ulf wave modelling with a motive: effects on energetic paritcles mary hudson, scot elkington, brian...
Post on 20-Dec-2015
214 views
TRANSCRIPT
ULF Wave Modelling With A ULF Wave Modelling With A Motive: Effects on Energetic Motive: Effects on Energetic
ParitclesParitcles
Mary Hudson, Scot Elkington, Brian Kress, Kara Perry, John Lyon, Mike Wiltberger
ULF Wave-Relativistic Electron ULF Wave-Relativistic Electron CorrelationCorrelation
Rostoker et al., GRL, 1998
Toