
47
![Page 48: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/48.jpg)
Field-alignedcurrentsfromtheF-ringorbitsofCassiniHunt,G.J,ImperialCollegeLondonProvan,G.,Bunce,E.J.,Cowley,S.W.H.,Dougherty,M.K.,Southwood,D.J.
Weinvestigatetheazimuthalmagneticfieldsignaturesassociatedwithhigh-latitudefield-alignedcurrentsobservedduringCassini’sF-ringorbits(October2016–April2017).Therearedistinctdifferencesbetweenthe2016-2017periodandapreviousopportunitytostudythefield-alignedcurrentprofilesin2008,mostnotablyintheregionspolarwardandequatorwardofthefield-alignedcurrents.Wediscussthesedifferencesintermsoftheseasonalchangebetweendatasetsandlocaltime(LT)differences.TheF-ringfield-alignedcurrentstypicallydohavethesimilarfourcurrentsheetstructurelikethosein2008.Onceagain,wecanshowthatthefield-alignedcurrentsinahemisphereareacentralpartofthathemisphere’s“planetaryperiodoscillation”(PPO)systems.WeseparatethePPO-independentandPPO-relatedcurrentsinbothhemispheresusingtheiroppositesymmetry.TheaveragePPO-independentcurrentspeakat~1.5MArad-1justequatorwardoftheopenclosedfieldlineboundary,similartothe2008observations.However,thePPO-relatedcurrentsinbothhemispheresarereducedby~50%to~0.4MArad-1.ThismaybeevidenceofreducedPPOamplitudes,similartothepreviouslyobservedweakerequatorialoscillationsatsimilardaysideLTs.WecannotdetectthePPOcurrentsystems’interhemisphericcomponent,likelyaresultoftheweakerPPO-relatedcurrentsandtheirclosurewithinthemagnetosphere.Wealsodonotdetectpreviouslyproposedlowerlatitudediscretefield-alignedcurrentsthatwouldacttoshieldthePPOsfrominvariantlatitudesinsideEnceladusorbit.However,wewillshowevidenceofthedistributedPPOfield-alignedcurrentsuptotheedgeoftheF-ring.PlasmasheetpropertiesobservedbyJunoatJupiterHuscher,E.,UniversityofColoradoBagenal,F.,Wilson,R.J.,Valek,P.,Allegrini,F.
UsingJuno’sfirstsciencepassesthroughthejoviansystem,wecombinemeasurementsfromthefieldsandparticlesinstrumentsontheJunospacecrafttomakeapreliminarymapofthepropertiesintheplasmadisk.Juno’sorbitisparticularlyusefulforexploringthevariationinpropertieswithlatitudeaswellasradialdistance(beyond~10RJ).Wecomparebasicplasmaproperties(flow,density,temperature,composition,magneticfieldstrength)aswellasderivedquantities(pressure,plasmabeta,Alfvenspeed)withthosefrompreviousobservations(specificallyVoyagerandGalileo)andestimatetheflowofmassandenergythroughthesystem.
48
![Page 49: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/49.jpg)
SignaturesofEuropa’satmosphereinGalileoEPDdataduringtheE12flybyHuybrighs,H.L.F.,MaxPlanckInstituteforSolarSystemResearchRoussos,E.,Krupp,N.,Fraenz,M.,Futaana,Y.,Barabash,S.,Glassmeier,K.-H.
Jupiter’smoonEuropaisthoughttobesurroundedbyatenuousatmosphereofneutralparticles.ObservationsofthisatmospherearelimitedtoremotesensingobservationsbytheHubblespacetelescope(e.g.Rothetal.,2014orSparksetal.,2016).However,currentlylackingarein-situdetectionsoftheatmosphere.Inthiswork,inordertoassesstheexistenceofsuchatenuousatmosphere,weinvestigateaseriesofenergeticiondepletionfeaturesfoundindatacollectedbyGalileo’sEnergeticParticleDetector(EPD)duringtheE12flyby.
EnergeticiondepletionscanbecausedbytheprecipitationoftheseparticlesontoEuropa’ssurface.Additionally,suchlossescanoccurwhentheenergeticionschargeexchangewithneutralparticlessurroundingEuropa.Therefore,aMonteCarloparticletracingcodehasbeendevelopedtosimulatethedepletionfeaturesunderdifferentscenariosincludingthosewithandwithoutanatmosphere.Theatmosphericmodelassumesanexponentiallydecayingdensityandisfullydeterminedbyasurfacedensityandscaleheight.
ThesimulationwithouttheatmospherecouldnotreproducethedepletionfeaturesintheEPDdata.ThisdiscrepancysuggeststhattheobserveddepletionfeaturescannotbesolelyattributedtointeractionoftheparticleswithEuropa’ssurface,andthatEuropathereforepossesanatmosphere.Severalsimulationrunswithanatmosphereforcertainrangesofsurfacedensityandscaleheighthavebeenconducted.BycomparingthesimulationresultswiththeEPDdeletiondata,wesuggestconstraintsonthesurfacedensityandscaleheightofEuropa'satmosphere.
CubeSatprojectforJupiter'sradioscienceImai,Kazumasa,NationalInstituteofTechnology,KochiCollegeNobutoHirakoso,KentarouKitamura,TakuTakada,KOSEN-Space-RenkeiGroup,CharlesA.Higgins,JamesR.Thieman,NASARadioJOVETeam
SincethediscoveryofJupiter'sdecametricradioemissionsin1955,importantdetailsofitsradiationmechanismhavenotyetbeenelucidated.InordertoinvestigatethebeamingstructureofJupiter'sradioemissiontoclarifyaspectsoftheemissionmechanism,weplantolauncha2U-sizeCubeSatforobservationofJupiter'sradiowavesandobservesimultaneouslyinouterspaceandontheground.Thepurposeofthisprojectistomeasuretheemissiondelaytimebyusingacorrelationanalysismethod.ThedelaytimecanbemeasuredbythecorrelationanalysisofwaveformdataobtainedbysimultaneousobservationsofJupiter'sradioSburstsbetweenthissatelliteandtheground.IfthebeamofJupiter'sradioSburstsismovingtogetherwiththerotationofJupiter,wecancalculateatimedifferenceofabout70millisecondsatthebaselinelengthof8000km.UsingtheproposedsimultaneousobservationsitispossibletotestwhethertheJovianSburstsareemittedlikea'beacon',rotatingwithJupiter'smagneticfieldandsweepingbytheEarth,orlikea'flashlight',aninstantaneousemissionwitha0millisecondtimedelay.ThisresultisveryimportantinformationtodeterminethenatureoftheJupiter'sradioemissionmechanism.ThisCubeSatisbeingconsideredtobelaunchedfromtheInternationalSpaceStation(ISS).Thedurationofthepossibleobservationisestimatedtobemorethan50days.Theworldwideground-basedobservationswillbesupportedbytheNASARadioJOVEproject,aneducationandoutreachprogramforplanetaryradioastronomy.ThisprojectissupportedbytheCoordinationFundsforPromotingAeroSpaceUtilizationtheMinistryofEducation,Culture,Sports,ScienceandTechnology(MEXT),JAPAN.
49
![Page 50: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/50.jpg)
FrequencydependenceonthebeamingangleofJupiter'sdecametricradioemissionsImai,Kazumasa,NationalInstituteofTechnology,KochiCollegeCharlesA.Higgins,MasafumiImai,TracyClarke
ThebeamingangleofJupiter'sdecametricradioemissionsisveryimportanttoelucidatetheemissionmechanismofJupiter'sdecametricradioemissions.Thisbeaminganglecanbeestimatedbythemodulationlanemethod[Imaietal.,2017].ThemodulationlanemethodisbasedonthemeasurementsoftheslopeofmodulationlanesonthedynamicspectrumofJupiter'sdecametricradioemissions.Weusuallymeasuretheslopewitha1MHzbandwidthanddeterminethemostprobablevalueoftheleadangletofitthevalueoftheslope.Thelongitudinallocationofthemagneticfieldlineoftheradioemittingsourcescanbecalculatedbytheleadangle.Oncethelocationofthesourceisfound,wedeterminethebeamingangle(so-calledconehalf-angle)astheanglebetweenthedirectiontangenttothemagneticfieldlineatthesourceandthedirectiontotheEarthasseenfromthesource.
TheLongWavelengthArraystation1(LWA1)isalow-frequencyradiotelescopedesignedtoproducehigh-sensitivity,high-resolutionspectrainthefrequencyrangeof10-88MHz.ThesensitivityoftheLWA1,combinedwiththelowradiofrequencyinterferenceenvironment,allowsustoobservethewidebandmodulationlanesofJupiter'sdecametricradioemissions[Clarkeetal.,2014].WehaveanalyzedthedataincludingthewidebandIo-BmodulationlanesobservedbyLWA1.Wefoundauniqueeventshowingcurvedmodulationlanesovera22MHzfrequencybandwidthfrom12MHzto34MHz.Byusingourmodulationlanemethodwecalculatedbeaminganglesof57degreesfor12MHzand63degreesfor34MHz.Thedifferenceofthebeaminganglesis6degreesovera22MHzfrequencyrange.Thismeansthevalueofbeamingangleisgraduallyincreasingtowardthehigheremittingfrequency.WewilldiscussthisfrequencydependenceonthebeamingangleofJupiter'sdecametricradioemissionsbasedonthearchivedLWA1data.StereoscopicobservationsofJoviandecametricradioarcsassociatedwithultravioletaurorasImai,M.,UniversityofIowaKurth,W.S.,Bonfond,B.,Grodent,D.,Hospodarsky,G.B.,Bolton,S.J.,Connerney,J.E.P.,Levin,S.M.,Lecacheux,A.,Lamy,L.,Zarka,P.,Clarke,T.E.,Higgins,C.A.,Cecconi,B.
AurorasinJupiter’spolarregionsshowcomplexactivityoverabroadrangeofelectromagneticwavelengths.Oneoftheauroralradiocomponents,decametricradiation(DAM),dominatesthefrequencyrangefromafewto40MHzandisproducedatafrequencyveryclosetothelocalelectroncyclotronfrequency.SinceJunofirstbegandetectingsporadicDAMarcsonMay5,2016,duringtheapproachtoJupiter,theDAMradioarcshavebeenmonitoredinafrequencyrangeof3.5to40.5MHzbyseveralobservatories.TheseincludeJunoatJupiter,CassiniatSaturn,STEREOAat1AU,WINDatEarth,andEarth-basedradioobservatories(LongWavelengthArrayStationOne(LWA1)inNewMexico,USA,andNançayDecameterArray(NDA)inFrance).WehavecarriedoutavisualsurveyofthespectraldatatoidentifyconcurrentDAMradioarcs,fromMay5,2016,throughSeptember,2017(Cassini’send-of-mission).Wefoundsixeventsforwhichtwoormoreobserversclearlycapturedthesamegroupofarcs.InoneoftheeventsonDecember3,2016,JunofirstcapturedagroupoftheDAMarcsaround4:00UTandtwointensearcswerelaterrecordedinNDAspectrogramsat6:30and7:45UT.Onthesamedayfrom13:44to14:24UT,theHubbleSpaceTelescope(HST)observedabrightauroralarcatultravioletwavelengthswithanemittedpowerof20to25GW,suggestingapossiblelinktotheconcurrentlyobservedDAMarcs.Inthispaper,weshowresultsfromthestereoscopicDAMradioobservationsandcomparewiththeultravioletaurorascapturedbyHST.
50
![Page 51: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/51.jpg)
Assessingquasi-periodicitiesinJovianX-rayemissions:techniquesandheritagesurveyJackman,C.M.,UniversityofSouthamptonKnigge,C.,Altamirano,D.,Gladstone,R.,Dunn,W.,Elsner,R.,Kraft,R.,Branduardi-Raymont,G.,Ford,P.
WearecurrentlyinanexcitingeraforjoviansciencewiththeJunospacecraftinorbitaroundJupiterandseveralEarth-basedandspace-basedobservatoriesstudyingJupiterinmultiplewavelengths.Jupiter’sauroralX-raysarerathermysterious,withanunknowndriver,andseveralpreviousreportsofindividualcasesofquasi-periodicemission.InthisworkwerevisitheritageX-raydatasetsfromthe1990sto2015andapplysignificancetestingofemergingquasi-periodicities,seekingtounderstandtherobustnessandregularityofpreviouslyreportedquasi-periodicemissions.OuranalysisincorporatestheuseoftheRayleightestasanalternativetoLomb-Scargleanalysis,whereRayleighisparticularlysuitedtoatime-taggeddatasetofsparsecountssuchasiscommonforjovianX-raydata.Furthermore,theanalysistechniquesthatwepresent(includingRayleighandMonte-Carlosimulation)canbeappliedtoanytime-taggeddataset.Wefindfiveinstancesofquasi-periodswithsingletrialsignificancesabovethe99thpercentilefromJupiter’snorthernauroralregion,withperiodsrangingfrom~8.1to47.6minutes,andthreeinstancesfromthesouth,withperiodsof~11,24and42minutes.Theselectionofarestrictivehotspotsourceregionseemstobecriticalfordetectingquasi-periodicemission.PeriodsvaryfromoneJupiterrotationtothenextinonelongobservation,andthenorthandsouthareshowntopulseindependentlyinanotherconjugateobservation.TheseresultshaveimportantimplicationsforunderstandingthedriverofjovianX-rayemission.PlasmaobservationsatSaturn’shigh-latitudemagnetosphereandcuspJasinski,J.M.,NASA-JetPropulsionLaboratoryMurphy,N.
Thehigh-latitudepolarmagnetosphereatSaturnislocatedonopenfieldlineswhicharelargelydevoidofplasmadenseenoughtobemeasuredbytheCassiniPlasmaSpectrometer.However,embeddedwithinthislargely“empty”polarmagnetosphereareunexplainedobservationsofsporadicburstsoftenousplasma,whichwepresenthere.Additionally,weshowrecentanalysisplasmacomposition,structureandvariabilityinSaturn’scusps.
51
![Page 52: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/52.jpg)
SurveyofElectronmeasurementsatSaturn'sMagnetosphereusingCAPS-ELSJasinski,J.M.,NASA-JetPropulsionLaboratoryMurphy,N.,Coates,A.J.
UsingallthedatafromCassini'sElectronSpectrometer(ELS)wecomposeasurveyofSaturn'smagnetosphere.Wefocusonmeasureingtheregionswherethereisnoplasmaobserved.Thisletsusidentifywheretheopen-closedfieldlineboundaryisinthehigh-latitudesandwherethereconnectionx-lineisinthenightsidetailatlowlatitudes.Fromthisweestimateaveragemagneticfluxesintheopenpolarcaps.Wealsofindadawn-duskasymmetryintheouterequatorialmagnetosphere.CoupledFluid-kineticGlobalSimulationsofSaturn'sMagnetopauseDynamicsJia,X.,UniversityofMichiganChen,Yuxi;Toth,Gabor;Slavin,James.A.;Kivelson,MargaretG.;Gombosi,TamasI.
Thegiantplanets,JupiterandSaturn,arerapidrotatorswithstronginternalsourcesofplasmaarisingfromtheirmoons.Theroleofsolarwind-driventransportattheseplanetshasbeenatopicofintenseinterest.BothmagneticreconnectionandKelvin-Helmholtz(K-H)instabilityhavebeensuggestedtoplayanimportantroleincouplingthesolarwindwiththemagnetosphere.TodeterminetheimpactofreconnectionandK-Hinstabilityonthegiantplanetmagnetospheres,wehaveadaptedacoupledfluid-kineticglobalmodeltothegiantplanetsbasedontheMHDwithembeddedparticle-in-cell(MHD-EPIC)codeoriginallydevelopedforEarthandGanymede.TheMHDcode(BATSRUS)isemployedoverthefullsimulationdomain,whilethefullykineticcode(iPIC3D)coversregionswherekineticphysicsisimportant.Thetwo-waycoupledMHD-EPICprovidesauniquecapabilityofsimulatingreconnectionatkineticscaleswhilesimultaneouslycapturinglarge-scaleeffectsofreconnectiononaglobalmagnetosphere.Inthispresentation,wereportonfirstresultsfromourMHD-EPICsimulationsofthesolarwindinteractionwithSaturn'smagnetopause.OurSaturnMHD-EPICmodelhasbeenrunwithvariousIMFconditions(northward,southward,spiralconfigurations)todeterminethemainprocessthroughwhichthesolarwindiscoupledtothemagnetosphere.WehavealsoperformedpurelyMHDsimulationsforthesameupstreamandinternalconditionsasusedinMHD-EPICtoidentifyhowtheeffectsofboundaryprocessesdifferinthetwomodels.ThesecomparisonsallowustodeterminewhenandwherereconnectionorK-Hlikeinstabilitiesoccurundertheexternalandinternalconditionspertinenttothegiantplanetmagnetospheres.Asaquantitativemeasureoftheglobalcouplingefficiency,weanalyzetherateatwhichopenmagneticfluxisbeingaddedtothepolarcapandhowitvarieswiththeIMForientation,andcomparetheresultsbetweenMHD-EPICandMHDsimulations.
52
![Page 53: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/53.jpg)
EvidenceofaPlumeonEuropafromGalileoMagneticFieldandPlasmaWaveSignaturesJia,X.,UniversityofMichiganKivelson,MargaretG.;Khurana,KrishanK.;Kurth,WilliamS.
TheicysurfaceofJupiter’smoon,Europa,isthoughttolieontopofaglobalocean.SignaturesinsomeHubbleSpaceTelescopeimageshavebeenassociatedwithputativewaterplumesrisingaboveEuropa’ssurface.PlumesthusfaridentifiedfromHubbleimagesaresimilarinspatialscale,appearingtorise~200kmabovethediskofEuropa’ssolidbody.TheonesneartheequatorarelocatedonEuropa’strailinghemispheresouthoftheequatorinaregionofcomparativelyhighsurfacetemperature.However,alltelescopicdetectionsreportedweremadeatthelimitofsensitivityofthedata,therebycallingforasearchforplumesignaturesinin-situmeasurements.Herewereportin-situevidenceofaplumeonEuropafromthemagneticfieldandplasmawaveobservationsacquiredonGalileo’sclosestencounter(E12)withthemoon.Onthisflybythatdroppedbelow400kmaltitude,themagnetometerrecordeda~1000kmscalefieldrotationandadecreaseofover200nTinfieldmagnitudeandthePlasmaWaveSpectrometerregisteredintenselocalizedwaveemissionsindicativeofabriefbutsubstantialincreaseinplasmadensity.WehavemodeledtheE12flybyusinga3Dmulti-fluidmagnetohydrodynamic(MHD)modelthatincorporatesaplumewithpropertiesconsistentwiththoseinferredfromtheHubbleobservations.Weshowthatthelocation,duration,andvariationofthemagneticfieldandplasmawavesignaturesareentirelyconsistentwiththeinteractionofJupiter’scorotatingplasmawithEuropaifaplumewithcharacteristicsinferredfromHubbleimageswaseruptingfromtheregionofEuropa’sthermalanomalies.OurresultsprovidestrongindependentevidenceofthepresenceofplumesatEuropa.Juno-UVSMeasurementsofHigh-EnergyRadiationatJupiterKammer,J.A.,SouthwestResearchInstituteGladstone,G.R.,Greathouse,T.K.,Versteeg,M.H.,Hue,V.,Davis,M.W.,Becker,H.N.,Bolton,S.J.,Connerney,J.E.P.,Levin,S.M.
Juno-UVSisanultravioletspectrographthatprimarilyobservesJupiter’sauroralemissions,buttheinstrumentisalsosensitivetopenetratinghigh-energyradiation(generally>10MeVelectrons),whicheffectivelyactsaswhitenoiseduringUVobservations.Instudyingthisradiationbackgroundnoise,wefindthatthelevelofmaximumbackgroundradiationobservedbyJuno-UVSvariesonatimescaleofhours,and-basedontheoutputofmagneticfieldmodels-theinstrumentcountrateduetohighradiationreachesitsmaximumincertainregionsaroundJupiterdependingonrho,thespacecraftdistancefromthemagneticdipoleaxis,andz,thespacecraftdistanceabovethemagneticequator.WeusethisempiricalrelationshiptopredictthelevelsofradiationseenbyJuno-UVSforfutureperijoves.Wealsofindthatmeasuredlevelsofradiationvaryonshorter(~30second)timescalesduetothespinningofthespacecraft,andhavedevelopedmodelstoexplainthisvariationasafunctionofspinphase.WepresentcomparisonsoftheJuno-UVSdatafromeachoftheperijovepassessofar,anddiscusswhatfutureperijovesmightrevealaboutthenatureandextentofhigh-energyradiationaroundJupiter.
53
![Page 54: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/54.jpg)
CassiniMission-wideAnalysisofHotIonsDetectedbytheINCAandCHEMSInstrumentsintheMagnetosphereofSaturnKane,M.,HRIMitchell,D.G.,Hill,M.E.,Carbary,J.F.,Krimigis,S.M.
AnextensiveanalysisofCassiniINCAandCHEMSmeasurementsof5-149keVionsacquiredduringselectedperiodsofnearlyallmissionorbitshasbeencompleted.Inadditiontoselectedperiodswithinnearlyallequatorialorbits,dataacquiredwhenthespacecraftwaswithin~20degreeslatitude,whereconditionspermitted,formostnon-equatorialorbitswasalsoanalyzed.Thecoveragespansalllocaltimesandrangesfrom~6Rstothemagnetopauseinthedaysideandto~70Rsonthenightside.Usingaconvectedkappadistributionasthemodelforthehotionpopulations,thedensity,temperature,3componentvelocity,andspectralindexwerecalculatedfromabestfittotheCHEMSandINCAinstrumentdata.ForINCA,oxygenionswereanalyzedseparately.SpinandstarespacecraftmodeswereanalyzedforbothINCAandCHEMS.ThecomputedplasmafractionalcorotationspeeddecreasessharplywithincreasingdistancefromSaturn.Theoxygenionprofilefollowsthehydrogeniontrend.Thepolarconvectionspeedisthesmallestofthe3velocitycomponents,andiscenteredaboutzero,buttheradialspeedhasasignificantoutwardradialcomponentandisenhancedinthepre-dawnsector.ThehydrogenandoxygentemperaturesincreasewithdecreasingdistancetoSaturn.Thecalculatedpatternofconvectionisconsistentwithanempiricalmodelofplasmaconvectionthatincludesoutwardradialtransportandescapeofplasmainadawnsideboundarylayerofplasmaentrainedbythedawnmagnetosheathflow.However,CHEMSanalysisoftheinnerregionsinthenightsideindicateaninwardcomponenttothevelocity,possiblyanindicationoftheexistenceofhotioninjections.Whenthemodelconvectionpatternisscaledtothesub-solarmagnetopausedistanceandtothesizesofJupiterandSaturn,thepatternagreeswiththatderivedfromanalysisofhotionsdetectedbytheLECPdetectoronVoyagerandtheEPDinstrumentonGalileo.
54
![Page 55: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/55.jpg)
HighFrequencypartinRadio&PlasmaWaveInvestigation(RPWI)aboardJUICE:TowardtheinvestigationofJupiterandIcyMoonsSystemKasaba,Y.,TohokuUniversityCecconi,B.,Misawa,H.,Tsuchiya,F.,Kumamoto,A.,Kimura,T.,Kita,H.,Nakamura,Y.,Miyoshi,Y.,Kasahara,Y.,Kojima,H.,Jarzynka,S.,Palma,P.,Tokarz,M.,Wiśniewski,Ł.,Puccio,W.,Bergman,J.,Wahlund,J.-E.
In2018wedeveloptheQM/PFM/FMofRadio&PlasmaWaveInvestigation(RPWI)aboardESAJUICE.RPWIprovidesanelaboratesuiteforelectromagneticfieldsandplasmaenvironmentaroundJupiterandicymoons,with4Langmuirprobes(LP-PWI;3-axisE-field-1.6MHz,andcoldplasmas),asearchcoilmagnetometer(SCM;3-axisB-field-20kHz),andatri-dipoleantennasystem(RWI;3-axisE-field0.08-45MHz,2.5-mtip-to-tiplength).
RWIwithHighFrequencyReceiver(HF)providethehighestsensitivityreachingthegalacticbackgroundforthehighly-resolvedJovianradioemissionsfrommagnetosphere(auroraetc.),atmosphere(lightning),andicymoons.Itsdirectionandpolarizationcapabilitiesenableustoidentifythesourcelocationsandcharacteristics.TheirdevelopmentsareunderthecollaborationofJapan,France,PolandandSweden,basedontheH/WandS/WdesignsofKaguya-LRS/BepiColombo-PWI/Arase-PWEandCassini-RPWS.Inthispaper,weintroducekeyactionstakeninrecentyearstoachievethebestperformancesandquietenvironmentwithenoughtoleranceforwidetemperaturerangearoundVenus-Jupiterandharshplasmaenvironment(charging&intenseradiation).
Asabyproduct,wetrythepassivesubsurfaceradar(PSSR)tosoundtheicycrustsofGalileansatellites,bythereflectionsofJovianHOM/DAM.Forcontinuousandcoherentwaves,reflectorinformationisdeterminedbyspectrumpatternscausedbytheinterferenceamongthedirectwave,reflectedonefromsurface,andscatteredonebysubsurface.Forburstwaves,thereflectioncomponentisdeterminedbycross-correlationofthewaveformsfor~msecslength.Althoughitisnoteasytoreachthetopofsubsurfaceoceanbystrongattenuationoftheiceclosetoitsmeltingtemperature(>50dB/km),wearelookingforwardtoseerealdataandsupportthesubsurfacestudiesexecutedbyRIME(activeradarsounder)andmanypayloadteamswhohavemuchinteresttothistopic.Software-typeWave-ParticleInteractionAnalyzer(S-WPIA)byRPWIforJUICEKatoh,Y.,TohokuUniversity,JapanH.Kojima,K.Asamura,Y.Kasaba,F.Tsuchiya,Y.Kasahara,T.Imachi,H.Misawa,A.Kumamoto,S.Yagitani,K.Ishisaka,T.Kimura,M.Hikishima,Y.Miyoshi,M.Shoji,M.Kitahara,O.Santolik,J.Soucek,J.Bergman,W.Puccio,R.Gill,M.Wieser,W.Schmidt,S.Barabash,andJ.-E.Wahlund
Software-typeWave-ParticleInteractionAnalyzer(S-WPIA)willberealizedasasoftwarefunctionofrunningontheDPUofRPWI(RadioandPlasmaWavesInvestigation)fortheESAJUICEmission.S-WPIAconductsonboardcomputationsofphysicalquantitiesindicatingtheenergyexchangebetweenplasmawavesandenergeticions.Onboardinter-instrumentscommunicationsarenecessarytorealizeS-WPIA,whichwillbeimplementedbyeffortsofRPWI,PEP(ParticleEnvironmentPackage)andJ-MAG(JUICEMagnetometer).TheprimetargetofS-WPIAinJUICEisioncyclotronwavesandrelatedwave-particleinteractionsoccurringintheregionclosetoGanymedeandotherJoviansatellites.Low-Frequencyreceiver(LF)andLangmuirProbes(LP)datawillbeusedforelectromagneticwaveformofioncyclotronwavesinthefrequencyrangeofafewHz.Fortheparticledata,S-WPIAusesparticlecountsdetectedbyJovianplasmaDynamicsandComposition(JDC)ofPEPintheenergyrangefrom1eV/qto25keV/q.ByprovidingthedirectevidenceofionenergizationprocessesbyplasmawavesaroundJoviansatellites,S-WPIAincreasesthescientificoutputofJUICEwhilekeepingitsimpactonthetelemetrydatasizetoaminimum.
55
![Page 56: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/56.jpg)
DiscoveryofAtmospheric-Wind-DrivenElectricCurrentsinSaturn’sMagnetosphereintheGapbetweenSaturnanditsRingsKhurana,K.K.,Dept.ofEarth,PlanetaryandSpaceSciences,UniversityofCalifornia,LosAngeles,CA,90095DoughertyM.K.,ProvanG.,HuntG.J.,KivelsonM.G.,CowleyS.W.H.,SouthwoodD.JandRussellC.T.
AsCassinirepeatedlytraversedthegapbetweenSaturn’satmosphereanditsDringduringtheproximalorbits,theazimuthalcomponentofthemagneticfieldshowedaconsistentpositiveperturbationwithastrengthof15-25nTneartheclosestapproach.TheclosestapproacheswereneartheequatorialplaneofSaturnandweredistributednarrowlyaroundthelocalnoonandbroughtthespacecrafttowithin2550kmofSaturn’scloudtops.Modelingofthefieldintermsofsphericalharmonicsshowsthattheperturbationisnotofinternaloriginbutisproducedbyexternalcurrentsthatcouplethelow-latitudenorthernionospheretothelow-latitudesouthernionosphere.Theazimuthalperturbationsdiminishathigherlatitudesonfieldlinesthatconnecttothering.TheconsistentpositiveazimuthalperturbationobservedbyCassinineartheequatorialplanesuggeststhatthespacecraftpassedinbetweentwoshellsofoppositelydirectedcurrentslinkedintheionosphere.TheoutershellwascrossedbyCassinitwiceandiscomposedoffield-alignedcurrentsthatareflowinginthesouthwarddirection.TheinnershellwasnotcrossedbyCassini.Weshowthatthestrengthofthiscurrentsystemis~1MA/radian,i.e.comparableinstrengthtotheplanetary-period-oscillationrelatedcurrentsystemsobservedintheauroralzone.WeshowthattheLorentzforceintheionosphereextractsmomentumfromthefastermovingequatorialzonalbeltanddeliversittothenorthernionosphere.Wefurthershowthatelectriccurrentsaregeneratedwhenthetwoendsofafieldlinesareembeddedinzonalflowswithdifferingwindspeedsinthelow-latitudethermosphere.Thewind-generatedcurrentsdissipate2×10^11Wofthermalpower,similartotheinputfromthesolarEUVfluxinthisregion.IonPropertiesofJupiter'sPlasmaSheet:JunoJADE-IObservationsKim,T.K.,DepartmentofPhysicsandAstronomy,UniversityofTexasatSanAntonio,SanAntonio,TX,USAValek,P.W.,McComas,D.J.,Allegrini,F.,Bagenal,F.,Clark,G.,Connerney,J.E.P.,Ebert,R.W.,Kollman,P.,Livadiotis,G.,Mauk,B.H.,Thomsen,M.F.,Wilson,R.J.,Levin,S.,Bolton,S.
WepresentobservationsofJovianplasmasheetionsasmeasuredbytheJovianAuroralDistributionsExperimentIonsensor(JADE-I)ontheJunospacecraft.JADE-Imeasuresanion’senergy-per-charge(E/Q)from0.01-46.2keV/qandmass-per-charge(M/Q)from1-64amu/q.ThisextendedE/QandM/QinformationpermitsdetailedobservationsofJupiter’splasmasheet.WepresentbulkionplasmapropertiesforH+,O+,O2
+,O3+,Na+,S+,S2+,andS3+obtainedfromaforwardmodel.Theforward
modelutilizessimulatedinstrumentresponsefunctions(fullraytracingsimulationwithcarbon-foil-effects)toreproducethe2-dimensionalE/Qandtime-of-flightmeasurementsoftheplasmasheetionsbasedonaconvectedkappadistribution.Maxwell-Boltzmanndistributionsaretypicallyusedtodescribesystemsinthermalequilibrium.Butspaceplasmasaremostlyconsideredascollisionlessandarenotalwaysinthermalequilibrium.Oftentimes,suchsystemshavedistributionsextendingtohigherenergies(highenergytail)andcanbebetterdescribedwithkappadistributions.Inourforwardmodelweassumeallionshaveacommonflowspeed(alongtheco-rotationdirection)andisotropicdistributionswithdifferenttemperatureandkappaindexforprotonandheavyions(i.e.,M/Q>5).Wefindthattheplasmatemperaturesanddensitiesarehigherthanpreviouslyreported.
56
![Page 57: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/57.jpg)
ResponseofJupiter'sAuroratoPlasmaMassLoadingRateMonitoredbytheHisakiSatelliteDuringVolcanicEruptionsatIoKimura,T.,TohokuUniversityHiraki,Y.,Tao,C.,Tsuchiya,F.,Delamere,P.,Yoshioka,K.,Murakami,G.,Yamazaki,A.,Kita,H.,Badman,S.V.,Fukazawa,K.,Yoshikawa,I.,Fujimoto,M.
Theproductionandtransportofplasmamassareessentialprocessesinthedynamicsofplanetarymagnetospheres.AtJupiter,itishypothesizedthatIo’svolcanicplasmacarriedoutoftheplasmatorusistransportedradiallyoutwardintherotatingmagnetosphereandisrecurrentlyejectedasplasmoidviatailreconnection.Theplasmoidejectionislikelyassociatedwithparticleenergization,radialplasmaflow,andtransientauroralemissions.However,ithasnotbeendemonstratedthatplasmoidejectionissensitivetomassloadingbecauseofthelackofsimultaneousobservationsofbothprocesses.WereporttheresponseofplasmoidejectiontomassloadingduringlargevolcaniceruptionsatIoin2015.ResponseofthetransientauroratothemassloadingratewasinvestigatedbasedonacombinationofHisakisatellitemonitoringandanewly-developedanalyticmodel.Wefoundthetransientaurorafrequentlyrecurredata2–6-dayperiodinresponsetoamassloadingincreasefrom0.3to0.5ton/s.Ingeneraltherecurrenceofthetransientaurorawasnotsignificantlycorrelatedwiththesolarwindalthoughtherewasanexceptionaleventwithamaximumemissionpowerof~10TWafterthesolarwindshockarrival.Therecurrenceofplasmoidejectionrequiresthepreconditionthatamountcomparabletothetotalmassofmagnetosphere,~1.5Mton,isaccumulatedinthemagnetosphere.Aplasmoidmassofmorethan0.1Mtonisnecessaryincasethattheplasmoidejectionistheonlyprocessformassrelease.AnalysingCassiniUVIS&INCAimageryduringinjectioneventsatSaturn:aninverseproblemKinrade,J.,LancasterUniversityBadman,S.V.,Gray,R.L.,Mitchell,D.G.,Paranicas,C.,Arridge,C.S.,Ray,L.C.,A.Bader,Pryor,W.R.
Large-scaleinjectioneventsfromSaturn’smagnetotailproducerotatingsignaturesinboththeplanet’sauroralemissionandmagnetospherichotplasmapopulation.Previouslythesesignatureshavebeenobservedtotrackthroughsimilarlocaltimes,whichsuggestsacausallinkbetweenanauroralsourceregioninthemagnetosphereandanultimatesinkintheionosphere,likelyconnectedviafieldalignedcurrents.Thephysicsdrivingthiscurrentsystemandrotatingauroralemissionarenotfullyunderstood.Dopressuregradientsassociatedwithinjectionflowchannelsdrivecurrentsthatproducetheauroralsignature?Doesgradient-curvaturedriftrestrictauroralcurrentstotheedgesofinjectionregionsaschargeseparationisolatestheenergeticionsandelectrons?Doestheionosphereimpedemotionoftheinjectedplasma?
TheCassiniUltravioletImagingSpectrograph(UVIS)capturesSaturn’smostintenseUVauroralemissions,whicharetheoptical,ionosphericfingerprintofhotplasmainthemagnetosphere.ImagingofEnergeticNeutralAtoms(ENAs)usingCassini’sIon-NeutralCamera(INCA)providesaglobalviewofthemagnetosphere’shotplasmapopulation.Herewediscusshowthesetwoimagesetsmaybecomparedintheframeofaninverseproblem,torevealthedynamicsoftheauroralsourceregionanddrivingcurrentsduringlarge-scaleinjectionevents.Toresolveradialandazimuthalmotions,wetranslatetheauroralandENAimagerytoacommonmagnetosphericgrid,andautomaticallytrackauroralenhancementsusingadynamicintensitythreshold.WetesthowtheFUVintensityandspectraprovidedbyUVISateachpixellocationmayberelatedtotheINCAENAfluxinacommonauroralsourceregionparameterspace.ThisproblemisconstrainedherebyassimilatingsimultaneousobservationsfromUVISandINCA,togetherwithmodelestimatesforneutraldensity,energeticparticledriftrates,atmosphericabsorption,andmagneticfluxequivalencemapping.
57
![Page 58: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/58.jpg)
EUVaurora’sresponsetosolarwindmeasuredwithHisaki&JunoKita,H.,TohokuUniv./ISASJAXAKimura,T.,Tao,C.,Tsuchiya,F.,Murakami,G.,Yamazaki,A.,Yoshioka,K.,Ebert,R.W.,Wilson,R.J.,Valek,P.W.,Clark,G.,Connerney,J.E.P.,Gladstone,R.,Kasaba,Y.,Yoshikawa,I.,Fujimoto,M.
WhiletheJovianmagnetosphereisknowntobedominatedbytheinternalsourceofplasmaandenergy,italsohasaninfluencefromthesolarwind.ThistalkmainlyfocussesonthesolarwindresponseofJupiter’saurora,whichisachievedbyHisakiandJuno.HisakiisanEUV/UVspacetelescopelaunchedin2013.ItsspectrometerEXCEED(ExtremeUltravioletSpectroscopeforExosphericDynamics)begancontinuousmonitoringofJupiterfromDec.2013.
WemadeastatisticalanalysisofthetotalpowervariationofJovianUVauroraobtainedfromHisaki.WecomparedthetotalUVauroralpowerin90-148nmwiththesolarwindmodel.PreviousobservationssuchasthosebytheHubbleSpaceTelescopeshowedthattheUVauroraandsolarwinddynamicpressurehad,attimes,apositivecorrelation.Fromthedataobtainedin2014-2015,theauroraltotalpowershowedapositivecorrelationtothedurationofaquiescentintervalofthesolarwindbeforetheenhancementsofthedynamicpressure.Itislargerthanthecorrelationtotheamplitudeofdynamicpressureenhancement.Asimilartrendwasidentifiedagainin2016whenHisakiobservedJupiterwithJunointheupstreamsolarwind.In-situsolarwindplasmameasurementbyJunowasusedforApril-June.Ontheotherhand,thedynamicpressurewasestimatedfromJuno-MAGdataforJan-Mar.WecalculatedcorrelationsbetweenJuno-MAGandthesolarwinddynamicpressureandusedtherelationshipwhensolarwindplasmadatawasnotavailable.
Onepossiblescenariotoexplaintheseresultsisthatthemagnetosphericplasmacontentcontrolstheauroraresponsetothesolarwindvariation.LongquiescentintervalwouldmeanthatthemagnetosphericplasmasuppliedfromIoismoreaccumulatedinthemagnetosphere.Thesolarwindcompressionofthemagnetosphereshiftstheplasmainwardandincreasestheplasmatemperatureanddensitybyadiabaticheating,whichleadstoanenhancementoftheauroralfield-alignedcurrentdensity.MasstransportatJupiterandSaturnKivelson,M.G.,Earth,Planetary,andSpaceSciences,UCLA,LosAngeles,CA90095-1567,USA
Themagnetospheresofthegasgiantplanets,JupiterandSaturn,owemanyoftheiruniquepropertiestotheneutralvaporsspewedoutofmoonsintheirdeepinteriors:IoatJupiter,EnceladusatSaturn.Theneutralsareionizedinthenear-equatorialmagnetosphereatandsomewhatbeyondtheorbitsofthemoons.Bothmagnetospheresdevelopquasi-steadystructurethatimpliesthattherateofplasmalossisonaveragethesameastherateofplasmainput.Itiswidelyagreedthatthewarmplasmaoftheinnermagnetospherediffusesoutwardataslowrate.Magneticfluxconservationrequiresthatasmuchfluxmoveinwardasoutwardanditislikelythattheinwardtransportofrapidlymovingdepletedfluxtubesprovidestherequiredbalance,buttheobservationssupportingthispicturequantitativelyareincomplete.Oncetransportedfromtheinnertotheoutermagnetosphere,theplasmamustbelostcompletelyfromthesystem,buthereagainquantitativeconfirmationofthelossmechanismisabsent.Candidateremovalmechanismsincludeplasmoidsthatcarryplasmadowntailoroutthemorning-sideboundaryand“drizzle”downthedusksideflank.Kelvin-Helmholtzvorticesontheflanksmayalsotransportplasmaoutofthedawnandduskflanks.Studiesofplasmoidssuggestthattheydonotaccountfortherequiredmasstransportratebutsimulationscallintoquestiontheadequacyofcoverageofthemeasurements.Drizzleispostulatedtooccurinregionsnotexploredbyspacecraft,andKelvin-Helmholtzobservationsremainincomplete.Thistalkwillconsiderwhatwedoanddon’tknowaboutthetransportprocess.
58
![Page 59: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/59.jpg)
HeatingJupiter’splasmatorus(Saturn’stoo)throughinterchangeKivelson,M.G.,EPSS,UCLA,LosAngeles,CA90095-1567Khurana,K.K.,andRamer,K.M.(deceased)
In1988,Smithetal.notedthatinJupiter’sequatorialmagnetosphereoutsideoftheorbitofIoobservedUVandEUVradiationcannotbemaintainedsolelythroughenergyinputbyionpickup,alludingtothisproblemasthe“energycrisis”oftheIoplasmatorus.Furthermore,thetemperatureofthetorusplasmaincreaseswithequatorialradialdistance(LRJ)(BagenalandDelamere,2011),eventhoughadiabaticheatingwouldleadtoadecreaseoftemperaturewithL.Smithetal.suggestedthatthemissingenergyis“carriedintothetorusbyinwardradialdiffusionoflow-density,hot[energiesgreaterthan300eV]ions,”throughwhattodaywewouldcallinterchange,estimatingthat1TWofpowerisavailablefromthisprocess.Returningtothisproblemandrequiringconservationofmagneticfluxtoestablishtransportrates,weusethepressureoftheenergeticplasmareportedbyBagenalandDelameretoestimatetherateofheattransportthroughtheIotorus.Wefindthatinterchangecanaccountforasmuchas15TWofpoweratJupiter,soinprinciplethemechanismcanwork.Perspicaciously,Smithetal.stated:“itiscrucialthat[theenergeticparticle]energy-losstimescalebeshorterthanorcomparabletotheirlifetimeagainstchargeexchangeiftheyaretoprovidetheneededenergy.”Furthermore,toheatthethermalplasmaoverarangeofradialdistances,theenergeticparticlesmustdriftoffthefluxtubesata“Goldilocks”rate,rapidlyenoughtodepositsomeenergyatL-valuesjustinsidetheirsourceregionandslowlyenoughthatanenergysourceremainsontheinward-movingfluxtubewhenitapproachesIo’sorbit.Onceonambientfluxtubes,thehotplasmaparticlesmusttransferenergytothewarmplasmabeforetheyarelostthroughchargeexchangeorotherprocesses.WewillprovideestimatesshowingthatthismechanismcanplausiblyaccountforpropertiesofthetorusplasmaandthatitalsoappliestoheatingofSaturn’sequatorialplasma.
59
![Page 60: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/60.jpg)
SpatialdistributionofatomicoxygenemissionsaroundIo'sorbitduringvolcanicallyquietandactiveperiodsKoga,R.,TohokuuniversityTsuchiya,F.,Kagitani,M.,Sakanoi,T.,Kimura,T.,Yoshikawa,I.,Yoshioka,K.,Yamazaki,A.,Murakami,G.,Smith,H.T.
Io’satmosphereismainlydominatedbysulfuroxidesthatoriginatedfromvolcanoes.TheyaredissociatedandsomeofoxygenandsulfuratomsescapefromIo’sgravitybyatmosphericsputtering,andcreateIo’sneutralcloudaroundIo’sorbit.ThespatialdistributionofIo’soxygenandsulfurneutralcloudhasnotbeenobservedbecausetheiremissionsarefaint(severalRayleighs(R)).ThankstothecontinuousobservationsofIoplasmatorusbyHisaki,wesucceedtoderivethespatialdistributionofatomicoxygenemissionsat130.4nmaroundIo’sorbit.
First,weanalyzedtheIophaseangle(IPA)dependenceandradialdistributionofatomicoxygenemissionduringavolcanicallyquietperiod(fromNovembertoDecember,2014).TheresultsshowIo’sneutraloxygencloudconsistsoftwocomponents,aleadingcloudthatspreadsinsideIo’sorbit(called“bananacloud”)andalongitudinallyuniform,diffuseregiondistributedalongIo’sorbit.Wealsofindthecloudspreadsatleast7.6RJfromJupiter.Weestimatedatomicoxygennumberdensity(40-80cm-3)andoxygenplasmasourcerate(410kg/s)fromlongitudinallyaveragedradialprofileofOIemissions.TheestimationisconsistentwithpreviousmodelstudiesbasedonthespectraldiagnosisofemissionionsobservedbyCassiniandHisaki.
WeobservedtheenhancementofatomicoxygenemissionsaroundIointhespringof2015.Inthesameperiods,theenhancementofinfraredemissionfromIo’svolcanoandextendedsodiumnebulaemissionwerealsoobserved.ThisshowsthevolcanicactivityincreasesneutralgasesoriginatedfromIo.WeanalyzedtimevariationsofIPAdependenceofOIemissionsevery10daysandfindboththebananacloudandthediffuseregionincreaseinthesamerate.ThisshowsoxygenatomsescapefromIospreaddiffuseregionfasterthan10days.TheresultisconsistentwithIo’sescapevelocity(2.6km/s).
60
![Page 61: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/61.jpg)
TheionradiationbeltsofJupiterandSaturnKollmann,P.,JHU/APLRoussos,E.;Kotova,A.;Regoli,L.;Paranicas,C.;Clark,G.;Nenon,Q.;Mauk,B.;Krupp,N.;Mitchell,D.G.;Haggerty,D.;Rymer,A.M.;Carbary,J.;Connerney,J.E.P.
Planetaryradiationbeltsareregionsofquasi-stablytrappedchargedparticlesfromthehundredsofkeVprobablyintothehundredsofMeV.Even60yearsafterthediscoveryofEarth’sradiationbelts,whichwasthefirstdiscoveryofthespaceage,wearenotdonediscovering:WithinthelasttwoyearstheJunoandCassinimissionsfoundentirelynewradiationbeltsclosetotheatmospheresoftheseplanets.TheoriginandphysicalprocessesinthesenewbeltsareasfundamentallydifferentfromthepreviouslyknownbeltsaroundtheseplanetsassomeoftheirbeltsdifferfromwhatweknewfromEarth.
EvenduringitsfirstsciencepassaroundJupiter,Juno’sJEDIinstrumentdiscoveredanewionradiationbeltinwardofthebeltsthatweremeasuredbytheGalileoProbeathigherenergies.ThemorerecentJunoorbitsreachdowntosufficientlylowlatitudestodetectalsotheradiationbeltsinwardofabout3RJ.ThenewJunomeasurementsareatlowerenergiesthantheGalileoProbeandhaveaclearionspeciesidentification,whichcanprovideinsightsintotheoriginoftheseradiationbelts.
Duringtheproximalphaseofitsmission,Cassini’sMIMIinstrumentdiscoveredanothernewradiationbeltlocatedinwardofthemainrings.Thein-situmeasurementsshowedMeVandGeVprotonsindicatingthatthekeVionsdetectedremotelyearlieroriginatefromloweraltitudesthanwerereachedbyCassini.
InthistalkwewillprovideanintroductionintothephysicalmechanismsthatsupplyMeVionstothegiantplanetradiationbeltsandareresponsiblefortheirevolution.Wewillillustrateourdiscussionwithdatafrommissionstotheseplanets.
ThisintroductionwillleadtorecentresultsonJupiter’sinnerionbelts,asdeterminedfromthecombinationofmission-longJuno/JEDImeasurementswitharecenthigher-ordermagneticfieldmodel.WewillalsoprovideanupdatetoouranalysisonSaturn’sinnermostradiationbeltfoundduringthelastCassiniorbits.
61
![Page 62: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/62.jpg)
FieldsandParticlesInvestigationsbytheEuropaClipperMissionKorth,H.,JohnsHopkinsUniversityAppliedPhysicsLaboratoryPappalardo,R.T.,Senske,D.A.,Kempf,S.,Raymond,C.A.,Waite,J.H.,Westlake,J.H.,EuropaClipperScienceTeam
TheEuropaClippermissionwillexploreJupiter’sicysatelliteEuropatoinvestigateitshabitability.Themission’sscienceobjectiveswillbeaccomplishedusingasuiteofremote-sensingandin-situinstruments,thelatterprovidingobservationsofthemagneticfieldandparticleenvironmentsnearEuropaand,forcomparison,throughoutthesampledregionoftheJovianmagnetosphere.TheInteriorCharacterizationofEuropausingMagnetometry(ICEMAG)investigationwillmeasuremagneticfieldsgeneratedbycurrentsinducedinEuropa’ssubsurfaceocean,ionizedmaterialejectedfromanyplumes,andelectromagneticcouplingofthemoontoJupiter.ThePlasmaInstrumentforMagneticSounding(PIMS)willmeasureionsandelectronsinEuropa’satmospheretoinferthecontributionstothemagneticfieldfromplasmacurrentsandtounderstandtheinteractionandcouplingoftheplasmawiththemoon’ssurfaceandwithJupiter.TheMAssSpectrometerforPlanetaryExploration(MASPEX)measurestraceneutralspeciestodeterminethecompositioninEuropa’ssputter-producedexosphereandpotentialplumes.Finally,theSUrfaceDustAnalyzer(SUDA)willmapthechemicalcompositionofparticlesejectedfromEuropa’ssurfaceandidentifythemakeupofpotentialplumesbydirectlysamplingmicroscopicparticlesoriginatingfromthesurface,entrainedintheplumes,ordeliveredfromelsewherewithinoroutsidetheJoviansystem.Themissionplanimplementsasynergisticsetofobservationsamongtheseinstrumentstocharacterizetheice-shellthickness,oceanthicknessandsalinity,compositionofmaterialsmakingupEuropa’ssurfaceanditssubsurfaceocean,andanycurrentplumeactivity.Wepresentthesuiteofin-situinstrumentsandthemissionplanthatimplementsthemeasurementsrequiredtomeetthescienceobjectivesoftheEuropaClippermission.
Saturn’sthermospherefromCassini/UVISGrandFinalestellaroccultationsKoskinen,T.T.,LPL,UniveristyofArizonaBrown,Z.L.,West,R.A.,Jouchoux,A.,Esposito,L.W.
AglobalpictureofSaturn'supperatmosphereisnecessarytounderstandthedynamics,energybalanceandminorspeciescompositioninthethermosphere.OccultationdatafromVoyager/UVSandCassini/UVIShavebeenusedtostudythispoorlyknownregionoftheatmosphere.Thepreviousdata,however,arelargelyconcentratedatlowtomid-latitudesandwereobtainedsporadicallyatdifferenttimes,complicatingtheseparationoftemporalandspatialtrends.TheGrandFinaleoccultationsovercometheselimitationsasmostofthedatawereobtainedwithinsixweeksinthesummerof2017.Togetherwiththeobservationsfrom2016,theyprovideavitalnewlookatmeridionaltrendsinSaturn'sthermosphere.Wepresenttemperatureanddensityprofilesretrievedfromtheseoccultations,includingourfirstlookatthepolarthermosphere.
62
![Page 63: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/63.jpg)
FutureJovianMagnetosphericsciencewithJUICEKrupp,N.,MaxPlanckInstituteforSolarSystemResearchMasters,A.;Witasse,O.;Barabash,S.;Wahlund,J.-E.;Dougherty,M.K.;Gladstone,R.
JUICEisthefirstlargemissionintheESACosmicVisionprogram.Thespacecraftwillbelaunchedin2022andwillarriveatJupiterin2029.ItwillspendthreeyearscharacterizingtheJoviansystem,theplanetitself,itsgiantmagnetosphere,andtheicymoonsGanymede,Callisto,andEuropa.JUICEwillthenorbitGanymedeasthefirstspacecraftinhistoryforalmostayear.
Themaingoalofthemissionistoexploretheemergenceofhabitableworldsaroundgasgiants.WhileGanymedeisinthefocusoftheJUICE-missionalsothemagnetosphereofJupiterwillbestudiedingreatdetail.Thelong-termmagnetosphericsciencewillpushsignificantlybeyondthecapabilitiesofpreviousmissions.JUICEwillexploreJupiter’sequatorialmagnetospherecoveringawiderangeoflocaltimesandradialdistancestostudytheglobalandlocalmagnetosphericparameters,butthespacecraftwillalsostudyhigherlatitudesupto30degreestoexploretheregionsaboveandbelowthemagnetodisc,studyremotelytheringcurrentandtheJovianaurora.
WewillshowhowJUICEwillcarryoutitsmagnetosphericsciencegoaltocharacterizetheJovianenvironmentbystudyingthemagnetosphereasafastrotatorandagiantacceleratoraswellastryingtounderstandthemoonsassourcesandsinksofmagnetosphericplasma.Inaddition,wewillelaboratethesecondmagnetosphericsciencegoalofJUICEtocharacterizethemagnetosphereofGanymedeinunprecedenteddetailsincludingtheinteractionbetweenbothmagnetospheres.NovelElectronDistributionFunctionsAssociatedwithaSourceofBroadbandKilometricRadiationatJupiterKurth,W.S.,UniversityofIowaLouarn,P.,Imai,M.,Hospodarsky,G.B.,Allegrini,F.,Valek,P.,Connerney,J.E.P.,Kotsiaros,S.,Gladstone,G.R.,Adriani,A.,Mauk,B.H.,Louis,C.,Zarka,P.,andBolton,S.J.
Juno'spolarorbitmakesinsituobservationsofJovianauroralradioemissionsourcespossible.Whileitisgenerallyagreedthattheseradioemissionsaregeneratedviathecyclotronmaserinstability,itisimportanttounderstandthenatureoftheunstableelectrondistributionsforcomparisonswiththoseatEarthandasextraterrestrialexamplesofacommonastrophysicalradiosourcemechanism.DuringJuno'seleventhperijove(PJ11)on7February(Day038)2018,Junocrossedasourceofbroadbandkilometricradiationatabout80kHzduringanapproachtothesouthernmainauroraloval.Identificationofthesourcecomesfromnotingthatthelow-frequencylimitoftheradioemissionat18:12:58isnearly2%belowtheelectroncyclotronfrequency.Duringthisevent,therewasadearthoflowenergyplasma,suggestingaplasmacavity.Nearby,aringdistributionofelectronsaboveafewkeVwasmeasuredbytheJunoAuroralDistributionsExperiment.Thiselectrondistributionwascertainlyhighlyunstableandpossiblysimilartoso-calledhorseshoedistributionsinEarth'sauroralradiosources.Theradiosourceisalsocoincidentwithadeflectioninthemagneticfieldconsistentwithanauroralcurrentsystem.
63
![Page 64: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/64.jpg)
AbriefoverviewofauroralprocessesonUranusandNeptuneLamy,L.,LESIA,ObservatoiredeParis
OurcurrentknowledgeofauroralprocessesprevailingonthemagnetictwinsUranusandNeptune,andoftheunderlyingsolarwind-magnetosphere-ionosphereinteraction,stillmostlyreliesonVoyager2radio/UVandinsituobservationsobtainedduringtheflybyofeachplanet,respectivelyin1986andin1989.Theseobservationswereadditionallyacquiredatepochscorrespondingtospecificsolarwind/magnetosphereconfigurations,expectedtovarysignificantlyforbothplanetsalongtheirrevolutionaroundtheSun.Fortunately,whilewaitingforfutureindepthexplorationmissionsoficegiantplanets,someadditionalclueswerein-betweenobtainedfromremotelong-termEarth-basedUV/IRobservationswhichsampleddifferentseasons.TheaimofthispresentationistostartfromtheVoyager2originalpicturebeforetointroducemorerecentresultsuptothelatestmulti-spectralobservingcampaignsexecutedatbothplanetslate2017.ThelowfrequencysourceofSaturn’sKilometricRadiationLamy,L.,LESIA,ObservatoiredeParisP.Zarka,B.Cecconi,R.Prangé,W.Kurth,G.Hospodarsky,A.Persoon,M.Morooka,J.-E.WahlundandG.Hunt
Understandingthegenerationofplanetaryauroralradioemissions,thepowerfulnon-thermalradiationsproducedbyallthemagnetizedplanetsexploredsofar,andactivelysearchedfromexoplanetsandmoremassiveobjects,requiresinsitumeasurementsfromwithintheirsourceregion.Duringthering-grazinghigh-inclinationorbitsspanninglate2016toearly2017,theCassinispacecraftsampledatthreeoccasionsthetopofSaturn’sKilometricRadiation(SKR)emissionregion,whoseintensificationshavelongbeenusedasasensitiveproxyoflarge-scalemagnetosphericdynamics.Thenarrow-bandedradiosourceswerecrossedatfrequenciesof10-20kHz,allinthenortherndawn-sidesector.Theyhostedextraordinarymodeemission,radiatedquasi-perpendicularlytothelocalmagneticfieldfrom6-12keVelectron-beamsconsistentwiththeCyclotronMasterInstabilityandembeddedwithinregionsofupwardcurrentsthemselvescoincidentwiththemainauroraloval.Overall,theSKRlowfrequencysourcesappeartobestronglycontrolledbytime-variableelectrondensities.
64
![Page 65: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/65.jpg)
CorrectingGalileo’sEnergeticParticleDetector(EPD)data;MethodologyandImplications.Lee-Payne,Z,AberystwythUniversityGrannde,M
Overthecourseofits8-yearmissiontheEnergeticParticleDetectorontheGalileosatellite,launchedin1989,tookdataontheJovianParticleenvironment.Inthehighradiationenvironment,theEPD’sCompositionMeasurementSystem(CMS)degradedovertime;highermassparticles,specificallyoxygenandsulphur,readatfarlowerenergiesandcountratesatlaterepochsinthemissions.Byconsideringthenon-steadyaccumulationofdamageinthedetector,aswellastheoperationoftheprioritychanneldatarecordingsysteminplaceontheEPD,acorrectioncanbemade.Amodelofdeadlayerbuild-upinsemiconductor-detectorsisbuilt,basedonSRIMresults,andthenusedtoreversetheeffectsofthebuild-up.Theresultassignsanestimationofdead-layerdepthduringthemissiondatarecordings,andisusedtoproduceacorrectedversionofboththehighratedataandrealtimecountratesofallchannels.Theinferredsulphurabundancesareincreased.EnergeticiondynamicsnearCallistoLiuzzo,L.,GeorgiaInstituteofTechnologySimon,S.
WeexaminethedynamicsofmagnetosphericenergeticionsinthehighlyperturbedandasymmetricelectromagneticenvironmentoftheJovianmoonCallisto.TheAlfvenicinteractionofthe(nearly)corotatingmagnetosphericplasmawithCallisto'sionosphereandinduceddipolefieldgenerateselectromagneticfieldperturbationsnearthemoon,thestructureofwhichvariesasafunctionofCallisto'sorbitalposition.Forthisstudy,theseperturbationsareobtainedfromtheAIKEFhybridmodel(kineticions,fluidelectrons)whichhasalreadybeensuccessfullyappliedtoCallisto'slocalplasmaenvironment(Liuzzoetal.,2015,2016,2017).ToisolatetheinfluenceofCallisto'sionosphereandinduceddipolefieldonenergeticiondynamics,weanalyzethetrajectoriesofenergeticH+,O++,andS+++ionsforvariousconfigurationsofthelocalelectromagneticfields.WepresentspatiallyresolvedsurfacemapsthatdisplayaccessibilityoftheseionpopulationstoCallistoatselectenergiesfrom1keVto5000keV.TheAlfvenicinteractionwith(i)Callisto'sionosphere,(ii)Callisto'sinducedfield,and(iii)thecombinationofboth,allleavedistinctimprintsintheseaccessibilitypatterns.ThemagnetosphericfieldlinedrapingaroundCallisto'sionospherepartiallyshieldsthemoon'strailinghemispherefromenergeticionimpacts,andtheinducedfieldtendstofocusenergeticionimpactsnearCallisto'sJupiter-facingandJupiter-avertedapices.DependingonthenatureofCallisto'sAlfvenicplasmainteraction,theaccessibilityofitssurfacetoenergeticprotonsmayevolvenon-monotonicallywithincreasingenergy.Additionally,wecalculatemapsofenergeticionaccessibilityandtheresultingenergydepositionontoCallistoatthetimeoftheGalileoC3,C9,andC10flybys.
65
![Page 66: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/66.jpg)
AcomprehensivepictureofCallisto'smagneticandcoldplasmaenvironmentduringtheGalileoera:ImplicationsforJUICELiuzzo,L.,GeorgiaInstituteofTechnologySimon,S.
WeapplydataanalysistechniquesandhybridmodelingtostudyCallisto’sinteractionwithJupiter’smagnetosphere.MagnetometerdatafromtheC3andC9Galileoflybyshadbeenexplainedwithapureinductionmodel,astheplasmainteractionwasweak.Weexpandthisanalysistoincludetheremainingfiveflybys(C10,C21,C22,C23,C30)wheretheplasmainteractionwasnon-negligible.WethereforeconsidercontributionstoCallisto’smagneticenvironmentgeneratedbyinductionaswellastheplasmainteraction.Wehaveidentifiedaquasi-dipolar“coreregion”nearCallisto’swakesidesurface,dominatedbyinductionandpartiallyshieldedfromtheplasmainteraction.Outsideofthisregion,Callisto’smagneticenvironmentischaracterizedbyfieldlinedraping.FutureflybysduringtheupcomingJUICEmissionmaysamplethewakeside“coreregion”tobetterconstraintheconductivity,thickness,anddepthofCallisto’ssubsurfaceocean.Ouranalysisalsoshowsthatevenduringasingleflyby,variousnon-stationaritiesintheupstreamenvironmentmaybepresentnearCallisto,whichmaypartiallyobscurethemagneticsignatureofthemoon’ssubsurfaceocean.Overall,ourstudyprovidesacompletethree-dimensionalpictureofCallisto’smagneticenvironmentduringtheGalileoera,basedonallavailablemagnetometerdatafromtheGalileoflybys.WeapplyourunderstandingtothefutureJUICEflybysofCallistotodeterminewhichencounterswillbebesttoidentifyCallisto’sinductiveresponseinmagnetometerdata.AninvestigationintoradialandazimuthalcurrentsinJupiter'sMagnetodiscLorch,C,UniversityofLancaster,UKRay,L.C.Arridge,C.Martin,C.Bader,A
Jupiter’smagnetosphereandatmospherearecoupledviafield-alignedcurrentsthatflowalongtheplanetarymagneticfield,moveradiallyoutwardthroughthemagnetodiscandreturnbacktotheplanet,finallyclosingintheionosphere.Magnetosphere-ionosphere(MI)couplingisaffectedbylocaltimevariationsinthemagnetosphericcurrentswithinthemagnetodiscas∇·J=0.ProducingamapofthevariationsinthesecurrentsisimportantforunderstandingthemechanismswhichinfluencethemainauroralfeaturesobservedatJupiter.Khurana[2001]determinedtheradialandazimuthalcurrentswithinthemagnetodiscusingallavailablemagnetometerdatafromVoyager1&2,Pioneer10&11,Ulysses,andGalileothroughtoMay31st,2000.HereweextendupontheKhurana[2001]analysistoincludeallavailableGalileomagnetometerdatainordertoproduceamorecompletemapoftheradialandazimuthalcurrentsforallavailablelocaltimes.WeusetheVIP4modeloftheinternalmagneticfield(Connerneyetal.[1998])andaJupitercenteredlocalcurrentsheetreferenceframetoinvestigatethemagnetodisccurrents.Furthermore,wemakeacom-parisonbetweentheresultsobtainedusingtheKhurana[2001]currentsheetmodelandthemorerecentKhurana&Schwarzl[2005]currentsheetmodel,whichallowsthecurrentsheettobecomeparalleltothesolarwindatlargedistances.
66
![Page 67: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/67.jpg)
Onthesaturationmechanismsofthecyclotronmaserinstability-AninvestigationwithJunoLouarn,P.,IRAP/CNRSKurth,W.S.,Allegrini,F.,McComas,D.J.,Valek,P.W.,André,A.,Bagenal,F.,Bolton,S.,Connerney,J.,Ebert,R.W.,Imai,M.,Levin,S.,Szalay,J.R.,Wilson,R.J.
Junoplasma,waveandmagneticfieldobservations(JADE,WavesandMAGinstruments)haveconfirmedthatthecyclotronmaserinstabilityisthegenerationmechanismofthejovianauroralradioemissions,from10skHzto10sMhz.Afundamentalquestionconcernsitssaturationmechanism.Howis,infine,theintensityoftheradiowavesdetermined?Bywhatphysicalprocesses?Answeringthesequestionsisakeystepinprogresstowardsaquantitativetheoryoftheradioemissiongeneration.WeshowthatJunoobservationsofferasplendidopportunityforbetterunderstandingthesaturationmechanisms.UsingtheelectrondistributionfunctionsmeasuredbyJADE,onecanindeedusethecyclotronmasertheorytocalculatethenormalizedgrowthrate(theratiobetweenthegrowthandthegyrofrequency).Typicalvaluesof10-3areobtainedmeaningthatthetruegrowthratesvarybyalmost3ordersofmagnitude,fromafew100sHzto100kHz,dependingoftheradiodomains(deca,hectoandkilometric).Thesehugedifferencesshouldcorrespondtovarioustypesofsaturationmechanisms,includingsimpleconvectionoutofthesourceregion,quasi-linearrelaxationorthenon-lineartrappingtheory.Thesepossibilitiesareinvestigatedandcomparedwithwaveandparticleobservations.
Jupiterauroralemissions:statisticaldistibutionofradiosourcesLouis,C.,LESIA,ObservatoiredeParisP.Zarka,L.Lamy,S.Hess,R.Prangé,M.Imai,W.Kurth
InthisstudyweareinterestedinthepositionofthesourcesproducingtheJupiter'sauroralradioemissions.WehavepickupallthesourcescrossedfortheperijovesdoneyetbyJuno.Thisallowedustomaptheradiosources,aswellasassociatedmagneticfieldlines,overtheentirefrequencyrangecoveredbyJuno/Waves(50Hz-40MHz).ThecomparisonwithmagneticfieldmodelsandUVimages(Juno/UVSandHubble/STIS)revealedacorrelationbetweentheUVemissionofthemainovalandtheidentifiedradiosources(kilometric,hectometricanddecametric).
67
![Page 68: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/68.jpg)
AlfvenicAuroraatEarthandJupiterLysak,R.L.,UniversityofMinnesotaSong,Y.
ObservationsfromJunohaveyieldedunprecedentednewdetailabouttheacceleratedplasmapopulationsthatproduceJupiter’saurora.ManyofthesefeaturesarefamiliartothoseatEarth;however,therearealsomajordifferences.Bothinverted-Vandbroadbandtypeaccelerationmechanismsareobserved,althoughthebroadbandprecipitationseemstobemoredominantatJupiter.AtEarth,suchbroadbandaccelerationofparticlesisgenerallyassociatedwithtime-dependentaccelerationinkineticAlfvenwaves,whichdevelopaparallelelectricfieldinlow-betaplasmasduetoelectroninertiaandinthemoderatebetaregimeduetoelectronpressureandLandaudamping.Thus,theauroralemissionsassociatedwiththisbroadbandprecipitationareoftencalledtheAlfvenicaurora.GiventhedynamicnatureoftheauroraasobservedbyJuno,itislikelythatsimilarmechanismstakeplaceatJupiter.Anotherquestionistherelationshipbetweenbroadbandandinverted-Vprecipitation.AtEarthitappearsthattheAlfvenicauroraoccursintransitionregionssuchastheplasmasheetboundarylayerandduringsubstormonset,anditisreasonabletosupposethatthisisatransitionalstateandcanevolveintoamorestaticinverted-VtypeofaccelerationwhenasteadysupplyofPoyntingfluxcanbemaintained.However,atJupiter,theredoesnotappeartobethetypeoflarge-scalesteadycurrentsystemsthatappearatEarth,whichmayberelatedtotherelativelackofinverted-Vpopulations.Thelackofalarge-scalesystemassociatedwiththebreakdownofco-rotation,andthepatchynatureoftheaurorainthemainoval,suggeststhatthisregionoflargevelocityshearmaybeunstabletoinstabilitiesoftheinterchangetype.PotentialcandidatesforthisinstabilitywillbeinvestigatedandtheirpotentialforunderstandingtheJovianaurorawillbeassessed.Long-termvariationsandcorrelationsofJovianradiocomponentsMagalhaes,F.P.,NationalInstituteofSpaceResearch(INPE/Brazil)Magalhaes,F.P.;Echer,E.;Zarka,P.;Marques,M.S.;Dabidin,;Cecconi,B.;Louis,C;Lamy,L.;Kurthetal.
Jupiterhasastrongmagneticfieldandacomplexmagnetosphere.Asaconsequence,ithasverydiversezooofintenseradioemissions.Thehighlatitudeemissionsextendfromkilometrictodecametricwavelengths(bKOM,HOMandDAMcomponents).TheDAMcomponentisitselfsplitinemissionsthatarecontrolledbysatellite-Jupiterinteraction(Io,Europa,Ganymede)andauroralemissions.Moreover,nKOMemissionhasitsoriginintheIoplasmatorus.Inspiteofseveraldecadesofsatelliteobservations,therelationbetweenthesecomponents,andtheirlinktomagnetosphericdisturbances(internal,i.e.essentiallyIorelated,orexternal,i.e.solarwindrelated),isnotfullyunderstood.WehaveconductedadetailedanalysisofRPWSdatarecordedduringtheCassini-Jupiterflyby(fromOct.1st,2000toApril1st,2001).Thedatawerereduced,calibratedanddetrended(fordistance-relatedvariations),andacatalogofalloccurrencesofallradiocomponents(theaboveJovianonesandsolarTypeIIIbursts)wascreatedfromameticulousvisualselectionbasedontheirwellknowntime-frequencymorphology.Basedonthisselection,robustcorrelationsbetweencomponents(evenwhentheysharethesamefrequencyrange),spectralanalysesoftheirtimeseries,andstackedlongitude-frequencydynamicspectrawereperformed.CorrelationstudiesallowustoaddresstherelationbetweentheIotorusactivity(nKOM,Io-DAM)andtheauroralactivity(bKOM,HOM,DAM).SpectralanalysesallowustoaddressperiodicitiesrelatedtoSystemIIIversusSystemIVmodulations,aswellaslongerperiodsrelatedtoIo'svolcanismorthesolarwind.Stackeddynamicspectraprovide"signatures"ofeachradiocomponent,thatweattempstointerpretintermsofsourcelocationandbeamingproperties,inrelationwithmagnetosphericdynamics.Cassini-RPWSdataarefurthercorrelatedwiththeNancaylongtermDAMdatabase,andacomplementaryanalysishasstartedbasedonJuno-Wavesdata.
68
![Page 69: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/69.jpg)
StandingAlfvénwavesinJupiter'smagnetosphereasasourceof~10-60minutequasi-periodicpulsationsManners,H.,ImperialCollegeLondonMasters,A.
Jupiter’sgiantmagnetosphereexhibitsmanyphenomenathataredifficulttoexplain,andquasi-periodic(QP)pulsationsintheultra-low-frequency(ULF)bandhaveprovenespeciallymysterious.SincetheVoyagerera,alargebodyofULFmeasurementshasemergedwithperiodicities10-60minutes,spanningmagnetic,X-Ray,radioandplasmawaveperturbations.
PreviouspublicationsproposedtreatingULFmagneticperturbationsasstandingAlfvénwavesonJupiter’smagneticfieldlines.Inthisproposal,pulsationsareproducedwhencompressionalperturbationscoupletotransversemodes.Thesetransversewavesarereflectedbytheionosphere,therebyestablishingresonantfieldlineharmonics.Theresonantfieldlinesthenmodulatevariousprocessestoproducetheobservedpulsations.
WhetherallULFpulsationsaretheresultofthesamephenomenonhasbeenthesubjectofdebate.Furtherinvestigationintohowthedynamicsofthemagnetosphereaffecttheeigenperiodsofresonantfieldlinesisrequiredtoexplaintherangeofperiodicityinthereportedpulsations.
WehaveusedamagnetosphericboxmodeltocomputethenaturalperiodsoftheJovianmagnetosphereforvaryingequatorialplasmasheetconditions.Largeuncertaintiesinthespatialextentandplasmadensityoftheplasmasheetproduceabroadrangeofnaturalperiods.Theseuncertaintiesalsomeancontributionsfromeachharmonicareindistinguishableinouranalysis.Excludingthefundamentalmode,thefirsthalf-dozen(andpotentiallymore)harmonicshaveeigenperiodsof10-60minutes.WesuggestthatallsuchJovianULFphenomenamaybetheresultofstandingAlfvénwavesonJupiter'smagneticfieldlines.CurrentdensityinSaturn’sEquatorialCurrentSheetMartin,C.J.,PhysicsDepartment,LancasterUniversity,Lancaster,UKArridge,C.S.
Saturn’sequatorialcurrentsheetexhibitsanumberofperiodicmovementsassociatedwiththeseasonsandtheplanetaryrotationrate,alongwithaperiodicmovementsofacurrentlyunknownorigin.TheseaperiodicmovementsofthemagnetodiscareutilisedtocalculatetheheightintegratedcurrentdensityofthecurrentsheetusingamodifiedHarrissheetdeformedbyaGaussianwavefunction.Wefindalargeasymmetryintheradialheightintegratedcurrentdensityattributedtosweptforwardandsweptbackwardsfieldintheduskanddawnsectorsrespectively.WenotethatthisrelationshipisverysimilartowhatisseenatJupiterandcommentonthespatialversustemporaldifferencesinthecurrentdensityatSaturn.Additionally,acomparisonofSaturn,JupiterandEarth’sazimuthalandradialequatorialcurrentsarediscussed,andwefindthatSaturnexhibitssimilaritieswithboth.
69
![Page 70: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/70.jpg)
StatisticalAnalysisofFluxRopesinTitan’sIonosphere:Acomparisonofforce-freeandnon-force-freemethodsMartin,C.J.,PhysicsDepartment,LancasterUniversity,Lancaster,UKArridge,C.S.,Badman,S.V.,Wei,H.Y.,Russell,C.T.,Dougherty,M.K.
Fluxropesareacommonfeatureinmagnetisedplasmaregimesalloverthesolarsystem.85fluxropesareidentifiedusingtheCassinimagnetometerduringallofCassini’sTitanflybys.Weutiliseaforce-freefluxropemodeltoextractvaluesforthecorefieldofthefluxropeandtheradii,andcomparethesevaluesandthegoodnessoffittoanon-force-freemodelthatallowsthecurrentsgeneratedinthefluxropetobeanalysed.BothmethodsfitthefluxropesfoundinTitan’sionosphere,howeverthenon-force-freefluxropealongwithit’sassumptionsshowamuchimprovedfittoTitan’sfluxropesthantheforce-freemethod.Wediscussthephysicalmechanismsassociatedwiththeproductionandmaturationofthesefluxropesandcommentontheirvariability,alongwiththevariabilityofSaturn’smagnetosphericenvironmentatTitan’sorbit.ThemagnetospheresofUranusandNeptuneMasters,A.,ImperialCollegeLondon
ThemysteriousmagnetospheresofUranusandNeptunehavebarelybeenexploredbyspacecraft,yettheyaredistinctfromallothersolarsystemmagnetospheresinmanyrespects.Understandingthephysicsofthesemagnetospheresiscentraltounderstandinghowenergyflowsthrougheachglobal,coupledplanetarysystem.Hereweintroducethesehighlyasymmetricanddynamicicegiantmagnetospheres.WereviewwhatwelearnedfromthesnapshotofeachsystembyVoyager2inthe1980sandwhatwehavelearnedsince,focusingonthekeyopenquestionsthatwemustanswerinordertodeterminehoweachofthesemagnetosphericsystemsworks.Wewillconcludewithadiscussionofongoingpreparationandlobbyingforafuturemissiontooneofthesedistantplanets,wheremagnetosphericsciencemustbeamajordriver.
70
![Page 71: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/71.jpg)
Amoreviscous-likesolarwindinteractionwithallthegiantplanets?Masters,A.,ImperialCollegeLondon
Identifyingandquantifyingthedifferentdriversofenergyflowthroughaplanetarymagnetosphereiscrucialforunderstandinghoweachcoupledplanetarysystemworks.Themagnetosphereofourownplanetisdrivenexternallybythesolarwindviaglobalmagneticreconnection,aswellasthroughaviscous-likeinteractionunderpinnedbygrowthoftheKelvin-Helmholtzinstabilityasasecondaryeffect.Hereweshowthattherelativeimportanceofexternaldrivingbyaviscous-likeinteractionisexpectedtobegreateratthegiantplanetarymagnetospheresintheouterSolarSystem.WedemonstratethatthisresultsfromcombiningpresentunderstandingofthefundamentalprocessesinvolvedwiththeestablishedscalingoftypicalsolarwindparameterswithdistancefromtheSun.Ourresultssupportthepossibilityofaprimarilyviscous-likeinteractionbetweenthesolarwindandthegiantplanetmagnetospheres,asproposedbypreviousauthorsandincontrastwiththesolarwind-magnetosphereinteractionatEarth.AuroralaccelerationatJupiteranditspossibleroleincreatingJupiter’suniquelyenergeticradiationbeltsMauk,B.H.,TheJohnsHopkinsUniversityAppliedPhysicsLaboratoryHaggerty,D.K.,Paranicas,C.P.,Clark,G.B.,Kollmann,P.,Rymer,A.M.,Bolton,S.J.Levin,S.M.,Adriani,A.,Allegrini,F.,Bagenal,F.,Becker,H.N.,Bonfond,B.,Connerney,J.E.P.,Ebert,R.W.,Elliott,S.S.,Gladstone,G.R.,Kurth,W.S.,McComas,D.J.,Ranquist,D.,Valek,P.W.
TheelectronaccelerationprocessesthatgenerateJupiter’suniquelypowerfulauroraareunexpectedlydiverse.Broadbandacceleration,likelystochastic,providesthegreatestdownwardelectronenergyfluxesoverJupiter’smainauroralregions.Butelectricpotentialsalongthemainauroralfieldlinesaresometimespresent,attimesexceeding400kVineithertheupwardordownwarddirections.Hugedownwardelectronenergyfluxesareunexpectedlyobservedontheverysamefieldlineswherehugeelectricpotentialsarealsoacceleratingdownwardenergybeamsofprotons.Usingthemagneticfield-alignedpotentialdirectionalityasaproxyforthedirectionalityofmagneticfield-alignedelectriccurrents,themagnitudeofthedownwardelectronenergyfluxessurprisinglydoesnotseemtocareaboutthedirectionalityoftheelectriccurrents.Butthedirectionalityoftheelectricpotentialsdoesseemtoplayaroleindeterminingthecharacterofthebroadbandaccelerationprocessesandparticularlyintheup-downasymmetriesintheaccelerationprocesses.Surprisingly,evenoververyintenseUVaurora,theupwardaccelerationofelectronscanbecomparableandevengreaterthanthedownwardacceleration.Andmoresurprisingstill,theintensityoftheupwardlyacceleratedelectronsatMeVenergiescanbeasmuchas2ordersofmagnitudegreaterthantheintensityofJupiter’sradiationbelts.Basedonthatfinding,weexploreherethepossibilitythat,atJupiter,auroralaccelerationrepresentsthefirstaccelerationstepinthegenerationofJupiter’suniquelyenergeticradiationbelts.
71
![Page 72: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/72.jpg)
AnomalousPlasmaWavesObservedDuringCassini'sRing-grazingOrbitsMenietti,J.D.,UniversityofIowaPisa,D.,Sulaiman,A.H.,Averkamp,T.F.,Kurth,W.S.
InthefinalperiodoftheCassinimissionthespacecrafttrajectoryincluded20highinclinationring-grazingorbits.TheseorbitstraversedtheinneredgeoftheEnceladustorus,aregionofintenseZ-modeandnarrowbandemissionaswellasintenseupperhybridresonanceemission.Thelattersometimeshaveanomalousappearance,andcanbeassociatedwithsourcesofintenseelectromagneticemission.WehavesingledoutsimilaranomalousemissionwhichoccurredoccasionallyonpreviousCassiniorbitsthatlieclosetotheregiontraversedbythering-grazingorbits.ThesepreviousorbitsareimportantbecausewehaveaccesstoCassinielectronphasespacedistributionsforwhichwecanperformdispersionanalysistobetterunderstandthefreeenergysourceandinstabilityoftheanomalousemission.Webelievethisemissionmaysometimesbeassociatedwithdensityanomaliesandstrongdensitygradientsneartheringplane.Inthispaperwediscussourinitialresults.IdentificationofJupiter'shectometricradiationassociatedwithreconnectioninthemagnesphereMisawa,H.,GraduateSchoolofScience,TohokuUniversityTsuchiya,F.,Mizuguchi,T.
ItisknownthatJupiter'sradioemissioninthehectometricwaverange(HOM)showstwotypeoccurrencecomponents.Oneisacomponentrelatingtosolarwindvariations(sw-HOM)appearingaroundCML(CentralMeliansystemIIILongitudeofanobserver)=180degwhensolarwindpressureenhances.Anotheroneisgenerallymoreintensethansw-HOMandhasnoorweakrelationwithsolarwindvariations(nsw-HOM)appearingaroundCML=110degand280degasthetwomajorcomponentswhenDe(Jovicentricdeclinationofanobserver)=-1deg(Nakagawa,2003).Thensw-HOMisthoughttobegeneratedbysomeinternalprocessesinitiatedbytherapidplanetaryrotationandmassiveplasma,howeverprecisesourceprocessesandlocationshavenotbeenclarifiedyet.
WehavereanalyzedoccurrencecharacteristicsofHOMusingtheWIND/WAVESdatatoinvestigatepreciserelationbetweenoccurrenceofnsw-HOMandJupiter'smagnetosphericvariationsobservedbytheGalileoJupiterorbiter.Asaresult,wefoundthatHOMhasthe3rdnsw-HOMcomponentappearingfrom340degto+20deginCMLwhichgenerallyappearsquasiperiodicallywiththetimescaleofafewtoseveraldaysandalsoshowslong-termoccurrencevariationswithseeminglycapricioustimescales.Acomparisonstudybetweentheoccurrencetimingofthe3rdnsw-HOMandmagnetosphericeventsfortheGalileoeraindicatesthatmostofthe3rdnsw-HOMappearedwhenmagneticreconfigurationeventsoccurredinthemagnetotailregion.Theresultsuggeststhatthe3rdnsw-HOMshallbeoneofgoodremoteproxiesindicatingoccurrenceofJupiter'sinternalglobalvariations.
Acknowledgement:TheWIND/WAVESdatawereobtainedfromtheNASAWIND/WAVESteampage.WewouldliketothankM.L.KaiserandtheWIND/WAVESteamforprovidingthedata.
72
![Page 73: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/73.jpg)
D-RingDustFallingintoSaturn’sEquatorialUpperAtmosphereMitchell,D.G.,JHU/APLPerry,M.E.,Hamilton,D.C.,Westlake,J.H.,Kollmann,P.,Smith,H.T.,Carbary,J.F.,Waite,Jr.,J.H.,Perryman,R.,Hsu,H.-W.,Wahlund,J.-E.,Morooka,M.W.,Hadid,L.Z.,Persoon,A.M.,KurthW.S.
WepresentdirectmeasurementsoftheentryofdustfromSaturn’sinnermostring(theD-ring)intoSaturn’sequatorialatmosphere.BasedonmeasurementsbytheCassinimagnetosphericimaginginstrument,measurementsthatwerenotanticipatedbefore-handandrepresentingaresponsetohypervelocitydustthatwasnotcalibrated,thedataneverthelesspresentclearevidenceforthedirectentryofnanometersizeddustgrainsasatmosphericdrag(collisionswithexospherichydrogenatoms)reducestheirorbitalvelocitiesandcausesthemtode-orbitinlessthanonerevolutionabouttheplanet.ThisrepresentsanewmechanismforthedepositionofringmaterialintoSaturn’satmosphere,uniquetotheD-ring(althoughsimilartooneproposedbyBroadfootetal.,1986atUranus).Unlikethemuchdiscussed‘ringrain’,thismechanismdoesnotinvolvedustchargingandelectromagneticinteractions(althoughthoseeffectsdoaltertheobserveddistributions),butratheradirectkineticinteractionbetweenSaturn’sexosphereanditsinnermostring.Aninterestingpredictionthatarisesfromtheanalysisofthisphenomenonisthattheinteractionshouldalsoproduceanadditional,veryhighaltitude(uptomanySaturnradii),veryanisotropic(nearequatorial)componenttoSaturn’shydrogenexosphere,aseachgrain-Hcollisionwillresultinaveryhigh-speedHatom,biasedstronglyinthedirectionofthegrainorbitalmotion.EachprecipitatinggraincanpotentiallyproducehundredsoftheseenergeticHatoms.ThismechanismmayexplainthehydrogenplumeobservedbytheCassiniUVISinstrument,asdescribedinShemanksyetal.,2009D.E.Shemansky,X.Liu,andH.Melin,Planet.SpaceSci.,57,1659(2009).A.L.Broadfootetal.ScienceVol.233,Issue4759,pp.74DOI:10.1126/science.233.4759.74(1986)ObservationsoftheJoviansodiumnebulaandIoplasmatoruswiththeIoInput/OutputFacility(IoIO)Morgenthaler,J.P.,PlanetaryScienceInstitute
TheIoplasmatorusisacollectionofionstrappedinJupiter'smagneticfieldnearIo'sorbitalradius.Basedonestimatesandmodelingoftheinterchangeinstability,theresidencetimeoftorusionsshouldbe~10hours.Theobservedresidencetimesare20--80days.Whatphysicalmechanismisimpedingradialdiffusionfromthetorus?A35cmroboticcoronagraph,theIoInput/OutputFacility(IoIO)hasbeenconstructedtohelpanswerthisquestion.IoIOhasoperatedforover130nightssinceMarch2017,recordingover2600observationsofthetorusandover700observationsoftheinnerJoviansodiumnebula.Thesodiumimagesextendtoadistanceof>80Rjandshowthedetailedstructureofthe"banana"and"stream"emissions.Theseimagescanbeusedtomeasurevariationinvolcanicactivityandconstrainmodelsoftheflowofneutralmaterialintheinnermagnetosphere.Thetorusimagescanbeusedtoestablishthetimehistoryof[SII]6731Aemissionsandvariationsinthemagnitudeofthedawn-duskelectricfield.Together,thesedataprovideachronologyofthematerialflowingintoandoutoftheplasmatorusandcanbeusedtohelpdeterminethephysicalmechanismwhichimpedesradialdiffusionfromthetorus.ThisprojectissupportedbyNSFgrantAST1616928tothePlanetaryScienceInstitute.
73
![Page 74: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/74.jpg)
Saturn’sDustyIonosphereMorooka,M.W.,IRF(SwedishInstituteofSpacePhysics),UppsalaWahlund,J.-E.
Wepresentobservationsofelectronandiondensities,thecharacteristicionmass,aswellastheelectrontemperatureobtainedbytheLangmuirProbeonboardCassiniduringtheGrandFinalorbits.Athighaltitudesabove2,500km,weidentifiedmostofthetimethattheplasmaisdominantinH+,however,someorbitsshowedanincreaseofcharacteristicionmassandelectrondensitydepletionaroundtheequator,thatindicatesthepresenceofnegativelychargeddust.Atlowaltitudesbelow2,500km,plasmadensitiesincreaserapidlyandiondensity(Ni)increasesfasterthantheelectrondensity(Ne).ThesmallNe/Niratioindicatesthepresenceofadustyplasma,aplasmathatcontainsnegativelychargedheavyparticlespredominantly.ComparisonwiththelightiondensitiesobtainedbytheIonandNeutralMassSpectrometer(INMS)indicatesthepresenceofheavyions.Apositivefloatingpotentialoftheprobehasalsobeenobservedwhentheiondensitiesareinexcessoftheelectrondensities.ElectrontemperatureenhancementshavealsofoundinthesmallNe/Niregion.TheobservationssuggestthattheplasmaofSaturn’sionosphereconsistsofbothnegativelyandpositivelychargedheavyclusterions.ObstructionofLowEnergyElectronTrajectoriestoJADE-EDuetoJupiter’sStrongMagneticFieldanditsEffectonPitchAngleMeasurementsMunoz,J.,Jr.,UniversityofTexasatSanAntonioAllegrini,F.,Valek,P.W.,Ebert,R.W.,Bagenal,F.,Kim,T.K.,Louarn,P.,McComas,D.J.,Wilson,R.J.
TheJovianAuroralDistributionExperiment-Electronsensors(JADE-E)onJunomeasureelectronsfrom0.1to100keVwithafield-of-view(FOV)of240degreesby3-5degreesthatcanbeorientedtotrackthedirectionofthemagneticfield.Intheabsenceofamagneticfield,theFOVisun-obstructed.However,inJupiter’sstrongmagneticfield,lowenergyelectronsmayhitotherspacecraftstructuresandneverreachJADE-Eduetotheirsmallgyro-radius.Preliminarystudieshaveshownthatlowenergyelectronshavingpitchanglesnear90degreesareaffectedanddonotmakeittotheinstrumentaperture.Inthisproject,wemodelelectrontrajectoriesaroundtheJunospacecrafttoquantifytheobstructiontoJADE-E’sFOVasafunctionofpitchangleandenergy.Todothis,weutilizetheionopticssoftwareSIMION8.1tosimulateelectronsflyingbackwardintimeleavingtheJADE-Esensorsoutward.Weaccountforspinphaseforeachofthe64energysteps.Iftheelectronshitastructureontheirway,thentheSIMIONsoftwareassignsthemanumberdesignatingthemtoablindspot.ThissimulationtoolrunsonesecondatatimeandcanbeusedtoevaluateFOVobstructionsaffectingflightdata.
74
![Page 75: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/75.jpg)
Juno/JIRAMobservationsofJupiter’smainauroraeandsatellitefootprints.Mura,A.,INAFAdriani,A.;Altieri,F.;Bagenal,F.;Bolton,S.;Bonfond,B.;Connerney,J.;DinelliB.M.;GérardJ-C.;Grodent,D.;Greathouse,T.K.;Levin,S.;Mauk,B.;Moriconi,M.;Plainaki,C.;Saur,J.;Waite,H.
JIRAM(JovianInfraredAuroralMapper)onboardJunoisanimager/spectrometerinthe2-5umrange.OneimagerchannelsisdesignedtostudytheJovianH3
+auroralemissions.Itshighangularresolution,combinedwiththeuniquevantagepointprovidedbyJuno,allowsJIRAMtoobservetheauroraewithunprecedenteddetails.
Herewepresenttheresultsof~2yearsofauroralobservations,withparticularemphasisontheauroralfootprintsoftheGalileanmoons.Thesearebrightspots(withassociatedtail)thatappearinJupiter’sionosphereatthebaseofthemagneticfieldlinesthatsweeppastIo,Europa,andGanymede.ThemoonsareobstaclesinthepathofJupiter’srapidlyrotatingmagnetosphericplasmaandtheresultingelectromagneticinteractionlaunchesAlfvénwavesalongthemagneticfieldtowardsJupiter,whereintenseelectronbombardmentofthehydrogenatmospherecausesittoglow.
RecentobservationsrevealforthefirsttimethatthefootprintofIoiscomprisedofaregularlyspacedarrayofemissionfeatures,extendingdownstreamoftheleadingfootprint,resemblingarepeatingpatternofswirlingvortices(vonKármánvortexstreet)shedbyacylinderinthepathofaflowingfluid.ContrarytothelargerspotsseenintheUV,thesmallscaleofthesemultiplefeatures(~100km)isincompatiblewiththesimpleparadigmofmultipleAlfvénwavereflections.Additionally,observationsofIo’strailingtailwelldownstreamofthemainfootprintrevealapairofcloselyspacedparallelarc,previouslyunresolved.
Thetemperaturesofthemainspotandtail,retrievedwiththespectrometer,arelowerthanthemainauroraloval.Thiscouldindicatethattheemissionislocatedatadeeperlevel,possiblycausedbyhigherenergyelectrons.
BothofGanymede’sfootprintspots(mainandsecondary)appearasapairofemissionfeaturesthatevidentlyprovidesaremotemeasureofGanymede’smagnetosphere,mappedfromitsdistantorbitontoJupiter’sionosphere.
75
![Page 76: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/76.jpg)
ResponseofJupiter'sinnermagnetospheretosolarwindderivedfromHisakiandJuno/JADEobservationsMurakami,G.,JapanAerospaceExplorationAgencyKita,H.,Ebert,R.W.,Kimura,T.,Tao,C.,Tsuchiya,F.,Yoshioka,K.,Yamazaki,A.,Wilson,R.J.,Valek,P.W.,Allegrini,F.,Clark,G.,Smith,T.,Suzuki,F.,Hikida,R.,Yoshikawa,I.,andFujimoto,M.
BecauseJupiter’smagnetosphereishugeandisrotationallydominated,solarwindinfluenceonitsinnerparthasbeenthoughttobenegligible.Meanwhile,dawn-duskasymmetricfeaturesofthisregionhavebeenreported.Presenceofadawn-to-duskelectricfieldisoneoftheleadingexplanationsoftheasymmetry;however,thephysicalprocessofgeneratingsuchanintenseelectricfieldstillremainsunclear.UsinglongandcontinuousmonitoringoftheextremeultravioletemissionsfromtheIoplasmatorus(IPT)inJupiter’sinnermagnetospherebytheHisakisatellitebetweenDecember2013andMarch2014,itwasrevealedthatthedusk/dawnbrightnessratiooftheIPTclearlyrespondstorapidincreasesofthesolarwinddynamicpressure.Theobservationsindicatethatdawn-to-duskelectricfieldintheinnermagnetosphereisenhancedundercompressedconditions.Inordertounderstandthephysicalprocessbetweenthesolarwindandthedawn-to-duskelectricfield,thetimescaleoftheresponseisakeyparameter.NASA’sJunospacecraftmeasuredthesolarwindduringitsapproachphasetoJupiter.WecomparedthesolarwinddynamicpressuremeasuredbyJuno/JADEandthedawn-duskasymmetryofIoplasmatorusobservedbyHisakifrom16May2016to25June2016.WefoundthreecleareventsoftheIPTresponsetosolarwinddynamicpressurevariationsandtheaverageresponsetimeis~13hours.Thistimescalecanbeanimportantconstrainttohelpidentifythephysicalmechanismofsolarwindinfluence.Long-termvariationoftheNorth–SouthasymmetryintheintensityofSaturnKilometricRadiation(SKR)in2004-2017Nakamura,Y.,DepartmentofGeophysics,GraduateSchoolofScience,TohokuUniversityKasaba,Y.,Kimura,T.,Lamy,L.,Cecconi,B.,Fischer,G.,Sasaki,A.,Tao,C.,Tsuchiya,F.,Misawa,H.,Kumamoto,A.,Morioka,A.
Thisstudyinvestigatesthelong-termvariationofSaturnKilometricRadiation(SKR)intensityobservedbytheRadioandPlasmaWaveScience(RPWS)instrumentonboardtheCassinispacecraftfrom2004(southernsummer)to2017(northernsummer).
Kimuraetal.[2013]studiedthelong-termvariationofSKRintensityinthesouthernsummerseasonfrom2004to2010andshowedthatSKRwasbrighteronthesummersidethanonthewinterside.WeextendedthisstudyuptoSeptember2017,takingadvantageofradioobservationsacquiredoverthewholeCassinimission.
Inthelong-termvariations,thetotalnorthernSKRfluxdidnotlargelychangefrom2004to2017,whilethetotalsouthernSKRfluxbecame100timessmalleratnorthernsummerthanatsouthernsummer.Astheresult,theintensityratioofsouthernSKRtonorthernSKRevolvedfrom~10aroundmidsouthernsummer(2004),reducedto~1aroundequinox(2009),andto~0.1inmidnorthernsummer(2015).Theseresultsshowthat(1)SKRisbrighterinthesummerhemisphere,inagreementwithKimuraetal.[2013],(2)thereversalintheintensityratiowasmainlycausedbythelong-termreductionofthesouthernSKRintensity,and(3)thelong-termvariationoftheintensityratiowasnotclearlysynchronizedtothatofnorthernandsouthernSKRrotationalperiods.WedidnotfindacorrelationbetweentheSKRintensitiesandthesolarEUVflux.WethusconcludethattheseasonalvariationofsolarEUVilluminationofSaturn’sionospheredonotsimplycausetheSKRintensityvariations.
76
![Page 77: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/77.jpg)
StudyoftheJovianmagnetosphere-ionospherecouplingusinganionosphericpotentialsolver:ContributionsofH+andmeteoricionstoionosphericconductivityNakamura,Y.,DepartmentofGeophysics,GraduateSchoolofScience,TohokuUniversityTerada,K.,Tao,C.,Terada,N.,Kasaba,Y.,Kita,H.,Nakamizo,A.,Yoshikawa,A.,Ohtani,S.,Tsuchiya,F.,Kagitani,M.,Sakanoi,T.,Murakami,Go.,Yoshioka,K.,Kimura,T.,Yamazaki,A.,Yoshikawa,I.
ThecorotationofJovianmagnetosphericplasmadominatestheconvectionintheJovianinnermagnetosphere.Therefore,thesolarwindhardlyinfluencestheplasmaconvectionthere.However,theHisakisatelliteshowedthatthebrightnessintensityoftheIoplasmatorus(IPT)changedasymmetricallybetweenthedawnandthedusksidesandthischangecoincidedwitharapidincreaseinthesolarwinddynamicpressure.Suchchangecanbeexplainedbytheexistenceofadawn-to-duskelectricfieldof~4-9mV/maroundIo’sorbit.Thedawn-to-duskelectricfieldshiftsthepositionofIPTtowarddawnsideby~0.1-0.3RJandtheplasmaintheIPTisadiabaticallyheatedatduskandcooledatdawn,whichmakesthedawn-duskbrightnessasymmetry.Thefollowingprocesseshavebeensuggestedasapossiblecauseofthedawn-to-duskelectricfield.First,theJovianmagnetosphereiscompressedbyanincreaseinthesolarwinddynamicpressure.Then,theM-Icurrentsystemismodified,andtheFACconnectedtothehigh-latitudeionosphereincreases.Asaresult,theionosphericelectricpotentialincreasesandpenetratestolowerlatitudes.Itismappedtotheequatorialplaneoftheinnermagnetospherealongmagneticfieldlines,andthedawn-to-duskelectricfieldiscreatedaroundIo’sorbit.
Inordertodemonstratethisscenarioquantitatively,weconstructeda2-Dionosphericpotentialsolver,whichwascomposedofaphotochemicalmodel,aheight-integratedconductivitymodel,andaPoissonequationsolver.Wecalculatedtheionosphericpotentialandtheresultingdawn-to-duskelectricfieldatIo’sorbitusingFACsestimatedfromGalileoobservations.Thecalculateddawn-to-duskelectricfieldmarginallyagreedwiththeHisakiobservationsonlywhenweaddedH+andmeteoricionstoourphotochemicalmodel.OurresultssuggestthattheH+andmeteoricionsplayamajorroleindeterminingtheionosphericconductivityandtheelectricfieldintheJovianinnermagnetosphere.
77
![Page 78: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/78.jpg)
WhathasbeenlearntabouttheradiationbeltsofJupiterwiththephysicalmodelSalammbôNenon,Q.,ONERASicard,A.Kollmann,P.Garrett,H.B.
Thedistributioninkineticenergy,latitudeandradialdistanceofthehigh-energyparticlefluxesencounteredintheradiationbeltsofJupiterisdrivenbythevariousphysicalprocessesactingonthetrappedparticles.Eventhoughthesebeltshavebeenobservedremotelysince1959andin-situsince1973,disentanglingthephysicalmechanismsattheoriginoftheobservedfluxesonlyfromtheobservationsremainsdifficult,sothatamodelingeffortisneeded.Forinstance,whatdoesremove99%ofMeVprotonsnearIo’sorbit,asobservedbyPioneer10-11,Voyager1,GalileoandJuno?Isitanabsorptioneffectofthevolcanicmoon,chargeexchangewithitsneutraltorus,Coulombcollisionswiththeplasmatorusorpitch-anglescatteringbyEMICwaves?
Ononehand,in-situobservationsarecarefullyselectedanddiscussedinthispresentation.Forinstance,GalileoProbeprotonmeasurementsfrom1.8Rjto2.3RjfromthecenterofJupiterarenotanevidenceforaprotonsourcenearthegiantplanet(CRAND)butarecontaminatedbyheavyions.
Ontheotherhand,allthephysicalprocessesabletoshapetheradiationbeltsaremodeledintheglobalphysics-basedmodelnamedSalammbô,developedsince1998atONERAandrecentlyrevisited.
ThispresentationwillshowhowthecomparisonbetweenthefluxespredictedbytheSalammbômodelandtheobservationsenablestodeterminethedominantmechanismsatworkintheradiationbelts.
Themainresultsofourstudywillbediscussed.Inparticular,wewillpointoutthatpitch-anglescatteringbyEMICwavesobservedbyGalileo-MAGandHiss-likewavesobservedbyGalileo-PWSseverelylimitstheintensityofMeVprotonsandelectronsnearIo’sorbit.Ifwave-particleinteractionwasnotefficientinthemagnetodisc,theinnermostradiationbeltsofJupiterwouldbe20to50timesharsherthanwhatisobserved.ConstrainingPlasmaConditionsoftheIPTviaSpectralAnalysisofUV&VisibleEmissionsandComparingwithaPhysicalChemistryModelNerney,E.G.,LASP,UniversityofColorado,BoulderBagenal,F.
Ioemitsvolcanicgasesintospaceatarateofaboutatonpersecond.ThegasesbecomeionizedandtrappedinJupiter’sstrongmagneticfield,formingatorusofplasmathatemits2terawattsofUVemissions.Inrecentworkre-analyzingUVemissionsobservedbyVoyager,Galileo,&Cassini,wefoundplasmaconditionsconsistentwithaphysicalchemistrymodelwithaneutralsourceofdissociatedsulfurdioxidefromIo(Nerneyetal.,2017).InfurtheranalysisofUVobservationsfromJAXA’sHisakimission(usingourspectralemissionmodel)weconstrainthetoruscompositionwithgroundbasedobservations.Thephysicalchemistrymodel(adaptedfromDelamereetal.,2005)isthenusedtomatchderivedplasmaconditions.Wecorrelatetheoxygentosulfurratiooftheneutralsourcewithvolcaniceruptionstounderstandthechangeinmagnetosphericplasmaconditions.OurgoalistobetterunderstandandconstrainboththetemporalandspatialvariabilityoftheflowofmassandenergyfromIo’svolcanicatmospheretoJupiter’sdynamicmagnetosphere.
78
![Page 79: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/79.jpg)
TransportandTurbulentHeatinginSaturn’sMagnetosphere.Neupane,Bishwa,UniversityofAlaskaFairbanksPeterDelamere,BrandonBurkholder,C.-S.Ng
Saturn'smagnetodiscisrapidlyrotatingwithaninternalplasmasource.Radialtransportoccursbyacentrifugally-driveninterchangeinstability,determinedbyradialgradientoffluxtubecontentandfluxtubeentropy.Plasmaproducedintheinnermagnetospheremustbetransportedradiallyoutward.Theoutwardmotionoftheplasmastretchesthemagneticfieldlines,leadingtoamagnetodiscconfiguration.Reconnectionallowsmagneticfluxtocirculatebacktotheinnermagnetosphere.Saturn'smagnetodisccanbecategorizedasactiveorquiet.Theactiveperiodisdefinedwherewehavesignificantvariationinallthreecomponentsofmagneticfield(andwhereweseeanumberofcurrentsheetcrossings).However,inthequietperiod,theexpectedstructureofthemagnetodiscispresent(i.e.positiveBθwithradialandazimuthalcomponentspresentbutnocurrentsheetcrossings).Wehavefoundthatroughly1%ofthetimethemagnetodisccanbecategorizedas"active".Duringtheactiveperiod,itissuggestedthatturbulenceisthesourceofplasmaheating.Therequiredheatingratedensity(BagenalandDelamere,2011)ofthewholemagnetosphereiscomparablewiththeheatingintheactiveregions.Wehaveobservedactiveeventsnotonlyattheequatorialplanebutalsoathigherlatitude(greaterthan10degree).Thedwelltimenormalizationofactiveeventshowsthatmostoftheeventshappenbetween10degreeto20degreelatitude.Wewilldiscussthespotheatingandtransportassociatedwiththeactiveregionsofthemagnetosphere.Goings-oninJupiter'sauroras:PeriodicemissionwithinJupiter’smainauroralovalandshorttimescalevariationsinthemotionoftheGanymedefootprintNichols,J.D.,UniversityofLeicesterBonfond,B.,Bunce,E.J.,Chowdhury,M.N.,Cowley,S.W.H.,Robinson,T.R.,Yeoman,T.K.
InthispresentationwediscusssomeresultsfromaprogrammeofHubbleSpaceTelescopeobservationsofJupiter’sFUVaurorasobtainedduring2016.Inparticular,wehavediscoveredpulsatingemissionwithinJupiter’smainauroraloval,providingevidenceoftheauroralsignatureofJovianULFwaveprocesses.Theformcomprisesa1O×2Ospotlocateddirectlyonthemainemission,whoseintensityoscillateswithaperiodof~10minthroughoutthe45minobservation.Thefeatureappearsontheduskwardedgeofthediscontinuity,mapsto~13–14hLTand~20–50RJ,androtatesataroundahalfofrigidcorotation.WeshowthattheperiodoftheoscillationissimilartotheexpectedAlfvéntraveltimebetweentheionosphereandtheupperedgeoftheequatorialplasmasheetinthemiddlemagnetosphere,andwethussuggestthatthepulsatingauroraisdrivenbyamodeconfinedtothelow-densityregionoutsidetheplasmasheet.Wealsodiscussthediscoveryofshort(10min)timescalevariationsinthelocationoftheGanymedeauroralfootprint,whichpossiblyindicatechangesintheambientplasmadensitynearGanymede.
79
![Page 80: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/80.jpg)
Theatmosphericconsequencesofmid-latitudemagnetosphere-ionospherecouplingatSaturnO'Donoghue,James,NASAGoddardSpaceFlightCenterMoore,L.,Connerney,J.E.P.,Melin,H.,Stallard,T.,Miller,S.,Baines,K.H.
Weperformedanewanalysisofground-basedobservationsthatweretakenon17April2011usingthe10-metreKecktelescopeonMaunaKea,Hawaii.H3
+emissionswerepreviouslyanalyzedfromtheseobservations,indicatingthatpeaksinemissionatspecificlatitudeswereduetoaninfluxofchargedwaterproductsfromtheringsknownas'ringrain'.SubsequentmodelingshowedthatthesepeaksinemissionarelikelydrivenbyanincreaseinH3
+density,ratherthantemperature,asalocalreductioninelectrondensity(duetochargeexchangewithwater)lengthensthelifetimeofH3
+.However,missinguntilnowwasadirectderivationoftheH3
+parameterstemperature,densityandradiance,whicharerequiredtoconfirmandexpandonexistingmodelsandtheory.HerewepresentmeasurementsoftheseH3
+parametersforthefirsttimeinthenon-auroralregionsofSaturn.Weconfirmthatindeed,H3
+densityisenhancedneartheexpected'ringrain'planetocentriclatitudesof45Nand39S.Inaddition,theH3
+densityisremarkablyhighat39S,likelyduetothesouthward-inclinedmagneticfieldinthevicinityoftheringplane,whichleadstochargedgrainsbeingimmediatelydrawnsouthwardsduetogravitationalforcesinthatregion.Ananti-correlationbetweenH3
+temperatureanddensitywasalsoobservedat39S,potentiallyindicatingthatmostchangetotheionosphereduetoringrainisinthedeepionosphere.Finally,Saturn'sicymoonEnceladusappearstobrightenH3
+at61S,perhapsduetoawaterinfluxbutwithanunknowntransportmechanism.AuroralstormandpolararcsatSaturn–FinalCassini/UVISauroralobservationsPalmaerts,B.,LPAP,UniversityofLiegeRadioti,A.,Grodent,D.,Yao,Z.H.,Bradley,T.J.,Roussos,E.,Lamy,L.,Bunce,E.J.,Cowley,S.W.H.,Krupp,N.,Kurth,W.S.,Gérard,J.-C.andPryor,W.R.
On15September2017theCassinispacecraftplungedintoSaturn'satmosphereafter13yearsofsuccessfulexplorationoftheSaturniansystem.Thedaybefore,theUltravioletImagingSpectrograph(UVIS)onboardCassiniobservedSaturn'snorthernauroraforabout14h.InthisfinalUVISsequence,severalauroralstructuresappear,revealingprocessesoccurringsimultaneouslyinSaturn'smagnetosphere.Apolewardexpansionandabrighteningofthemainemissiondawnarc,aphenomenonknownasanauroralstorm,suggeststhatanintensefluxclosureprocesstookplaceinthemagnetotailthroughmagneticreconnection.Thismagnetotailreconnectionandtheassociatedfielddipolarizationgeneratedsignaturesintheauroral,magneticfield,andplasmawavedata.TheenhancedmagnetotailreconnectionislikelycausedbyacompressionofthemagnetosphereinducedbythearrivalatSaturnofaninterplanetarycoronalmassejection.Inadditiontotheauroralstorm,apolararcobservedonthedusksidewastrackedforthefirsttimefromthestartofitsgrowthphaseuntilitsquasidisappearance,providingevidenceofitsformationprocess.Thispolararcisaproxyforthelocationofreconnectionsitesonthedaysidemagnetosphereandfortheorientationoftheinterplanetarymagneticfield.Finally,theatypicalobservationofoneofthemostpolarauroralarcseverreportedatSaturnsupportsthescenarioofaninterplanetaryshockarrivingatSaturnattheendoftheCassinimission.Inthatrespect,theultimateUVISauroralsequenceallowedustocapturedynamicalaspectsofSaturn’smagnetospherenotfrequentlyorevenneverobservedinthepast.
80
![Page 81: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/81.jpg)
OpenandpartiallyclosedmodelsofsolarwindinteractionwithSaturn'smagnetosphereParunakian,D.A.,MoscowStateUniversityBelenkayaE.S.,CowleyS.W.H.,AlexeevI.I.,KalegaevV.V.,PensionerovI.A.,BlokhinaM.S.
InthisworkweexaminetheissueofreconnectionefficiencyinSaturn'smagnetosphereforcasesofnorthwardandsouthwardIMFusingtheparaboloidmagnetospheremodelfittedtodataacquiredbytheCassinimagnetometer,andimagesofSaturn'sUVauroraacquiredbytheHST.
ThereconnectionefficiencyisinvolvedinacomplexinterplayofvariousimportantfactorsaffectingtheinteractionofthesolarwindandSaturn'smagnetosphere,butcurrentlyaclearunderstandingofthispictureislacking.Themagnetosheathpropertiesareconnectedwiththereconnectionrate.FromaverylowreconnectionefficiencyazerodegreeofIMFpermeabilityintothemagnetospherewouldfollow.
Wecomparetheopen-closedboundarylayoutandfieldlinestructureoftwomodelvariants:anopenmodelwithapenetratingIMF,andapartiallyclosedmodelinwhichfieldlinesfromtheionosphereextendtothedistanttailandinteractwiththesolarwindatitsremoteend.WeshowthattheresultsproducedbytheopenmodelmatchHSTauroraobservationsbetter.ThemagnetosphericinteractionbetweenNeptuneandTritonPaty,C.,GeorgiaTech/UniversityofOregonCao,X.
Tritonprovidesanexcitingicymoon-magnetosphereinteraction,andonethathasyettobeexploredbyinsituspacecraftotherthanfromadistanceof~40,000kmbyVoyager2.TheobservationsfromthatbriefencounterrevealedTritontobeaninterestingtargetoffuturestudy;ahigh-densityicymoonwithactivegeysersofnitrogengasanddarkparticles,adiffuseatmosphere,andaretrogradeorbitindicativeoforiginsbeyondNeptune.Thegeologyrevealsahistoryofresurfacingandthepotentialfortidalheatingprocessesinthesubsurface,likelytheresultofTriton’scaptureandorbitalevolution.InthisposterweexaminethenatureofTriton’sinteractionwithNeptune’smagnetosphere,includingthevariablemagneticenvironmentexperiencedduringTriton’s5.88-dayorbitwhichmayprovideadriverforaninducedmagneticfield.OurstudywillincludeasuiteofsimulationsofTriton’snearspaceenvironmentbasedonthesimpleassumptionsofthepresence(orlack)ofasubsurfaceoceancapableofsustaininganinducedmagneticfield.
81
![Page 82: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/82.jpg)
Relativefractionsofwater-groupionsinSaturn’sinnermagnetospherePerry,M.E.,JohnsHopkinsApplitedPhysicsLabCravens,T.E.,Tokar,R.,Smith,H.T.,Waite,J.H.Jr.,McNutt,R.L.Jr.
Attwodozentimesovertenyears,theCassiniIonNeutralMassSpectrometer(INMS)measuredtherelativefractionsofwater-groupionsintheinnermagnetosphereofSaturnneartheequatorialplanebetween3.8and6.5Saturnradii(Rs).Unlikeenergy-sortinginstruments,eachINMSmeasurementdeterminestheabundanceofasingleion,withnoambiguityinidentifyingtheparticularionwithinthewatergroup.EachINMSmeasurementcoversasmallportionofvelocityspace,sovelocity-dependentfractionsarepossibleifthemultipledependentparametersandtemporalvariationscanbede-convolved.Densitiesandcountratesarelow,sometimesrequiringbinning10,000countstoachievea2-sigmaresult.Takentogether,INMSionmeasurementsspannedabroadrangeofvelocityspace,fromthecoreofthedistributiontomultiplesofthepick-upvelocity.
ThedatashowthatH2O+comprisesthebulkoftheionsnear4.0Rs,andthattheH2O+fractiondecreaseswithincreasingdistancefrom4.0Rs,thesourceofneutralwateratEnceladus.At4.0Rs,thefractionofH2O+rangesfrom60%to100%,withthewater-groupionsthatareclosesttothepick-upvelocityhavingthehighestfractionofH2O+.At6.5Rs,thethreemainwater-groupconstituents,H2O+,OH+,andO+,arenearlyequal.H3O+,whichdominatesthewater-groupionfractionsintheEnceladusplume,is10%orlessinSaturn’smagnetosphereoutsidetheplume.Othervariationsintherelativeionfractionsdonotshowclearlinkstoparameterssuchasvelocity,density,andtheorbitphaseofEnceladus.IoplasmatorusgeometryfromJunoradiooccultationsPhipps,P.H.,DepartmentofAstronomy,BostonUniversityWithers,P.,Buccino,D.R.,Yang,Y.-M.,Hinton,P.C.,Bagenal,F.
Io’svolcanicactivity,thedominantsourceofplasmaatJupiter,releasesmaterialintoIo’satmospherewhichislosttoJupiter’smagnetospherenearIo.ThismaterialisthenionizedandtrappedbythemagneticfieldtoformatorusofplasmaaroundJupiter,calledtheIoplasmatorus.Thisplasmacanbedetectedbyradiooccultationsinwhichtheplasma’stotalelectroncontentaffectspropertiesofaspacecraft’sradiosignalasitpropagatesthroughtheplasmaonthewaytothereceiver.ThetotalelectroncontentoftheIoplasmatorusisderivedfromthedualfrequency(KaandX-band)gravitymeasurementsfromtheJunospacecraftduringPerijove1.Thetimeforthepeakofthedistributionisfoundtobedeterminedbythelocationofthecentrifugalequatorialplane.Wepresenttheeffectofdifferentfieldlinemodelsonthetotalelectroncontentprofiles.Preliminaryresultsfromsubsequentperijovesarealsopresented.
82
![Page 83: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/83.jpg)
ElectrostaticsolitarywavesobservedduringCassini'sring-grazingandGrandFinaleorbitsPíša,D.,IAPCAS,Prague,CzechiaPickett,J.S.,Sulaiman,A.H.,Souček,J.,Ye,S.-Y.,Kurth,W.S.,Gurnett,D.A.,Santolík,O.
AttheendofNovember2016,Cassinistartedasetof20highlyinclinedring-grazingorbitstoexploreregionattheouteredgeofSaturn’smainrings.StartinginApril2017,thespacecraftmade22highlyinclinedorbitsatunprecedentedproximitytotheplanet.ThesephasesofCassini'smissionofferedanewinsightintounexploredterritoryofSaturnandtheplanet'sconnectionwithitsringsystem.TheWidebandReceiver(WBR),apartoftheRadioandPlasmaWaveScienceinstrument,oftendetectedstrikingmono-,bi-ortri-polarstructuresinwaveformsnapshots.Thesestructurescanbetheresultofelectrostaticsolitarywaves(ESWs)ordustimpacts.Forproperidentification,eventshavetobeoftenvisuallyinspected.TypicalexamplesofESWsanddustimpactsareprovidedtoshowtheirpropertiesanddifferences.UsingalmostfivemillionWBRwaveformsnapshots,wecarryoutasurveyofbipolarelectrostaticsolitarywavesdetectedduringthelastphasesofCassini'smissionatSaturn.Wediscusstheirpropertiesandpossiblegenerationprocesses.
RotationoftheInterplanetaryMagneticFieldinSaturn'sMagnetosheathPonce,I.D.,OglethorpeUniversityMeier,M.J.
ThemagnetospheresofJupiterandSaturnbothcontainplasmasheetsduetointernalsourcesofplasma,primarilyIoatJupiterandEnceladusatSaturn.Theeffectoftheseplasmasheetsonthemagnetopauseboundaryistoinflatethemagnetopauseintheequatorialregion,withtheresultthatthemagnetopauseisnotaxisymmetric,asshownintheoreticalmodeling(EngleandBeard,JGR85,1980;Staharaetal,JGR94,1989)anddata(Slavinetal,JGR90,1985).Theasymmetryofthemagnetopauseboundaryissensitivetothesolarwinddynamicpressure(Joyetal,JGR107,2002;Arridgeetal,JGR111,2006),withhigherdynamicpressurecorrespondingtoagreaterdegreeofasymmetry.
MHDsimulationsofsolarwindflowaroundanonaxisymmetricboundaryhaveshownthattheinterplanetarymagneticfieldisexpectedtorotateasthesolarwindapproachestheboundary(Erkaevetal,JGR101,1996;Farrugiaetal,Planet.Space.Sci.46,1998).Themagnetosheathmagneticfieldattheseplanetsisthereforeexpectedtobeorientedclosetoperpendicularwiththeequatorialplanenearthesubsolarpointandintheequatorialregionalongtheflanks,leadingtoconditionsthatarefavorableforthedevelopmentoftheKelvin-Helmholtzinstability(Desrocheetal.,JGR118,2013;Desrocheetal.,JGR117,2012).
AninitialstudyofthemagneticfieldrotationinJupiter’smagnetosheath(Ponce&Meier,AGUFallMeeting2017)wasunabletofindaconsistentsignatureofthepredictedmagneticfieldrotation.Inthepreviousstudy,twocrossingsoftheJovianmagnetosheathwereanalyzed–onefromPioneer10andtheotherfromUlysses.Inthisstudy,weextendthepreviousworktolookforrotationofthemagneticfieldinSaturn’smagnetosheath,usingtheCassinimagnetometerdata.
83
![Page 84: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/84.jpg)
Consequencesofnon-conformalmagneticfieldmappingPontius,D.H.,Birmingham-SouthernCollegeFernanzez,C.,Brooks,E.L.
Analytictreatmentsofmagnetospheric-ionosphericcouplingtypicallyassumethattheplanetarymagneticfieldisnorth-southsymmetric.Thatimpliesthattheionosphericfootprintsofanymagneticfluxtubeareidenticalinthetwohemispheres.Forconstantionosphericconductivityandperfectlyconductingmagneticfieldlines,whenfield-alignedelectriccurrentsfromtheplasmasheetareinjectedintotheionospheresalongtheboundaryofafluxtube,thecurrentscancloseentirelywithineachhemisphere.However,inarealisticrepresentationofafieldsuchasJupiter's,themappingisnon-conformalandLaplace'sequationcannotbesatisfiedsimultaneouslyinbothhemispheres.Wetreatasimplesituationwhereafluxtubeofsmallcrosssectionismappednon-conformallybetweentheionospheres.Twosituationsareconsidered:(i)onefootprintisstretchedoutalongoneaxisandcompressedalongtheother,withtheoppositemappingintheotherhemisphere,and(ii)thefootprintsexperiencecomplementarynon-orthogonalmappings.Inadditiontothecurrentsontheedgeofthefluxtube,therearenowcurrentsonfieldlinesoutsidethefluxtubethatpassentirelyfromonehemispheretotheother.Dependingonthedegreeofdistortion,thetotalmagnitudeofthoseauxiliarycurrentscanbecomparabletotheoriginalfluxtubecurrent.ThermalandenergeticiondynamicsinGanymede'smagnetospherePoppe,A.R.,SpaceSciencesLab.,U.C.BerkeleyFatemi,S.;Khurana,K.K.
Ganymedeisthesolarsystem'sonlyknownmoonwithanintrinsic,globalmagneticfield.Thisfieldisstrongenoughtostandofftheincidentjovianmagnetosphericflowandformsasmall,yetcomplexmagnetospherearoundthesatellite.Ganymede'smagnetosphereisthoughttoberesponsibleforvariablesurfaceweatheringpatterns,theproductionofaneutralexosphere,andthegenerationofUVauroraenearGanymede'sopen-closedfieldlineboundaries;however,theexactdetailsandunderlyingmechanismsarenotfullyunderstood.Here,weuseresultsfrompreviousthree-dimensionalhybridmodelsofGanymede'smagnetosphereandathree-dimensionalparticle-tracingmodeltoquantifythedynamicsofthermalandenergeticjovianionsastheyinteractwithGanymede'smagnetosphereandprecipitatetothesurface.Weidentifytheformationofquasi-trappedionicradiationbeltsinthemodel,similartothatobservedbytheGalileoEnergeticParticleDetector,andvariablesurfaceweathering,correspondingtoVoyagerandGalileoobservationsoftheganymedeansurface.WefindthatmostoftheparticleprecipitationoccursinGanymede'spolarcaps,yetenergeticionscanalsoprecipitatetoGanymede'sequatorialregioninsomewhatlesseramountsthaninthepolarregionsduetoparticleshadowingofquasi-trappedionsinGanymede'sionicradiationbelts.ModelresultspredictthatforconditionswithinJupiter'scentralplasmasheet,totalionfluxestoGanymede'spolar,leading,andtrailinghemispheresare50e6cm-2s-1,10e6cm-2s-1,and0.06e6cm-2s-1,respectively.Finally,convolutionofincidentionfluxeswithexperimentallymeasuredneutralsputteringyieldsforicybodiespredictsneutralsputteredfluxesinGanymede'spolar,leading,andtrailinghemispheresof1.3e9,4.8e8,and1.2e8neutralscm-2s-1,respectively.
84
![Page 85: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/85.jpg)
Saturn’snorthernauroraeatsolsticefromHSTobservationscoordinatedwithCassini’sGrandFinalePrangé,Renée,LESIA,ObservatoiredeParisL.Lamy,C.Tao,T.Kim,S.Badman,P.Zarka,B.Cecconi,W.S.Kurth,W.Pryor,E.BunceandA.Radioti,
Saturn'snorthernfar-ultravioletauroraehavebeenregularlyobservedthroughout2017withtheSpaceTelescopeImagingSpectrograph(STIS)oftheHubbleSpaceTelescope(HST),duringnorthernsummersolstice.TheseconditionsprovidedthebestachievableviewingofthenorthernkronianauroralregionforanEarth-basedtelescopeandamaximalsolarillumination,expectedtomaximizethemagnetosphere-ionospherecoupling.TheHSTobservationswerecoordinatedwithinsitumeasurementsalongthepathoftheCassinispacecraftacrossauroralfieldlinesduringtheGrandFinale.Inthisstudy,weanalyze24STISimagesconcurrentlywithquasi-continuousCassini/RPWSmeasurementsofSaturn'sKilometricRadiationandsolarwindparametersderivedfromnumericalMHDmodels.Theobservednorthernauroraedisplayhighlyvariableauroralcomponents,withatotalpowerrangingfrom7to124GW.Theyincludeaprominentmainovalabove72°latitudeswhichbearsclearsignaturesofthesolarwindandplanetaryrotationcontrol,frequentcuspemissionsnearnoon,withanunusuallybrighteventwhichradiated13GW,andadaysideweaksecondaryovalaround70°latitude.Inaverage,thenorthernauroraedisplayastrongLTdependencewithtwomaximaatdawnandpre-midnight,thelatterbeingattributedtoregularnightsideinjectionspossiblyassociatedwithsolsticeconditions,butnoobviousrotationaldynamics.TheseresultsprovideareferencebasistoanalyzeCassiniinsituand/orremotemeasurements,whethersimultaneousornot.WillweeverknowthetimeonSaturn?Saturn’sPlanetaryPeriodOscillationsobservedthroughouttheCassinimission.Provan,G,UniversityofLeicesterCowley,S.W.H.,Bradley,T.J.,Bunce,E.J.,Hunt,G.J.,Lamy,L.,Dougherty,M.K.
WereportonaseriesofstudiesdeterminingpropertiesofSaturn’splanetaryperiodoscillations(PPOs)fromCassinimagneticmeasurementsthroughouttheCassinimission,beginningunderpost-solsticesouthernsummerconditionsin2004,extendingthroughvernalequinox,andfinishingafternorthernsummersolsticeatendofmission.WediscusstheseasonalevolutionofPPObehavior,comparingourresultswiththosederivedfromanalysisofSaturnkilometricradiationemissionsfromtheVoyager,Ulysses,andCassinimissions.Thephasesderivedfromthemagneticdataprovideasuitableframeworkwithinwhichtoorganizeothermission-longmagnetosphericdata,andarefreelyavailabletothecommunity.
WefurtherpayparticularattentiontoPPOobservationsontheCassiniFringandproximalorbits,whichallowuniquehigh-cadencemeasurementsofthephaseandamplitudeofthePPOsneartheopen-closedfieldboundaryinthenear-midnightmagnetictail.Thesedatanewlyrevealthepresenceofdualmodulatedoscillationsvaryingatthe~42daybeatperiodofthenorthernandsouthernsystemsonthesepolarfieldlines.WediscussapossibletheoreticalscenariowherebyPPOsinonehemispherearecommunicatedviafieldalignedcurrentsonclosedfieldlinestotheoppositehemisphere,wheretheydrivevorticalflowswhichextendontopolaropenfieldlines.Theproximalorbitsalsonewlyprovideaccesstofieldregionsthreadingthroughandinsidetheplanetaryringsystem.Wedescribeinitialanalysesofthefielddataonsuchfieldlines,andshowthatPPOoscillationsareingeneralpresentthroughouttheseregions.
85
![Page 86: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/86.jpg)
CassiniUVISObservationsofSaturn'sAurorasandPolarHazePryor,W.R.,CentralArizonaCollegeEsposito,L.W.,West,R.A.,Jouchoux,A.,Grodent,D.,Gerard,J.-C.,Gustin,J.,Radioti,A.,Lamy,L.,Koskinen,T.
In2016and2017,theCassiniSaturnOrbiterexecutedafinalseriesofhighinclination,low-periapsisorbitsidealforstudyingSaturn'spolarregions.TheCassiniUltravioletImagingSpectrograph(UVIS)obtainedanextensivesetofauroralimagesofbothpoles,someatthehighestspatialresolutionobtainedduringCassini'slongorbitalmission(2004-2017).Insomecases,twoorthreespacecraftslewsatrightanglestothelongslitofthespectrographwererequiredtocovertheentireauroralregiontoformimagesofauroralH2andHemission.
ThelongwavelengthpartofthenorthernUVISpolarimagescontainsasignalfromreflectedsunlightwithabsorptionsignaturesofacetyleneandotherSaturnhydrocarbons.Saturn'sUV-darkpolarhexagonisnowseeninthenewUVISlong-wavelengthdata,surroundedbyacircularcollarthatislessdark.ThereisadefinitespatialrelationshipbetweentheUV-brightaurorasandthedarkmaterial,withthedarkmaterialconcentratedunderorjustinsideofthemainauroraloval.Theouterdarkcollarroughlycorrespondswiththepreviouslyreportedweakerouterauroraloval(Grodentetal.,2011;Lamyetal.,2013).Timevariationsinthedarkmaterialareseen.Thespectroscopyofthedifferentregionswillbediscussed.AshasbeenpreviouslydiscussedusingVoyagerdata(Laneetal.,1982,Westetal.,1983,PryorandHord,1991),Hubbledata(BenJaffeletal.,1995;Gerardetal.,1995)andCassinidata(Sayanagietal.,2018),Saturn'saurorasappeartobegenerating,throughbothneutralandionchemistry,UV-darkmaterialthatisprobablycomposedofcomplexhydrocarbons.PropertiesofJupiter'sDawnMagnetosheathasMeasuredbyJunoandNewEstimateofthePolarFlatteningofJupiter'sMagnetosphereRanquist,D.A.,UniversityofColorado-Boulder(LASP)Bagenal,F.,Wilson,R.J.,Hospodarsky,G.B.,Valek,P.W.,Connerney,J.E.P.,Kurth,W.S.
Juno's53-dayorbit,withitsapojoveat112RJ,hasspentasubstantialamountoftimeinthemagnetosheathonthedawnsideofJupiterandcrossedthemagnetopauseboundarymorethanahundredtimes.JunofirstenteredthemagnetosheathonJune24,2016andthelastrecordedmagnetosheathcrossingoccurredonJanuary6,2018.ItisincreasinglyunlikelythatJunowillre-enterthemagnetosheathuntilafterorbit30(November2020).UsingtheJovianAuroralDistributionsExperiment(JADE),theMagneticFieldInvestigation(MAG)andtheWavesInvestigation(Waves),wepresentthestatisticalplasmapropertiesofJupiter'sdawnmagnetosheath,includingmagneticfieldstrengthanddirections,densities,plasmaflowvelocities,pressures,Alfvénspeeds,andplasmabetas.CharacterizingJupiter'smagnetosheathpropertiesisimportanttounderstandthefrequencyandefficienciesofmagneticreconnectionandtheKelvin-Helmholtzinstabilityatthemagnetopauseboundary.Inaddition,wepresentanewmethodofusingthedrapingofthemagneticfieldinthemagnetosheathtoestimatethepolarflatteningofJupiter'smagnetosphere.
86
![Page 87: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/87.jpg)
IoVolcanoMonitoringfromtheIRTFinSupportofJunoandHisakiRathbun,J.A.,PlanetaryScienceInstituteSpencer,John.R.
Sinceearly2016wehaveimagedIo's2.2-4.8micronvolcanicthermalemissiononnearly80dates,inparttoprovideconstraintsonIo'svolcanicinputtoJupiter'smagnetosphereinsupportoftheJunoandHisakimissions.WehaveusedtheNASAIRTF,andtheguidecamerasfortheSPEXandISHELLspectrographs,forthiswork.WeimageIoinsunlight,Jupitereclipse,andduringJupiteroccultations,constraininglocationsandbrightnessesofvolcanosbothviadirectimagingandJupiteroccultationtiming.DuringthisperiodwehaveobservedoneoftheLokivolcano'sremarkableperiodicbrightenings,fromFebruary-July2016.WehavenotobservedanymajoroutburstsanywhereonIo,thoughgapsintemporallongitudecoveragedonotruleouttheoccurenceofshort-livedoutburstsduringthisperiod.CharacterisingJupiter'sAuroralAccelerationRegionRay,L.C.,LancasterUniversityArridge,C.S.
AtJupiterandothermagnetizedplanets,auroralemissionsaresignaturesofparticleaccelerationabovetheplanetaryatmosphere.PriortothearrivalofJuno,itwasexpectedthatquasi-staticfield-alignedpotentialswoulddominateJupiter’sauroralaccelerationregion(AAR),similartothoseatEarth.Surprisingly,insitudatasuggeststhatstochasticaccelerationismorewidelypresentinJupiter’sAAR.WeusetwomethodstodescribeparticleaccelerationatJupiter.Inthefirst,weconsiderquasi-staticfieldalignedpotentials,usingHSTimagesofJupiter’sauroracombinedwiththeKnightRelationandBayesiananalysistoinferthecharacteristicsofJupiter’sauroralaccelerationregioni.e.initialenergyanddensityofprecipitatingelectrons,andthelocationofaccelerationregion.ThesecondmethodconsiderstheaccelerationoftrappedelectronsbykineticAlfvénwavestopredicttheprecipitatingauroralenergyfluxes.WecomparetheinferredAARpropertiesfrombotheventstoJunomeasurements.
87
![Page 88: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/88.jpg)
HSTMid-Cycle25EuropaCampaigns:NewApproachestoConstrainPlumeAbundance,Composition,andVariabilityRetherford,K.D.,SouthwestResearchInstituteL.Roth,J.Saur,D.F.Strobel,P.D.Feldman,N.Ivchenko,T.M.Becker,D.C.Grodent,L.Paganini,A.Bloecker,M.Ackland,P.M.Molyneux,K.R.deKleer
WereportearlyresultfromourlatestsetofEuropaplumesearchingobservationsobtainedaspartofHubble’sMid-Cycle25EuropaCampaigns.Wehaveplannedasetof55orbitswith22visitsduringtheJupiterobservingseasonstartingonMarch28,2018andspreadintoJuly.InadditiontocontinuedSpaceTelescopeImagingSpectrograph(STIS)instrumentlong-slitfar-UVauroralLyman-alphaandoxygenlineemissionandLyman-alphatransitspectraldatasetsreportedpreviously,wewilldescribeourobservationsusingthreenewmodes:i)STIS/NUVG230Lspectroscopy,off-limb,ii)STIS/CCDG750Mspectroscopyineclipse,andiii)WFC3/UVISimagingineclipse.TheseHSTGOprogram15419observationscomplementtwootherHubbleprogramsfocusedonFUVtransits(30orbits)andvisibleeclipses(10orbits),withatotalof95orbitsplannedfortheEuropacampaigns.ThefullprogramusesthreedifferentSTISspectralmodesandtwoWFC3narrowbandfilterstogloballyconstrainfar-UV,near-UVandvisibleauroralemissionsaswellasLyman-alphaabsorptionfromplumesinsunlight,eclipseandJupitertransit.EachvisitwillbecarriedoutduringoptimizedobservingconditionstomaximizethesensitivityofHSTtoplumesignals.We’lldiscussourearlyassessmentsofthesuccessfulnessofthevarioustechniques,includingcomparisonswithprevioustestsofotherlesssuitablemodes.Startingjustbeforethetimeofabstractsubmission,the~6monthprogramwillbe~2/3rdscompletedatthetimeoftheMOPmeeting.AdditionalconfirmationofandinformationregardingwatervaporplumesatEuropaisneeded.IoandEuropa:Influenceofvolcanicoutbursts,moon-footprintconnectionsandplumeactivity.Roth,L.,KTHRoyalInstituteofTechnology
WereviewselectedcharacteristicsofthemoonsIoandEuropaandtheirinteractionswiththeJovianmagnetosphereandshowsomerecentresultsfromongoingobservationstudiesonthereviewedtopics.ForIo,wediscussthelinesofevidencethatstochasticallychangingvolcanicactivitycausestransient,aperiodicchangesintheneutralenvironmentandmagnetosphere.In2017,wehaveobtainedsub-mmobservationswiththeIRAM/NOEMAinterferometerover5monthstomonitorsuddenchangesinIo'sbulkSO2atmosphereduetovolcanicoutbursts;preliminaryresultsarepresented.Inaddition,wediscusstherelationofIo'slocalUVaurorabrightnesstotheUVbrightnessofthemoon’sauroralfootprintonJupiter.ForEuropa,wereviewandcomparetheHSTandGalileoobservationsthatwererelatedtoplumeactivityandgiveanoverviewoverournew2018HSTplumeobservingcampaign.
88
![Page 89: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/89.jpg)
HSTLyman-αobservationsofUranusRoth,L.,KTHRoyalInstituteofTechnologyLamy,L.;Strobel,D.F.
SpectralandimagingultravioletobservationsofUranuswereobtainedbytheHubbleSpaceTelescope(HST)withinsixobservationcampaignsbetween1998and2017.WefocusonthespectralobservationsandanalyzethehydrogenLyman-α(HI1216Å)signalinthesedataaddressingafewunansweredquestionsregardingUranus'Lyman-αemission:WhatistheradialprofileofUranus'Hcorona?HowmuchoftheemissionsissolarfluorescenceandthusdirectlycorrelatedtothesolarLyman-αflux?WefurthermoresearchforlocalizedbrightnesssurplusesthatcanberelatedtoauroraandcomparepotentialauroralocationstoUranus'updatedrotationalmagneticfieldgeometry.Sources,sinksandtransportofenergeticelectronsnearSaturn'smainringsRoussos,E.,MaxPlanckInstituteforSolarSystemResearchKollmann,P.,Krupp,N.,Paranicas,C.,Dialynas,K.,Jones,G.H.,Mitchell,D.G.,Krimigis,S.M.,Cooper,J.F.
WepresentthefirststatisticalinvestigationthatfocusesonthetransitionregionbetweenSaturn'selectronradiationbeltsandtheplanet'smainringsusingMIMI/LEMMSmeasurementsfromCassini'sProximalorbits.Saturn'sdenseA-ringpresentsanimpermeableobstacleevenforthehighestenergyelectronsthatcanbemeasuredwithLEMMSsoitwasnaturallyexpectedtoobserveasharpdropoutofenergeticelectronfluxesatthatrings'outeredge(~2.27Rs).Despitethat,thisinnerboundaryoftheelectronbeltswasfoundconsistentlybetween1200and6000kmawayfromtheA-ringfor41outofthe45crossingsofthisregionbyCassini.Theboundary'saveragelocationmapswellwithinSaturn'sF-ring(~2.32Rs),anarrow,dynamicandlongitudinallyasymmetricringofSaturn,suggestingthattheF-ringmaycontributetothegloballossesofelectronsbeforethesegettransportedontotheA-ring.Morelikely,however,isthecasethattheinnerboundaryoftheelectronbeltswasdisplacedbyconvectiveflowstoitsobservedlocation.Thislocation'sdistancefromtheringswasfoundtooscillatewithacharacteristicsolarperiodicity,revealingtheinfluenceofsolarwindverydeepintoSaturn'smagnetosphere.Theeffectsoftheseconvectiveflowsbecomenoticeablealsothroughaseriesoflocaltimeasymmetriesobservedatthebelts-ringstransition.ThemoststrikingasymmetryidentifiedwasthatoflocalizedMeVelectronintensityenhancements("microbelts")centeredwithintheF-ringandonlyinthepost-noonsectoroftheelectronradiationbelts.WeproposethatthesemicrobeltscontainenergeticelectronsinneardriftresonancewithcorotationthatarelocallyproducedbyGalacticCosmicRaycollisionswiththeF-ringandgettrappedinlocal-timeconfinedtrajectoriesduetothepresenceoftheaforementionedconvectiveflows.
89
![Page 90: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/90.jpg)
CharacterizingLocalandInterplanetaryControlofJupiter'sAuroralDawnStormsusingHSTandJunoRutala,M.J.,BostonUniversityClarke,J.T.
ThedegreetowhichJupiter'sauroraarebrightenedbyvariousinterplanetaryprocessesandsolarconditionsisacomplexquestion,compoundedbythepresenceofthreedistinctauroralzones:thebrightauroraloval,footprintemissioncausedbytheGalileanmoons,anddiffusepolaremission.Recentresearchhasfocusedontheresponseofthebrighteningofthewell-definedauroralovaltointerplanetaryandlocalprocesses;thespecificresponseofthediffusepolaremissiontothesamestimuliremainsanopenquestion.Ourinterestliesinacomponentofthispolaremissionknownasdawnstorms:relativelybrightemissionwhichremainsfixedatmagneticlocaldawn.BycouplingobservationsofJupiter'sdawnstormsfromarecentHSTcampaignrunningfrom2015through2017within-situmeasurementstakenbyJuno,weintendtocharacterizehowthedawnstormsform.Specifically,wecomparethemorphologyandintensityoftheaurorainalargersetofHSTobservationsthanhavepreviouslybeenavailabletoconcurrentinterplanetarymeasurementsinordertoshowwhichconditionsarenecessaryfordawnstormstoformandbrighten.JunoobservationsofenergeticchargedparticlesassociatedwithJupiter’saurora.Rymer,A.M.,JHUAPLMauk,B.;Kollmann,P.;Haggerty,D.;Clarke,G.;Paranica,C.
JunohasbeeninhighinclinationorbitatJupitersinceAugust2016.OfthenumeroussurprisesaffordedbytheexcellentinstrumentsuitefromthisuniquevantagepointhavebeenconsistentobservationsofupwardelectronsapparentlyassociatedwithJuno’scrossingofJupiter’sauroraloval–thisinitselfisnotnecessarilyunexpectedbutoncomputingtheenergyfluxassociatedwiththeplanetwardversusanti-planetwardelectronbeamsweoftenfindthat–inregionsthataremostobviouslyassociatedwiththemainauroraloval-thefluxofanti-planetwardelectronsexceedsthatofthosegoingdownward[Mauketal.,2017].HereweextendtheworktoincludeallJunocrossingstodatetopresentthemostrecentcontextoftheseobservationsatJupiter.
90
![Page 91: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/91.jpg)
PlanetaryandexoplanetaryobservationswiththeHaleakalatelescopesandafuture1.8-moff-axistelescopeprojectPLANETSSakanoi,T.,TohokuUniversityKagitani,M.,Nakagawa,H.,Kuhn,J.R.,Berdyugina,S.V.,Emilio,M.,Obara,T.,Kasaba,Y.,Scholl,I.F.,Okano,S.,Kita,H.,Kimura,T.,Yoshikawa,I.,Berdyugin,A.,Piirolah,V.
WereportrecentscientificoutputsobtainedwiththeHaleakalaT40andT60telescopesincludingtheJuno-Hisakicampaignperioddata,andalsopresentafutureprojectPLANETS.Continuousmonitoringisessentialtounderstandtheplanetaryatmosphericphenomena,andtherefore,ourownfacilitieswithevensmall-andmediumsizedtelescopesandinstrumentsareimportant.ThelocationofourtelescopesatthesummitofMt.Haleakala,issufficientlyhigh(3050m),andoneoftheworldbestsiteswithclearskyconditions.
UsingT40andT60telescopes,wearecarryingoutcontinuousmonitoringoffaintatmosphericfeaturesofIoneutralgasandplasmatoruswhichareresponsibleforIo’svolcanicactivities.Forthelong-termtrendofIo’ssodiumemission,theintensitydecreasedduringtheperiodfrom1999to2005,andthenincreasedafter2005.FortemporaryenhancementsofIo’ssodiumemission,weshowedgoodrelationshipbetweensodiumemissionandoxygenemissionat130nmobtainedwithHisakiontheeventinJanuary2015.WealsoobtainedpositivecorrelationbetweensodiumemissionandIRaurorameasuredbyIRTFassociatedwithsolarwindshockfromJunodatainMay2016.Inaddition,weconcentrateondevelopinginstruments.Theseactivitiesareopentoanypossiblecollaborators.Ourandguestinvestigators’observationsarealsolinkedtospacecraftmissionsforMercury,Venus,MarsandJupiter.
Wearecarryingouta1.8-moff-axistelescopeprojectPLANETSatHaleakala,whichismanagedbythePLANETSFoundation(www.planets.life)underinternationalcollaborationofJapan,USA,Germany,Brazil,andFrance.Thisoff-axisopticalsystemwillenableustomeasureverylow-scattering-lightcontaminationandhigh-contrastdata.ThemainmirrorismadeofClearceramZ-HSblank,whichisnowonthefinalpolishingprocessinMaui.Inthispresentation,wegivethemostrecentprogressofthedevelopmentofprimarymirror,andstatusofthisproject.Resultsfrom2yearsofhightime-spacesamplingofJupiter’sradiationwithJUNO/MWRSantos-Costa,D.,SouthwestResearchInstituteBolton,S.J.,Levin,S.M.,Janssen,M.A.,Gulkis,S.,Oyafuso,F.,Brown,S.T.,Steffes,P.,Bellotti,A.,Adumitroaie,V.,Connerney,J.E.P.
Forthepasttwoyears(Perijove1thru13),theJunoMicroWaveRadiometer(MWR)hascontinuouslymeasuredathighresolutionstheradiationemittedbyJupiterandthesurroundingenvironment,overafrequencyrangefrom0.6to22GHz,fromJuno’shighlyelliptical53-daypolarorbitaboutJupiter.TheradiosourcesmeasuredbyJUNO/MWRareprimarilygeneratedbytheplanet,sky(i.e.cosmicmicrowavebackground),andultra-relativisticelectronsboundtotheJoviansystembythemagneticfield.Allthreeradiosourcesdemonstrateasignificantdependenceonthefrequencyofobservation.Inthispaper,wepresentanoverviewofourcurrentunderstandingofthedifferentsourcesofsynchrotronemissionthathavebeenidentifiedfromtheanalysisofJUNO/MWRandJUNO/MAGdatasets.Ourresultscurrentlypointtowardsthreedistinctivesourcesofsynchrotronradiationofdifferentsignalstrengths:theinnerelectronbelts(<4Rj),electronsseemlytrappedbetweenIoandEuropa(~6-9Rj),andnearfield-alignedelectronsfromthemiddlemagnetosphere.AfterabriefdescriptionoftheMWRinstrumentanditsscienceobjectives,wedescribehowweidentifythedifferentsourcesofsynchrotronemissionsandspeculateonthelarge-scaledynamicalbehavioroftheelectronpopulationsatJupiterthatmayexplaintheirrespectiveorigins.
91
![Page 92: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/92.jpg)
ResponseofJupiter'smagnetospheretovaryingsolarwindconditions:InsightsfromglobalMHDsimulationsSarkango,Y.,UniversityofMichigan-AnnArborJia,X.,Toth,G.,Hansen,K.C.
Jupiter'smagnetosphereisdrivenpredominantlybyinternalprocessesduetorapidrotationandpresenceofinternalsourcesofplasma.RemoteobservationsofJupiter'saurorahavehintedatacorrelationbetweenupstreamchangesandauroralbrightness,buthowtheexternalfactorslikethesolarwindandIMFinfluencethemagnetosphereremainsanopenquestion.WeusetheglobalMHDcode,BATSRUS,tosolvethesemi-relativisticsingle-fluididealMHDequationsinalarge3DdomaintomodeltheJovianmagnetosphere.MassloadingassociatedwiththeIoplasmatorusisincludedinourmodelthroughsourcetermsintheMHDequations.TounderstandhowJupiter'smagnetosphererespondstothesolarwindforcing,wedriveourglobalmodelwithdifferentidealizedupstreaminputscontainingdynamicpressureenhancementsanddifferentIMForientations.Wecomparethedistributionofplasmadensity,temperatureandplasmabetatoin-situobservationsforvalidation.Togaininsightintotheresponseofauroratosolarwindvariations,weanalyzethechangesinfieldalignedcurrentsinourmodeledionosphereinresponsetodifferentidealizedupstreamconditions.Wealsoexaminehowtheopen-closedfieldlineboundaryinoursimulationvarieswiththeupstreamconditions,andcomparethatwiththechangesinthefieldlinecurrents.Asaproxytocharacterizetheglobalcouplingefficiencybetweenthesolarwindandthemagnetosphere,wealsocalculatethereconnectionpotentialacrossthemagnetopausefordifferentsolarwindandIMFconditionsandcomparethatwithresultsfromempiricalmodeling.Wave-ParticleInteractioninJupiter'sMagnetosphere:AuroralandMagnetosphericParticleAccelerationSaur,J.,UniversityofCologneSchreinerA.,JanserS.,ClarkG.B.,MaukB.H.,KollmannP.,EbertR.W.,Allegrini,F.,SzalayJ.
Weinvestigatespatialandtemporalscalesatwhichwave-particleinteractionoccursinJupiter'smagnetosphere.Weconsiderelectrons,protonsandheavyionsandstudytheregionsalongamagneticfluxtubewheretheplasmaisthedensest,i.e.,theequatorialplasmasheet,andwheretheplasmaisthemostdilute,i.e.,atthehighlatitudes,nearwhichauroralparticleaccelerationisexpectedtooccur.Wecross-comparethekineticplasmalengthandtemporalscalesintheseregionsassumingbothregionsareconnectedthroughAlfvenwaves.Guidedbythiscomparison,weinvestigatetheroleofelectronLandaudampingofkineticAlfvenwavesinstochasticallyconvertingelectromagneticfieldenergyintoauroralparticleacceleration.WealsopresentpropertiesofthedispersionandpolarizationrelationshipsofkineticAlfvenwavesintheaccelerationregion,wheretherelativisticcorrectionstemmingfromthedisplacementcurrentinAmpere'slawisessentialtobeincluded.Finally,wediscusstheimportanceofioncyclotrondampingoftheheavyionsinheatingthemagnetosphericplasma.
92
![Page 93: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/93.jpg)
AnInvestigationofSuppressionofMagneticReconnectionatSaturn’sMagnetopauseSawyer,R.P.,UniversityofTexasatSanAntonioFuselier,S.A.;Mukherjee,J.;Petrinec,S.M.;Masters,A.
Magneticreconnectionisthefundamentalprocessthatmediatestheinteractionbetweenthesolarwindandaplanetarymagnetosphere.However,Saturnisafastrotatingplanetwhichleadstoastronginternallydrivenmagnetosphere.Thisinternaldominancemayproduceco-rotationalflowsasfaroutasthemagnetopause.Theresultingshearflowacrossthemagnetopausemaythenacttosuppressreconnection.PredictionshavebeenmadeastowherethissuppressionoccursatthemagnetopauseofSaturn.Inthisstudy,weexaminedmagnetopausecrossingeventsfromCassiniundernorthwardIMF,whereheatedelectronswereobservedinthemagnetosheath.Theseheatedelectronsprovideevidenceofreconnectionatthemagnetopause.Theelectronspectrometer(ELS)portionoftheCassiniplasmaspectrometer(CAPS)suiteprovidedobservationsoftheelectrondensityandtemperaturesaswellaselectronpitchangledistributionsandtheirassociatedenergies.Furthermore,weusedamodifiedmaximummagneticshearmodeltodeterminethelocationofthereconnectionlineonSaturn’smagnetopause.Wethencomparedourpredictedlocationofthereconnectionlinetopredictedregionswherereconnectionmightbesuppressed.Fromthiscomparison,severalinstanceswerefoundwithinthepredictedsuppressionregionswheresignaturesofreconnectionwereobserved.VisibleWavelengthSpectroscopyoftheIoTorusDuringtheHisakiMissionSchmidt,C.A.,BostonUniversitySchneider,N.,Leblanc,F.,Gray,C.,Morgenthaler,J.,Turner,J.,Grava,C.
EmissionsinIo'storusofferauniqueopportunitytosnapapictureofamagnetospherethroughthelensofatelescope.WereportonspectroscopicobservationswiththeARC3.5matApachePointObservatory,measuringradialdistributionsofeightemissionlinesofS+,O+,andS++atvisiblewavelengths.TheresultscomplementandindependentlyconfirmkeyHisakifindings.Thetorus'dawn-duskdisplacementisconsistentwiththeelectricfieldstrength(3.8mV/m)andvariability(1-8mV/m)inferredfromtheEUVbrightnessasymmetry.AsintheEUV,thevisibletorusalsoshowsbrightnessenhancementsatlongitudesneartheintersectionoftheorbitalandcentrifugalplanes.Previouslyunseencharacteristicsyieldadditionalinsights.EmissionenhancementsdownstreamofIoareobservedforthefirsttimeinthevisible.ThisIophaseeffectdiffersfromthatintheEUVandlagsfurtherbehindtheimmediatewake.SuchmayreflectdensityandtemperatureperturbationsastheplasmasweepspastIo,offeringimportantcluesabouthowthemoon'satmosphericlosssuppliesthetorus.InnercoldtorusemissionsareonlyobservedfromS+transitions<2eV.RadialdistancestothecoldtorusandribbonfeaturesdependonJovianlongitudeindistinctlydifferentways,posingnewinformationabouthowJupiter'sfieldregulatestheplasmatransportinthesepopulations.
93
![Page 94: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/94.jpg)
ASearchforIonScaleHeightVariabilityinHisakiIoTorusObservationsSchneider,N.M,LASP,U.ColoradoC.A.Schmidt,M.Kagitani,Y.Kasaba,T.Kimura,G.Murakami,F.Tsuchiya,A.Yamakazi,I.Yoshikawa,K.Yoshioka
IontemperatureisacriticalvariableinIoplasmatorusenergetics,butisdifficulttoderivefromremotesensingmeasurements.Therelativeimportanceofhotionsvs.hotelectronsinpoweringthetorusemissionsremainsanopenquestion.Torusbrightenings,whethercausedbyepisodicchangesinthevolcanicsupplytothetorusorperiodicSystemIII/IVenhancements,offerthebestchancetosearchfordrivingvariationsinhotelectronsorions.Muchattentionhasbeenpaidtohotelectronpopulations,derivablefromdetailedspectralmodeling,butlessworkhasbeendoneoniontemperature.Ground-basedstudieshavesuccessfullyderivedT⊥fromveryhighresolutionspectra,andTllfromscaleheightmeasurementsinimages,bothoverlimiteddatasets.Schneideretal.1997foundstronglongitudinalvariationsinTllduringaweek-longdataset,andanti-correlatedSystemIIIbrightness,butmoreextendedfollowupdatasetshavenotpreviouslybeenavailable.
TheHisakidatasetpresentsthepossibilityofanunparalleledopportunitytostudylong-termandshort-termvariationsiniontemperatures.Theinstrumentisnotdesignedtotakeimagesofspecificemissions,butitslargeentranceslitacceptsthefullheightandwidthofthetorus.Intheidealcase,eachspectralemissionfeaturewouldappearasanimageofthetorusatitsappropriatepositioninthespectrum,creatingan“overlapogram”(asdidtheCassiniUVISinstrument).Inreality,theemissionsareblurredduetoinstrumentalresolutionandaberrations,andmultiplespectralfeatureoverlap.Furthermore,thechangingopeningangleoftherotatingtorusaddsaspuriousapparentscaleheightvariationwhichmustberemoved.Withallowancesforalltheseeffects,wewillreportonoursearchforiontemperaturevariationsduringthefirsttwoyearsofHisakiobservations,andcompareourresultstoapreviousindependentstudybyM.Shishido(M.S.thesis,U.Tohoku).
DistributionofhotionplasmainSaturn’smiddlemagnetosphere,from>13yearsofCassiniorbitsSergis,N.,AcademyofAthensAchilleos,N.A.,Guio,P.,Arridge,C.S.,Sorba,A.M.,Roussos,E.,Paranicas,C.,Krimigis,S.M.,Dougherty,M.K.,Hamilton,D.C.,N.Krupp,N.,Mitchell,D.G.
InthisstudyweexpandpreviousworkdonebySergisetal.(2018)forCassini’sProximalOrbits,usingCassiniparticleandmagneticfielddatatoquantifyboththesteadystateandthedynamicsoftheSaturnianmagnetosphere-asrevealedthroughthevariabilityoffundamentalplasmaparameterssuchashotionpressureandrelatedplasmabeta.ByemployingtheUCL/Achilleos-Guio-Arridge(UCL/AGA)magnetodiskmodel,wemapthesequantitiestothemagneticallyconjugatepositiononSaturn’srotationalequator,producingequivalentequatorialradialprofilesfortheseparameters.Asourrecentresultshaveindicated,theUCL/AGAmagnetodiskmodelprovidesagoodapproximation,forthesepurposes,oftheadditionalmagneticfieldgeneratedbythedistributedcurrentflowingintheSaturnianmagnetodisk.Themodelcanthusbeusedtoprojectdatawithreasonablygoodaccuracyfromhighlatitudestothemagneticallyconjugateregionsattheequator.Inthiswork,weexpandonourinitialProximal-Orbitstudybyincludingdatafromothernon-equatorialCassiniorbits,thusexploitingallavailablehotplasmameasurementsfromthemissiontoproducethemostcompletepicturetodateofSaturn’sringcurrentandglobalplasmaenvironment.
94
![Page 95: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/95.jpg)
Gemini-TEXESmid-infraredspectralobservationsofJupiter’sauroralregions:comparisonwithultravioletandnear-infraredobservationsSinclair,J.A.,JetPropulsionLaboratory/CaltechOrton,G.S.,Greathouse,T.K.,Lacy,J.,Giles,R.S.,Momary,T.,Grodent,D.,Bonfond,B.,Fletcher,L.N.,Irwin,P.G.J.
Jupiterexhibitsauroralemissionoveralargerangeofwavelengths.AuroralemissionatX-ray,ultravioletandnear-infraredwavelengthsdemonstratetheprecipitationofionandelectronsinJupiter’supperatmosphere,ataltitudesexceeding350kmabovethe1-barlevel.Enhancedmid-infraredemissionofstratosphericCH4,C2H2,C2H4andfurtherhydrocarbonsisalsoobservedcoincidentwithJupiter’sauroralregions.OnMarch17-19th2017,weobtainedspectralmeasurementsofH2S(1),CH4,C2H2,C2H4andC2H6emissionofJupiter’shighlatitudesusingTEXESonGemini-North.ThisrareopportunitycombinesboththesuperiorspectralresolvingpowerofTEXES(R≤85000)andthehigh-spatialdiffraction-limitedresolution(~2°latitude-longitudefootprintat70°N)providedbyGemini-North’s8-metreprimaryaperture.ThehighspatialresolutionhasforthefirsttimerevealedtransientspatialstructureintheemissionofCH4,C2H2andC2H4inJupiter’snorthernauroralregion.FromMarch17thto19th2017,duringasolarwindcompression,adusksidebrighteningofthesespecieswasobservedinthenorthernauroralregion.Wewillpresentaretrievalanalysisoftheseobservationstodemonstratethealtitudesintheatmosphereandthemagnitudeoverwhichtemperaturesandhydrocarbonabundancesweremodifiedduringthisevent.Wewillalsocomparethemorphologyofthemid-infraredemissionwithnear-simultaneous(i)HST-STISimagesoftheultravioletauroralemissionand(ii)IRTF-SpeXobservationsofthe3.42-μmH3
+emission.ConfirmingandconstrainingthepresenceofaEuropa-generatedneutral(asymmetric)torusSmith,H.T.,JohnsHopkinsUniversityAppliedPhysicsLabMauk,B.H.,Johnson,R.E.,Mitchell,D.G.
Neutraltoricanprovidekeyinsightinlargeplanetmagnetospheres.Thesefeaturesformwhenparticlesescapeandformapopulationthatco-orbitswiththemoon.Toridistributionsandcompositionsareadirectresultofthesatellitecompositionandsourcemechanisms.Thus,understandingthefeaturescanoftenprovidecriticalinsightintothesourcemoonsthatmightbedifficulttodirectlyobservable.
ThepotentialhabitabilityofJupiter’smoon,Europa,isofparticularinterest.DetectionofaEuropa-generatedneutraltoruscouldprovideimportantinsightintothismoontoincludecriticalevidenceofpossibleactivity.ThefirstindicationsofsuchafeaturewerereportedbyLaggetal.(2003)whoproposedthepossiblepresenceofaneutraltorusinthevicinityofEuropa'sorbitbasedontheobservedenergeticelectronpopulation.Mauketal.(2003)thenreportedthedetectionofaEuropaneutraltorusbyimagingenergeticneutralhydrogenatomsproducedfromchargeexchangeinteractionswithaneutraltorus.However,unlikeatSaturn'smagnetosphere,whereneutralparticlesdominateoverchargedparticles,Jupiter'smagnetosphereisdominatedbychargedparticles.Insuchahighradiationenvironment,ENAscouldalsobeproducedasaresultofchargeexchangeinteractionsbetweentwoionizedparticles.Inthatcase,theENA’scannotbeusedtoinferthepresenceofneutralparticlesbecausetheycouldbeproducedbyinteractionswiththemoreextended(anddominant)Ioplasmatorus.
Forthispresentation,weexaminetheviabilitythattheMauketal.(2003)observationswereactuallygeneratedfromaneutraltorusemanatingfromEuropa.TheseresultsarethencombinedtoreconstructandplaceconstraintsontheEuropaneutraltorus.
95
![Page 96: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/96.jpg)
TowardsaUnifiedTheoryofAuroralParticleAccelerationatEarthandJupiterSong,Yan,UniversityofMinnesotaRobertL.Lysak
EarlyobservationsfromNASA'sJunomissionhaveshownmanysurpriseresults.Amongthefindings,theobservationsofthepowerfulJupiter’saurorasaresurprisinglydifferentfromaurorasatEarth.Inthispresentation,wewilldescribedynamicaltheoriesrelatedtothemechanismsoftheauroralparticleaccelerationandthegenerationofhighenergyparticleaccelerators,whichincludemainly(i)thedynamicaltheoryofthegenerationofelectrostaticfieldsandfieldalignedcurrents,(ii)bothquasi-staticandAlfvenicarcformationhaveAlfvenicnature,andcanbedescribedbyaunifiedtheory;(iii)thegenerationofhighenergyparticlegenerators,suchasAlfvenicdoublelayersandchargeholesinauroralacceleration,whichcanaccelerateparticlestohighenergy.
WewillexaminetheapplicationofthesetheoriestotheinterpretationoftheobservedJovianaurorae.Investigatinghowthelarge-scalestructureofSaturn’smagnetospherevarieswithlocaltimeusingacombineddataandmodelingapproachSorba,A.M.,UniversityCollegeLondonAchilleos,N.,Sergis,N.,Guio,P.,Arridge,C.andDougherty,M
Saturn’smagnetospherehassignificantinternalplasmasources.Cold,denseplasmaintheequatorialregionoriginatingfromtheicymoonEnceladus,coexistswithahotter(>3keV)plasmapopulationoriginatinginSaturn’soutermagnetosphere,whichisobservedtobemuchmorevariablewithradialdistanceandlocaltime.Thishotplasmacontributestotheformationofadisc-likemagneticfieldstructureviaanenhancementofthemagnetosphericringcurrent,andalsoinfluencespressurebalanceatthemagnetopauseboundary,causingthemagnetospheretoinflate.However,theoriginofthispopulation,andtheextenttowhichitcontrolsmagnetosphericstructureandsize,arestillareasofactiveresearch.
Inthisstudy,weusehotplasmamomentscalculatedfromCassiniMagnetosphericImager(MIMI)data,incombinationwithanaxisymmetricforce-balancemodelofSaturn’smagnetodisk,toinvestigatehowthevariablehotplasmapopulationinfluencesthelarge-scalemagnetosphericstructure.Inparticular,weuseequatorialprofilesofaveragehotplasmapressurecalculatedfordifferentlocaltimesectorsasinputstothemagnetodiskmodel,tocreateafamilyofmodelsthatdescribeSaturn’smagnetosphereacrossalllocaltimes.Inthisway,weinvestigatehowtheglobalmagneticfieldstructureandpressurebalancevaryacrosslocaltime,tobuildaglobalpictureofSaturn’smagnetosphere.WethencomparethesemodelresultstoobservationsmadebytheCassiniMagnetometer(MAG)instrument.ThisstudyaimstoadvanceourunderstandingofglobalpressurebalanceinSaturn’smagnetosphere.
96
![Page 97: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/97.jpg)
GenerationofULFwavesbytheDrift-MirrorPlasmaInstabilitySoto-Chavez,A.Rualdo,NewJerseyInstituteofTechnologyLanzerotti,Louis,Gerrard,A.,Cohen,R.,Cooper,M.,andManweiler,J.W.
Thehotplasmaconditionsofthemagnetospheresofthegiantplanetspresentenvironmentsthatcanbesourcesofinternally-generatedwaves.Amongtheseareultra-lowfrequency(ULF)wavesgeneratedbytheDrift-Mirror(DM)plasmainstability.TheDMinstabilityusuallyrequirestheplasmabeta(β)parametertobeβ>1.Becauseofthis,itisdifficulttostudytheDMinstabilityinconfinedlaboratoryplasmaexperimentswhereusuallyβ<1.Therefore,astrophysicalmagnetizedobjectsaretheonlyenvironmentsthatonecanusetotesttheories/models,predictions,andconsequencesoftheDMplasmainstability.WehaveconclusiveevidenceofaULF(Pc4-5range)wavegeneratedbyDMplasmainstabilityinEarth’sinnerMagnetosphere.Dataanalysis,fromtheRadiationBeltStormProbesIonCompositionExperiment(RBSPICE)onboardNASA’sVanAllenProbesSatellites,demonstratesthattheDMplasmainstabilityconditionforsingleandmultiplespeciesiswellsatisfied.Weareabletomeasurethewavegrowthrate,forthefirsttime,anddemonstratethatitagreeswellwiththepredictedlineartheorygrowthrate.Wealsopresentovertwo-yearmeasurementsofhigh-betaeventstakenbytheRBSPICEinstrument.TheimplicationsofthesenewmeasurementsandtheirroleinEarth’sinnermagnetospherearediscussedforunderstandingwave-particleinteractions,suchasparticleaccelerationanddiffusion,inthemagnetospheresoftheouterplanets.Saturnianplanetaryperiodoscillations,angularmomentumtransferandplasmasub-corotationSouthwood,D.J.,ImperialCollegeLondonUKHunt,G.J.,Dougherty,M.K.
ThehighinclinationorbitsofCassiniin2008revealedthelatitudinalstructureofboththequasi-steadyfieldalignedcurrents(FACs)andthenorthernandsouthernFACsystemswith~10.7hrperiodicity.TheF-ringandproximalorbitshaveconfirmedthegeneralstructurebutwithamplitudesweaker,probablyduetoseason.Thepeakamplitudeoftheperiodiccurrentisverysimilartothesteadycurrentandbothpeaksoccuratasimilarlatitudeintheauroralzone.Theperiodicsystemsarethesourceofthefamiliarglobalmagneticplanetaryperiodicoscillations(PPO)detectedbytheCassinispacecraftmagnetometerthroughoutthemagnetosphere.Thequasi-steadycurrenthasbeenbelievedtobetheprimarymechanismforcouplingangularmomentumfromtheionospheretothemagnetospheretoheavyionisedmaterialoriginatingfromtheinnermagnetosphereandbeingtransportedoutwardsonclosedfieldlines.Wequestionthatassumptionhereasthesteadycurrentsystemseemstobeprimarilylocatedatinvariantlatitudesabove70deg.Indeed,weproposethatthemajorangularmomentumtransferfromionospheretomagnetosphereonclosedfieldlinesisaccomplishedbythePPOsignals.AsimpleMHDargumentshowsthatthemotionofplasmainducedbythePPOisarotationinthesamesenseastheplanetintheclosedfieldregion.TheangularmomentumdensityinthePPOsignalcanbecalculated.Itisinthesamedirectionastheplanetaryrotation.Moreover,in2013wherenorthernandsouthernsignalshadthesamefrequencyandwerelockedinphase,thephaseoftheoverallsignalswasconsistentwithangularmomentumbeingdepositedbytheoscillationsneartheequator.Thesameeffecthasbeenseenincomputations.Theradicalconclusionisthatthesub-corotationofplasmaintheclosedfieldregionoftheSaturnmagnetosphereiscontrolledbythePPOamplitude.
97
![Page 98: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/98.jpg)
SpatialDistributionofCondensedOxygenonEuropaSpencer,J.R.,SouthwestResearchInstitute
Condensedoxygen,probablygeneratedaspartofaradiolyticcyclethatincludesO3andH2O2,islikelytoplayanimportantroleinthecomplexchemicalenvironmentofthesurfacesoftheicyGalileansatellites.IthasbeenidentifiedonGanymede(Spenceretal.1995),andsubsequentlyonEuropaandCallisto(SpencerandCalvin2002)bymeansofitsshallowbutdistinctive5773and6250Angstromabsorptionbands.5773Angstrombandstrengthisupto2%onGanymede,butonly~0.3%onEuropa.O2onGanymedeexhibitsastrongconcentrationonthetrailinghemisphere,suggestingamagnetosphericorigin,butthedistributiononEuropahasbeenpoorlyknownduetotheextremeweaknessoftheabsorptionband.WereportonthehighestSNRspectroscopyoftheO2bandsonEuropayetobtained,usingtheDeVenySpectrographonthe4.3-mLowellDiscoveryChannelTelescopeinJune2017.TheimprovedSNRofthenewdataprovidesthebestconstraintsyetonthelongitudinaldistributionofO2onEuropa,whichmayprovidecluestotheoriginandevolutionofthisspecies.
QuantifyingthestressofSaturn'smagnetosphereduringtheentireCassinimissionStaniland,N.R.,ImperialCollegeLondonDougherty,M.K.,Masters,A.
IntheinnerregionofSaturn’srotation-dominatedmagnetosphere,thegoverningmagneticfieldcontributorsaretheinternalfieldandthecurrentsheet.AzimuthalcurrentsflowingintheequatorialplasmadiskradiallystretchSaturn’smagneticfieldlinesintoa‘magnetodisc’geometry.Theextentofthiseffectvariesduetobothexternalandinternaldynamicalprocessesthatcanstretchandcompressthesystem.
Inthisstudy,weusethecompletedatasetcollectedbytheCassinispacecrafttocharacterisethestressofSaturn'smagnetosphere.Wefitamodelofthenear-equatorialregionoftheinnermagnetospheretodeterminewhetherthesystemiscompressed,stretchedornearsomeprescribedgroundstate.ResultsshowthattrackingvariationsinthecurrentintensityofSaturn’smagnetodiscaccountsforchangesinthestressofthesystem.Approximatelytwothirdsofourdatasetiswelldescribedbythemodel,signifyingasteady-statecurrentsheetduringthesepasses.Thisworkfurtherindicatesthatthereisageneraltrendintheaveragecurrentparameterperlocaltimesector,whichagreeswithourpreviousassumptionsthatSaturn’smagneticfieldisasymmetricabouttheaxisofrotation.Additionally,wenotevariationsduetoseasonalchangeandthesolarcycle,andalsodiscussthestressduringnon-steady-statepasses.WeconcludethatSaturn'smagnetosphereremainednearitsgroundstateforasignificantperiodoftheCassinimission.
98
![Page 99: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/99.jpg)
AnewempiricalmagneticfieldmodelforSaturn'smagnetosphereStephens,G.K.,TheJohnsHopkinsUniversityAppliedPhysicsLaboratoryMitchell,D.G.;Paranicas,C.;Sitnov,M.I.;Vandegriff,J.D.
WepresenttheinitialfindingsonanempiricalmodelofSaturn’smagneticfield,usingCassinimagnetometerdata,whichgoesbeyondtheinternalfieldanddescribesthefieldduetoexternalcurrentsystems,suchastheringcurrentandmagnetopausecurrent.ItfollowstheapproachesusedinTsyganenkoTerrestrialmagneticfieldmodelsandinparticulartheTS07Dmodel,whichfundamentallychangedhowtheEarth’smagnetosphericmagneticfieldwasmodeled.First,theclassicalapproachofhand-tailoringthecurrentdescriptionswasreplacedwitharegularexpansionoforthogonalbasisfunctions.Secondly,dataminingisusedtocapturethemodel’stimeevolutionandreplacesthefunctionaldependenceonsolarwindparametersandgeomagneticindicesusedinearliermodels.Together,thesechangessoughttomoreeffectivelyutilizeinformationcontainedinthedatabyincreasingthemodel’sflexibilityfromtheeliminationofrigiddescriptionsofthecurrentsystemsandtheirdynamics.CoupledinteriorstructureandexteriorplasmamodelsofEuropaStyczinski,M.J.,UniversityofWashington
Inthesearchforlifeelsewhere,Europamaybethetopcandidate.Remotesensingdatasuggestthatbeneathitsicyshellliesaliquidwaterocean,incontactwitharockysilicatemantle.MagneticfieldmeasurementsfromtheGalileomissionprovideastrongconfirmationthatEuropahasasubsurfaceocean;aninducedmagneticfieldisobservedthatimpliesaconductinglayerconsistentwithsaltywater.However,Europaisimmersedinacomplexplasmaenvironmentthatreactsto—andgenerates—itsownmagneticfields,complicatinganyandallattemptstomodelEuropa’smagneticinduction.PaststudiesofEuropa’soceanstructurehaveappliedsimplifiedmodelsforEuropa’sinterior,orincompletemodelsofthesurroundingplasmaenvironment.
Inthiswork,wesimulateEuropa’smagneticinteractionswithcoupledmodelsforboththeinteriorandexterior,tobetterunderstandhowoceanstructureaffectsEuropa’smagneticinductionsignature.Weapplya1DthermodynamicmodelfortheinteriorofEuropa,generatedbyPlanetProfile,toobtainrealisticgeophysicalparameterssuchaselectricalconductivity.
Theseparametersforminputsto3DglobalmultifluidsimulationsofEuropa’sinductionandplasmaenvironment.Theresultingcoupledmodelhasstrongexplanatorypower,throughself-consistentmodelingofplasmabehaviorovermanyscaleranges,flexiblerepresentationofinteriorconductinglayers,andmoreaccurateaccountingofplanetaryandupstreamplasmaconditions.
Adetaileddescriptionofourcoupledmodel,initialresults,andplansforitsusewillbepresented.
99
![Page 100: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/100.jpg)
AuroralhissemissionsduringCassini’sGrandFinale:DiverseelectrodynamiccouplingbetweenSaturn,itsrings,andEnceladusSulaiman,A.H.,UniversityofIowaKurth,W.S.,Hospodarsky,G.B.,Averkamp,T.F.,Persoon,A.M.,Ye,S.-Y.,Menietti,J.D.,Pisa,D.,Farrell,W.M.,Gurnett,D.A.
TheCassiniGrandFinaleorbitsofferedanewviewofSaturnanditsenvironmentowingtomultipleorbitsofhighinclinationandunprecedentedproximitytotheplanet.TheRadioandPlasmaWaveScience(RPWS)instrumentdetectedstrikingsignaturesofintenseauroralhissemissionsduringthisphase.Ourresultsshow:1)Anemissiondetectedneartheionosphereandlikelyoriginatingfromanextendedsourceregionintherings.2)FirstobservationsofVLFsaucersdirectlylinkedtoSaturn’sionosphere.Botharebelievedtobeassociatedwithprevailingionosphere-ringcurrents.Andfinally,3)AnemissiondetectedneartheionosphereanddirectlylinkedtoEnceladus.ThesedetectionshavebeenaffordedexclusivelybytheGrandFinaleorbitsbyvirtueofhigh-latitudeandlow-altitudepasses.Altogether,theyrevealboththegreaterimportanceandspatialextentofwave-particleprocessesoperatingbetweenSaturn,itsrings,andEnceladus.ThefinalphaseofthemissionhasunderlinedSaturnasoneofthemostdynamicanddiverseenvironmentsinthesolarsystem.JunoObservationsConnectedtotheIoFootprintTailAuroraSzalay,J.R.,PrincetonUniversityB.Bonfond,F.Allegrini,F.Bagenal,S.Bolton,G.Clark,J.E.P.Connerney,R.W.Ebert,R.E.Ergun,G.R.Gladstone,D.Grodent,G.B.Hospodarsky,V.Hue,W.S.Kurth,S.Kotsiaros,S.M.Levin,P.Louarn,B.Mauk,D.J.McComas,J.Saur,P.W.Valek,R.J.Wilson
TheJunospacecraftcrossedfluxtubesconnectedtotheIofootprinttailatlowJovianaltitudesonmultipleoccasions.Thetransitscoveredlongitudinalseparationsofapproximately10˚to120˚alongthefootprinttail.Juno’ssuiteofmagnetosphericinstrumentsallowfordetailedmeasurementsofavarietyofphysicalparametersfortheIofootprinttail.Junoobservedplanetwardelectronenergyfluxesof~70mW/m2neartheIofootprint,and~10mW/m2fartherdownthetail,alongwithcorrelated,intenseelectricandmagneticwavesignatureswhichalsodecreaseddownthetail.Allobservedelectrondistributionswerebroadinenergy,possiblysuggestinganAlfvénicaccelerationprocess,anddidnotshowanyinverted-Vstructurethatwouldbeindicativeofaccelerationbyaquasi-static,discrete,parallelpotential.Here,wediscusstheJADE,UVS,Waves,andMagneticfieldmeasurementstakenduringJuno’stransitsthroughtheIofootprinttailfluxtubesduringperijoves5-7andcomparethesemeasurementswithexistingtheoreticalmodelsdescribingthetailformation.
100
![Page 101: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/101.jpg)
VolcanicControlofJupiter'sAuroraandMiddleMagnetosphereDynamicsObservedbyHisaki/EXCEEDandAnalysisImprovementsbyJunoTao,C.,NationalInstituteofInformationandCommunicationsTechnology(NICT)Kimura,T.,Tsuchiya,F.,Murakami,G.,Clarke,G.,Ebert,R.W.,Yamazaki,A.,Yoshioka,K.,Kita,H.,Misawa,H.,Badman,S.V.,Kasaba,Y.,Yoshikawa,I.,andFujimoto,M.
Jupiter'saurorareflectstheplanetarymagnetosphericandatmosphericenvironments.Sinceitslaunchin2013,theHisaki,Earth-orbitingplanetaryspacetelescope,hascollectedauniquelong-termdatasetofultravioletemissionsfromJupiter'sIoplasmatorusandaurora,undervarioussolarwindconditionsandIovolcanicactivity.WeanalyzedJupiterauroraspectratakenbytheEXCEED(ExtremeUltravioletSpectroscopeforExosphericDynamics)spectrometeronboardHisaki.TemporalvariationofJupiter'snorthernauroraduringenhancedIovolcanicactivitywasdetected.ItwasfoundthatinassociationwithreportedIovolcaniceventsinearly2015,auroralpowerandestimatedfield-alignedcurrentswereenhancedduringdaysofyear40–120.Furthermore,thefarultravioletcolorratiodecreasedduringtheevent,indicatingadecreaseofauroralelectronmeanenergyandtotalaccelerationby<30%.DuringtheepisodeofenhancedIovolcanicactivity,Jupiter'smagnetospherecontainsmoresourcecurrentviaincreasedsuprathermalplasmadensitybyupto42%;therefore,itwouldhaverequiredcorrespondinglylesselectronaccelerationtomaintaintheenhancedfield-alignedcurrentandcorotationenforcementcurrent.Sporadiclargeenhancementsinauroralemissiondetectedmorefrequentlyduringtheactiveperiodcouldhavebeencontributedbynon-adiabaticmagnetosphericenergization.
Inthispresentation,wealsodiscusstheimprovementsoftheremoteauroralanalysisreferringtodirectin-situobservationsachievedbyJuno.MagnetosphericStructureandDynamicsatSaturn(andmaybeJupiter)Thomsen,M.F.,PlanetaryScienceInstitute
SaturnandJupiterare,liketheEarth,stronglymagnetizedplanetspossessingpersistentmagnetospheres.UnliketheEarth,theprincipalsourcesofmagnetosphericplasmaforSaturnandJupiterareinternaltothemagnetospheres,namelygasesemanatingfromthemoonsEnceladusatSaturnandIoatJupiter.AlsounliketheEarth,thelargesizeandrapidrotationofSaturnandJupiterallowcentrifugalstressestodominatethemagnetosphericdynamics.Thecombinationofinternalplasmasourcesandstrongcentrifugaleffectsproducethetwoprincipaldynamictransportmechanismsattheseplanets:Thecentrifugally-driveninterchangeinstabilityandlossofplasmadowntailthroughmagneticreconnection.Wewillreviewthegeneraldynamiccycleinvolvingthesetwoprocessesandthenwilllookingreaterdetailattheirrelationshipandphysicalimplications.
101
![Page 102: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/102.jpg)
AuroralExcitationAlongOpenJovianMagnetosphericFieldLinesTrafton,L.M.,UniversityofTexasatAustin
ThemagneticfieldlinesatJupiter’shigherlatitudesareopentothespaceenvironment.HubbleUVandnear-IRimagesshowalooselystructured,mildlyvariableglowoveritspolarcapsinadditiontothebrightauroralovalscausedbytheprecipitationofelectronstrappedintheJovianmagnetosphere.TheglowattheselatitudesislikelytobeexcitedbychargedparticlesinthelocalspaceenvironmentthatarefocusedbytheJovianfieldlines.ThesolarEUVexcitationnearthepolescannotbeanygreaterthanitisatlowlatitudes,wheretheUVglowandemissionspectraareobservedtobemuchweaker.Potentialsourcesofpolarexcitationarethesolarwind,solarenergeticparticleevents,andfield-linereconnectioneventsintheJovianmagnetotail.
Wepresentpreliminarynear-IRspectrasamplingJupiter’spolarcapregionsintheL-band(~3.2microns)thatshowcomplexspatialvariability.BesidesH3
+andmethaneemission,thereappearstobeemissionfromotherhydrocarbons,oranunidentifiedspecies.Differentexcitationprocessesappeartobeatplay.
Multi-specieshybridmodelingofplasmainteractionsatGalileanmoonsTravnicek,P.,UCBerkeley,SSLSebek,O.,StverakS.,Walker,R.J.,Hellinger,P.
WestudyplasmainteractionsofGalileansatellitesbymeansofmulti-speciesglobalhybridsimulations.Weconsidermulti-speciesbackgroundplasmacomposedofoxygenandsulfurionsandmulti-componentneutralatmospheres.Furtherweconsiderionizationprocessesoftheneutralatmospherewhichisthenasourceofdensepopulationofpick-upions.Weapplyvariablebackgroundplasmaconditions(density,temperature,magneticfieldmagnitudeandorientation)inordertocoverthevariabilityinconditionsexperiencedbythesatelliteswhenlocatedindifferentregionsoftheJovianplasmatorus.Weexamineglobal3-dimensionalstructureoftheinteractions,formationofAlfvénwings,developmentoftemperatureanisotropiesandcorrespondinginstabilities,andthefinephenomenacausedbythemulti-specienatureoftheplasmacausedbytheenergyexchangebetweenparticlesandE/Mwaves).TheresultsareingoodagreementwithinsitumeasurementsofmagneticfieldandplasmadensitymadebytheGalileospacecraftwhichwealsodemonstrate.Theglobal3-Dnatureofournumericalexperimentsallowsusprovidedetailedanaylysisofinsituobservations.
102
![Page 103: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/103.jpg)
TheJovianIonosphericionpopulationobservedbyJuno'sJADEinstrumentValek,P.W.,SwRIAllegini,F.andBagenal,F.andBolton,S.andConnerney,J.andEbert,R.W.andGladstone,R.andKim,T.K.andKurth,W.andLevin,S.andLouarn,P.andMauk,B.andMcComas,D.andWaite,J.H.andWilson,R.J.
Juno’sJovianAuroralDistributionsExperiment(JADE)measuresplasmadistributionsusingtwonearlyidenticalelectronsensorsandoneionsensor.Theelectronsensors(JADE-E)measuretheelectrondistributionintherangeof100eVto100keVandtheionsensor(JADE-I)measuresthecompositionseparatediondistributionsintherangeof10eV/qto50keV/qforionswithmasses<64amu/q.TheJunospacecraft’shighvelocity(~50km/s)nearperijoveat~1.05RJ(1RJ~71,400km)facilitatesobservationsofverylowenergyions,tobelow1eV/qforprotons,inJupiter’sreferenceframe(whenviewinginthespacecraftramdirection).Duringperijovepasses,whenthespacecraftisatsub-aurorallatitudes,observationsrevealtwopopulationsofions:thoseofIogenicoriginandthosedirectlysampledfromtheionosphere.Theionosphericpopulationconsistsoflowenergy,lightions,mostlyprotons.Theyhaveenergiesbelow100eVinthespacecraftframe,andextenddowntothebottomoftheJADEmeasurementrange.Athighlatitudestheionosphericionsconsistonlyofprotons,butneartheequatoralowenergyheavyionpopulationisalsoobservedduringsome,butnotequatortransits.Inthisstudywewillpresentobservationsofthelowenergyionosphericionsinthesub-auroralregionsandbelowanaltitudeof1RJ.
Outflowofplasmawithoutremovalofmagneticflux:Whatistherealmagnetictopology?Vasyliūnas,V.M.,Max-Planck-InstitutfürSonnensystemforschung
Inthemagnetospheresofthegiantplanets,plasmaissuppliedpredominantlybysourcesthatliedeepwithinthedipolarmagneticfieldlineregionandislostultimatelybyflowoutintothesurroundingexteriorregion.Theoutwardtransportoftheplasmamustoccurwithoutremovalofmagneticflux;whenaplasmaelementcrossestheinterfacetothemagnetotailand/ormagnetosheath,themagneticfieldlinesthreadingtheelementmustbecomedisconnectedfromtheplanet'sdipole.Thisisaspecifictypeofmagneticreconnection,discussedalsoinsolarandterrestrialcontexts.Forouterplanetmagnetospheres,thesimplestmodelisasequenceoftopologicalchangeswidelyknownastheVasyliūnascycle.Thatthemagnetictopologyofthismodelisconceptuallypossiblehasnotbeenproved(incontrasttothetopologyofDungey'sopenmagnetospheremodel,whichcanbedemonstratedbyasimpleanalyticalmodel).IshowthatinfactthemagnetictopologyofboththepublishedVasyliūnascycleanditscounterpartsinothercontextspresupposesahiddensymmetryandissingular(non-generic):itrepresentsthecaseofnoasymmetry,whichisqualitativelydifferentfromthatofvanishinglysmallasymmetry.Withoutthesesymmetryassumptions,thevolumeoccupiedbyformerlyclosedfieldlinesthathavebecomedisconnectedisnotthecommonlyenvisagedplasmoidintwodimensionsbutathree-dimensionalquasi-toroidalstructureoftheDungeytype.Thecorrespondingsequenceofmagneticfieldchanges,whichallowsplasmatoflowoutwhilereturningmagneticfluxtotheplanet,preservesthemainqualitativefeaturesoftheoriginalVasyliūnascycle(inparticularthespatialdecouplingofreconnectionandplasmaoutflow)butnotitsspecifictopology.Possibleimplicationsforgiantplanetmagnetotailswillbediscussed.
103
![Page 104: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/104.jpg)
JunoObservationsofMagnetotailReconnectionatJupiterVogt,M.F.,BostonUniversityConnerney,J.E.P.,DiBraccio,G.A.,Gershman,D.J.,Clark,G.B.,Paranicas,C.,Kurth,W.S.,Ebert,R.W.andValek,P.
Magneticreconnectionisanimportantphysicalprocessthatallowsforthereleaseofmassandenergyfromaplanetarymagnetotail.AtJupiter,tailreconnectionisthoughttobedrivenbyaninternalmassloadingandreleaseprocesscalledtheVasyliunascyclewhichisexpectedtooccurwithatypical2-4dayrecurrenceperiod.AnalysisofmagneticfieldandenergeticparticledatafromtheGalileospacecrafthasshownevidenceofhundredsofreconnectioneventsoccurringinJupiter’smagnetotailandhasattemptedtocharacterizetheirproperties,includingthesize,recurrencetime,andlocationoftailreconnectionsignatures.Forexample,theGalileoobservationsestimatethatthemasslostbyplasmoidsisonlyasmallfractionofthemassinputfromIo,thoughthemasslossratecalculationsarepoorlyconstrained.HerewepresenttheresultsofaninitialsurveyofmagnetotailreconnectionsignaturesobservedwiththeJunospacecraft.ThenewJunoobservationscomplementtheGalileodatabyprovidingimprovedmeasurementsoftheplasmadensityandvelocity,whichiscriticalforconstrainingthemasslostbyplasmoids,andbyprovidingadditionalspatialcoverageinthemagnetotail.Takentogether,theGalileoandJunoobservationsshouldprovidenewinsightintothedriversofmagnetotailreconnectionanditsroleintheoveralltransportofmassandmagneticfluxinJupiter’smagnetosphere.
ElectrodynamicsinSaturn'sThermosphereVriesema,J.W.,LunarandPlanetaryLaboratoryKoskinen,T.T.andYelle,R.V.
Saturn'smagnetosphereisknowntobeelectrodynamicallycoupledtoitsthermosphere,especiallyinauroralregions,butlessisknownabouttheelectrodynamicsofthethermosphereatlowlatitudes.TowardthegoalofdevelopingamorecompleteunderstandingofelectrodynamicsinSaturn'supperatmosphere,weinvestigatetheeffectofequatorialwindsonSaturn'sionosphericwinddynamoatlowerandmiddlelatitudesusinganaxisymmetric,steady-statemodel.Asinputsforourmodel,wecalculateaone-dimensionalconductivityprofileandconstructatwo-dimensionalmodelwindprofilebasedonresultsfromageneralcirculationmodelbutwiththeadditionofanequatorialjet,whichweassumepersistsuptothelowerthermospherefromthetroposphere.Thismodelpredictscurrentdensitiesoftheorder10-9to10-7Am-2.Ourmodelalsopredictssubstantialresistive(Joule)heatingandiondrag,whichhavethepotentialtosignificantlyaltertheenergeticsandcirculationbalanceoftheupperatmosphere.
104
![Page 105: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/105.jpg)
OntheCharacteristicsofChargedDustinSaturn’sEquatorialIonosphere–ImplicationsfromCassiniRPWS/LPdataWahlund,J.-E.,SwedishInstituteofSpacePhysics(IRF)Vigren,E.,Morooka,M.W.,Hadid,L.Z.,Farrell,W.M.,Persoon,A.M.,Kurth,W.S.,Gurnett,D.A.,Mitchell,M.E.,Perry,D.G.WaiteJr.,J.H.,Moore,L.,Cravens,T.E.,Galand,M.,andNagy,A.F.
TheCassinispacecraftobservationsclosetoSaturnhaverevealedthat1-100nm-sizeddustgrainsprecipitatefromtheD-ringintotheatmosphere.RPWSLangmuirprobeionnumberdensitymeasurementssuggestthatthechargeddusthasaprofoundeffectontheionosphericstructure,enhancingtheionnumberdensitywellabovephotochemicalequilibriumlevels,whiletheelectronstendtobecomeattachedtothedustpopulation.WepresentmodelcalculationsofSaturn’sequatorialionosphereandincludetheeffectofchargeddustgrainsthatbreakdownintosmallergrains/clustersdeeperintheatmosphereatanaltitudeneartheionosphericpeak.ThemodelisconstrainedasfaraspossiblebyinputfromCassiniINMS,RPWSandINCA/CHEMSmeasurements,andthencomparedwithobservedelectronandionnumberdensitiesbyRPWS.Fromthesedust-ionospheremodelcalculationsitisclearthatalayerofsmallsinglychargedsub-nm-sizeddustgrainscanexplaintheRPWSLangmuirprobemeasurements.
Self-consistentmodelingofplanetaryelectrondynamicsWang,L.,PrincetonUniversityDong,C.F.,Bhattacharjee,A.,Raeder,J.,GermaschewskiK.,Hakim,A.H.
Electrons,particularlytheenergetic,suprathermalcomponentscouldplayimportantrolesinmagnetosphericdynamicsinmanyplanetarysystems.However,theinclusionoftheseeffectsintoglobal-scalemodelingofmagnetospheresystemshasnotbeeneasy.Weproposetousethemulti-fluidhigh-momentmodeltoaddressthisissue.Themodelevolvesanarbitrarynumberofelectronandionspecieswithdifferentcharge/massnumbers,and/orenergylevels,toaccountforthecomplexplasmacompositioninthemagnetospheres.Themodelcapturesnon-idealphysicsliketheHalleffectandanisotropic,non-gyrotropicpressureeffectsthatareimportantincontrollingthestrengthofreactiontoexternaldrivingsandthebalanceinaquasi-steadystate.WehavesuccessfullyappliedthemodeltothemagnetospheresofGanymedeandMercury,andtheresults,includingdata-modelcomparison,willbediscussedinthispresentation.Wewouldalsodiscussthecapabilitiesofthismodelinimprovingtheplanetarymagnetospheremodelingthatwewillutilizeinthefuturework.
105
![Page 106: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/106.jpg)
AngularSizeofIoMagneticFootprint’sMainAlfvènWingSpot:InCorrespondingtoSatellite’sLocationsWannawichian,S.,DepartmentofPhysicsandMaterialsScience,FacultyofScience,ChiangMaiUniversity,ChiangMai,ThailandJohnT.C.,JonathanD.N.
Satellitesinplanetarymagnetosphereareoftenaffectedbytheinteractionbetweenmagnetosphericplasmaandsatellites’atmospheres.Duetotheinteraction,pickedupcurrentstravelalongthemagneticfieldlinefrominteractionregiontowardtheplanet’sionosphere.ThesecurrentsclearlyconnectthevicinityofIotoJupiter’ionosphereviamagneticfieldlines.Inionosphere,spotemissionscanbedetectedattheendmagneticfieldline,whichisknownas“AuroralMagneticFootprint”.Io’smagneticfootprintisaprominentauroralfeature,whichlocatesfewdegreeslatitudelowerfromJupiter’smainauroralemission.CorrespondingtointeractionregionatIoapproximately1.5Ioradii,thesizeofIo’smagneticfootprintisexpectedtobeapproximately~100km.Inthisstudy,thesizeofthefootprints,especiallytheMainAlfvènwingspot(MAW),willbeanalyzedbasedonFUVimagingbyAdvancedCameraforSurveys(ACS)instrumentonHubbleSpaceTelescope(HST).TheimagesofJupiter’sauroralregionweretakenin1998,2000,2001,and2007duringHST’scampaigns.Fordifferentepochsofobservations,theangularsizesofIo’smagneticfootprintvariedwithgeneraltrend,inwhichseveralemissionpeaksweredetected.Thisresultcouldbeinterpretedtohavesomecorrelationwiththefootprintbrightness.AccordingtoinsituobservationsofplasmaenvironmentnearIo,temporalandspecialvariationsofJupitermagnetosphericplasmacouldbeoneofthefactorsthataffectthebrightnessandangularsizeofIo’smagneticfootprint.
PulsationcharacteristicsofJovianinfraredpolarauroraobservedbySubaruIRCSwithadaptiveopticsduringJuno’ssolarwindcampaignWatanabe,H.,TohokuUniversityKita,H.,Sakanoi,T.,Tao,C.,Kagitani,M.,Kasaba,Y.
Wereportthe~10minperiodiccharacteristicsofJovianinfrared(IR)aurorafoundinH3+
narrow-bandimaging(centeredat3.4um)ofSubaru8-mwithadaptiveopticson25May2016duringJuno’ssolarwindcampaign.Inpastobservations,noIRaurorahassignificantvariationsontimescaleslessthan30min.Theyareconsideredasstableover~90min[e.g.Stallardetal.2016].However,small-scaleandrapidvariationsmayexistinIRauroraconsideringthatthetimescaleofH3
+emissionis102-104sec[Taoal.,2013],especiallyinthepolarregionwhereperiodicultraviolet(UV)emissionswithtimescalesofafewsecondsorminuteshavebeenobserved.Inthisstudy,wecarriedoutthenarrow-bandimagingofJovianH3
+aurorawithIRCS(InfraredCameraandSpectrograph)attachedontheSubarutelescopeatMaunaKea,Hawaii,withthetimeresolutionof45-110sec.BytheassistofAdaptiveOpticsinstrument(AO188),wecanachievespatialresolutionof~0.1arcsec[Minowaetal.,2010].Themainovalwasstablybrightinthedawnside(SystemIII:~190-210deg)anddimontheduskside(S-IIIlongitude:~160-180deg,calledas‘discontinuity’inUVobservation).Twoorthreepolarpatcheswerealsoseenalongthemainoval.Theyweresub-corotatingandtheirintensitieswerevaryingapartfromeachother.Inparticular,apatchappearedin62-65deginlatitudeand172-182deginS-IIIlongitudewasclearlypulsatingwithanamplitudeof~20%andtheperiodof~10minwhichwasidentifiedbytheLomb-Scarglemethod.SincethetimescaleofH3
+dynamictransportordiffusionisexpectedas104-105sec[Taoetal.,2013],thepulsatingcannotbeexplainedbythem.UsingtheauroralemissionmodelbyTaoetal.[2011],weconfirmedthattheH3
+emissionintensityiswellresponsibletothe~10minvariationofauroralelectronflux.Thisestimationisconsistentwiththeobservation.
106
![Page 107: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/107.jpg)
ACompendiumoftheSaturn-TitanInteractionasObservedwithEnergeticNeutralAtoms(ENAs)fromCassiniMIMI-INCAWestlake,J.H.,JHU/APLMitchell,D.G.;Brandt,P.C.
Forthe127TitanflybysofCassinitheINCAENAcamera[Krimigisetal.,2004]hasobservedthemoon-magnetosphereinteractionusingchargeexchangeofthemagnetosphericionswiththedenseneutralatmosphereofTitanandproduced105flybysworthofdata.FromtheseTitanflybysthereexistsmultiplevantagepointsforENAimagingofthemoon-magnetosphereinteractionrevealingintriguingENAmorphologyrelatedtothemagneticfield[Wulmsetal.2010],andtemporalfeatures[e.g.Mitchelletal,2005].DuetothenatureoftheinputplasmaanditspitchangledistributionandtheshadowingofENAsfromTitan’satmosphereitiscrucialtoutilizethemultitudeofvantagepointstofullyunderstandthisinteraction.InthispaperwepresentanupdatedcompilationoftheINCAENAobservationsatTitanshowingtheflybysandspecifictimeswheregood,cleanENAobservationsareavailableaswellaspointingoutspecificfeaturesintheENAobservationssuchasburstsofheavyionENAemissionsanduniquetemporalfeatures.ThislistofobservationtimesandfeaturesisthenusedinconjunctionwiththeupstreamconditionsandfieldconfigurationsfromtheworkofSimonetal.2010,2013,Rymeretal.2009,andGarnieretal.2010tounderstandthecomplexinterplayoftheplasma,magneticfields,andparticleenvironments.ThedataissortedbyvantagepointandflybyconditiontounderstandhowtheplasmaandparticleenvironmentvaryatTitan.
ForwardModelingMultipleHeavyIonSpeciesinJADEDataWilson,R.J.,LASP,CUBagenal,F.,Valek,P.W.,Allegrini,F.,Ebert,R.W.,Kim,T.K.,Ranquist,D.A.,Thomsen,M.F.
Jupiter'smagnetosphereishugeandtypicallyhasasizebetween~60to~120RJ(1RJ=1jovianradius),yetpastmissionshaveonlybeenabletoexplorethethermalplasmaoutto~30RJwithsparsecoverage.TheVoyagerseachhadaflybybutwere3-axisstabilizedanddidnotalwayspointinthedirectionofplasmaflow[Bagenal+,2017].TheGalileoplasmaspectrometer(GLL/PLS)wasonanorbitingspinningplatform,butwasnotverysensitiveandduetoagreatlyreduceddatarate,returnedonlyasubsetofnon-continuousenergystepsperspin[Bagenal,Wilsonetal.,2016].Juno'sJADEisasensitiveplasmainstrument,onaspinningplatformabletoviewallskyoverconsecutiveenergies.Junohas53-dayorbitswithapojovesof112RJ,allowingexplorationofthemiddle/outerjovianmagnetosphereinregionsunexploredbypreviousthermalplasmainstruments.
JunoJADEproducesdirectional'species'data,whereitdividesupthetime-of-flight(TOF)datasetinto3classes(H+,lights,heavies).NumericalmomentsarefasttocomputeandareroutinelymadebytheJADEteamtoobtainadensity,n,temperature(s),T,andvelocity,V,ofeachclassseparately,butrequireasingularmass/charge(m/q)foreachclass.TheheaviesconsistprimarilyofO+&S++(thesamem/q,whichcannotbeseparatedinthespeciesdataset)plusotherspecies,allofwhichmustbeassumedtohavethesamem/q(e.g.24/1.5).Howeverwithforwardmodelingwemayfitasmanyionspeciesaspresent(intheTOFdata)simultaneously(i.e.separatingO+&S++)tothetotalJADEspeciesdata,assumingasharedV,butallowingnandTtovarybyspecies.Theprocessiscomputationallyveryexpensive;requiringtuningbyhandtofittheparticularsofthedataset,andthispresentationshowstheinitialstagesofthiswork.WehopetowinproposalstofundafullsurveyoftheplasmasheetbyJADEtomeasuretheflowofmassandenergythroughthejovianmagnetosphere.
107
![Page 108: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/108.jpg)
TheeffectofwaveparticleinteractionsonelectronsclosetoSaturnWoodfield,E.E.,BritishAntarcticSurveyHorne,R.B.,Glauert,S.A.,Menietti,J.D.,Shprits,Y.Y.
TheGrandFinaleorbitsofCassinigiveusagreatopportunitytoinvestigatetheeffectsofwavesonparticlesveryclosetotheplanet.PreviousworkhasshownthatZ-modewavesaccelerateelectronsstronglybetweentheA-ringandtheorbitofEnceladusandthatwhistlermodechorusisalsoveryeffectiveatacceleratingelectronsattheEarthandJupiter.ThenewdatafromCassinishowsthatZ-modeandwhistlermodewaveshavebeenobservedeveninsidethemainrings.InthisstudyweinvestigatetheeffectsofthewavesobservedbyCassinionelectronsofvariousenergieslookingforaccelerationandscatteringregimesveryclosetotheplanet.WealsotakeafirstlookattheeffectsofwhistlermodewavesoutsideofthemainringsbutinsideoftheorbitofEnceladus,intheregionwhereZ-modewaveshavepreviouslybeenshowntostronglyaccelerateelectrons.
3DJovianMagnetosphere-Ionosphere-Thermosphere(MIT)Yates,J.N.,EuropeanSpaceAgencyRay,L.C.,Achilleos,N.
Jupiter’supperatmospherictemperatureisconsiderablyhigherthanthatpredictedbySolarExtremeUltraviolet(EUV)heatingalone.Simulationsincorporatingmagnetosphere-ionospherecouplingeffectsintogeneralcirculationmodelshave,todate,struggledtoreproducetheobservedatmospherictemperaturesundersimplifyingassumptionssuchasazimuthalsymmetryandaspin-aligneddipolemagneticfield.Herewepresentthedevelopmentofafullthree-dimensionalthermospheremodelcoupledinbothhemispherestoanaxisymmetricmagnetospheremodel.Thisnewcoupledmodelisbasedonthetwo-dimensionalMITmodelpresentedinYatesetal.,2014.Thiscoupledmodelisacriticalsteptowardstothedevelopmentofafullycoupled3DMITmodel.Wediscussandcomparetheresultingthermosphericflows,energybalanceandMIcouplingcurrentstothosepresentedinprevious2DMITmodelsandobservationswhereavailable.
108
![Page 109: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/109.jpg)
AnSLS5longitudesystembasedontherotationalmodulationofSaturnradioemissionsYe,S.-Y.,TheUniversityofIowaFischer,G.,Kurth,W.S.,Menietti,J.D.,Gurnett,D.A.
DespitetheaxisymmetryofSaturn’sinternalfield,SaturnradioemissionslikeSaturnkilometricradiation(SKR)aremodulatedduetoplanetaryrotation.WiththecompletionofCassinimissioninSeptember2017,wenowhaveover14yearsofobservationofSaturnradioemissions,roughlyfromsouthernsolsticetonorthernsolstice.Inthisstudy,weextendtheSLS4longitudesystemtotheendoftheCassinimissionusingaphasetracingmethod.ThenewSaturnlongitudesystem(SLS5)organizestheSKRmaximaaround0°longitudeinbothnorthernandsouthernhemispheresandcanbeusedtoorganizeotherphenomenaobservedinSaturn’smagnetosphere.
PlasmaandenergytransportinJupiter’sinnermagnetosphereasdeducedfromHisakiobservationYoshioka,K.,TheUniversityofTokyoTsuchiya,F.,Kagitani,M.,Kimura,T.,Murakami,G.,Yoshikawa,I.,Yamazaki,A.,Hikida,R.,Fujimoto,M.
Sinceitslaunchin2013,theExtremeUltravioletspectrometerEXCEEDonboardtheHisakispacecraftisobservingJupiter’sauroraandtheIoplasmatoruscontinuously.ThesulfurandoxygenionswhicharethemaincomponentsoftheIoplasmatorusemitlinesthroughtheimpactexcitationbytheambientelectrons.ThespectralresolutionofEXCEEDishighenoughtodistinguishthoselines.Thentheiondensities,electrondensities,andelectrontemperaturecanbededucedusingthesocalledspectraldiagnosismethod.Todiscusstheoutwardtransporttimescaleofplasmas,energyvalanceinsidethetorus,andneutralsourceratefromthosededucedparameters,weadoptthephysicalchemistrymodelasdescribedinDelamereetal.[2003].Inthisstudy,wecomparetheplasmatransporttimescale(velocity)withvariousenvironmentalconditionssuchasJupiter’sSystemIIIrotation,Io’srotation,Io’svolcanicactivity,andsolarwindcondition.
109
![Page 110: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/110.jpg)
JupiterradioemissioninducedbyGanymedeandconsequencesfortheradiodetectionofexoplanetsZarka,P.,LESIA&USN,Obs.Paris/CNRS/PSL,Meudon,FranceSoaresMarques,M.,Louis,C.,Ryabov,V.B.,Lamy,L.,Echer,E.,Cecconi,B.
Radiodetectionofexoplanetsshallopenauniquewindowontheirmagneticfield,rotation,andplasmaenvironment.Inoursolarsystem,Jupiter’sdecametricemissionisasintenseasSolarradiobursts,butneitherisdetectablebeyond~0.1pcwithlargepresent-daylow-frequencyradiotelescopes.Thepossibleexistenceofmuchstrongerplanetaryradioemitterswasdeducedfromscalinglawsbuiltfromplanetaryradiosourcesinoursolarsystem,wheretheprimaryengineoftheradioemissionisthekineticormagneticpowerinputfromthesolarwindtothemagnetosphere(hencenamedradio-kineticandradio-magneticscalinglaws).HerewepresentthefirstquantitativestudyoftheGanymede-Jupiterradioemission,recentlydetectedunambiguouslybyanalysinga26-yeardatabaseofdecametricobservationsofJupiter.Focussingonitsenergetics,wecompareittotheIo-Jupiteremission.WeshowthatinspiteofthedifferentinteractionsofthesemoonswithJupiter’smagnetosphere(primarilyviaAlfvénwavesforIoandmagneticreconnectionforGanymede),theirinducedradiopowersareinthesameratioasthemagneticpowerinputthattheyinterceptfromthemagnetosphere.Moregenerallyauroral,Io-inducedandGanymede-inducedradioemissionsallfitaradio-magneticscalinglawthatpredictsstrong–potentiallydetectable–radioemissionsforhotjupiters.ThestatisticsofGanymede-Jupiterradioemissiondurationsalsobringssomelightontheinteractionofthesetwobodiesviamagneticreconnection.
MagnetopauseDynamicsfrom3DHallMHD-EPICSimulationsofGanymede`sMagnetosphereZhou,Hongyang,UniversityofMichiganToth,Gabor;Jia,Xianzhe
Thelargestmooninthesolarsystem,Ganymede,isalsotheonlymoonknowntopossessastrongintrinsicmagneticfieldandacorrespondingmagnetosphere.Anewmodelingtoolemployingtheimplicitparticle-in-cell(PIC)codeiPIC3DembeddedintotheBATS-R-USHallmagnetohydrodynamic(MHD)modelisappliedtosimulatethemagnetosphericstructureanddynamicsofGanymede.ImprovementsofthenewMHD-EPICmodelincludeaself-consistentlycoupledresistivebodyrepresentingtheelectricalpropertiesofthemoon’sinterior,improvedinnerboundaryconditions,andtherecentlyimplementedenergy-conservingschemeforiPIC3D.OurnewmodelissuccessfullyvalidatedforallsixGalileoflybysbasedoncomparisonsofthemagneticfield.AsmagneticreconnectionisthemaindriverofGanymede’smagnetosphericdynamics,wefocusourpresentstudyonthemagnetopausereconnection,whichisresolvedbythekineticcodeiPIC3Dinoursimulations.Wefindthatundersteadyupstreamconditions,magnetopausereconnectionoccursinanon-steadymanner.Asaresult,fluxtransferevents(FTEs)formonthemagnetopauseproducingspatialandtemporalvariationsinplasmaandfieldproperties.Wealsodeterminetheoccurrencerateandspatialdistributionofreconnectionsitesandquantifytheglobalreconnectionrateatthemagnetopauseinoursimulations.BycomparingmodelresultsfromdifferentGalileoflybys,weareabletogaininsightsintohowmagneticreconnectionandFTEformationatGanymedevarydependingontheupstreamconditions,especiallytheAlfvenicMachnumberandthemagneticshearangle.Whilethemagnetopausereconnectionappearsintermittentinallofoursimulations,noobviousperiodicityisfound,potentiallyindicatingachaoticenergy-cascadingsystem.
110
![Page 111: Magnetospheres of the Outer Planets - lasp.colorado.edulasp.colorado.edu/home/mop/files/2018/07/Mop2018-Program-Online-PDF-A... · Tomoki Kimura Emmanual Chane Tamas Gombosi Masaki](https://reader030.vdocument.in/reader030/viewer/2022040420/5e062a6109ddc91e77152d9e/html5/thumbnails/111.jpg)
Index
Agiwal 11 Gladstone 38 Louis 67 Sergis 94Alexeev 11 Griton 38 Lysak 68 Sinclair 95Allegrini 12 Grodent 39 Magalhaes 68 Smith 95
Allen 12 Guio 39 Manners 69 Song 96 Andrews 13 Hadid 40 Martin 69, 70 Sorba 96Arakawa 13 Haggerty 40 Masters 70, 71 Soto-Chavez 97
Arridge 14 Hamil 41 Mauk 71 Southwood 97Azari 14 Hardy 41 Menietti 72 Spencer 98
Bader 15 Harris 42 Misawa 72 Staniland 98Badman 15 Hendrix 42 Mitchell 73 Stephens 99Bagenal 16 Heuer 43 Morgenthaler 73 Styczinski 99
Bard 17 Higgins 43,44 Morooka 74 Sulaiman 100Becker 17 Hikida 44 Munoz 74 Szalay 100
Bergman 18 Hinton 45 Mura 75 Tao 101Berland 18 Horanyi 45 Murakami 76 Thomsen 101Bertucci 19 Hospodarsky 46 Nakamura 76, 77 Trafton 102Blöcker 19 Houston 46 Nenon 78 Travnicek 102
Bonfond 20 Hsu 47 Nerney 78 Valek 103Bradley 20 Hue 47 Neupane 79 Vasyliūnas 103
Brown 21 Hunt 48 Nichols 79 Vogt 104Bunce 21 Huscher 48 O'Donoghue 80 Vriesema 104
Burkholder 22 Huybrighs 49 Palmaerts 80 Wahlund 105Burton 22 Imai, K 49, 50 Parunakian 81 Wang 105Cao, H 23 Imai, M 50 Paty 81 Wannawichian 106Cao, X 23 Jackman 51 Perry 82 Watanabe 106Carlton 24 Jasinski 51, 52 Phipps 82 Westlake 107
Carnielli 24 Jia 52, 53 Píša 83 Wilson 107Cassidy 25 Kammer 53 Ponce 83 Woodfield 108Cecconi 25 Kane 54 Pontius 84 Yates 108
Chané 26 Kasaba 55 Poppe 84 Ye 109Clark 26 Katoh 55 Prangé 85 Yoshioka 109
Clarke 27 Khurana 56 Provan 85 Zarka 110Coffin 27 Kim 56 Pryor 86 Zhou 110Collier 28 Kimura 57 Ranquist 86
Collinson 28 Kinrade 57 Rathbun 87Connerney 29 Kita 58 Ray 87
Crary 29, 30 Kivelson 58, 59 Retherford 88Cravens 30 Koga 60 Roth 88, 89
Damiano 31 Kollmann 61 Roussos 89Davies 31 Korth 62 Rutala 90
Delamere 32 Koskinen 62 Rymer 90Dols 32 Krupp 63 Sakanoi 91
Dunn 33,34 Kurth 63 Santos-Costa 91Ebert 35 Lamy 64 Sarkango 92Elliott 36 Lee-Payne 65 Saur 92
Farrell 36 Liuzzo 65, 66 Sawyer 93Fischer 37 Lorch 66 Schmidt 93Gérard 37 Louarn 67 Schneider 94
111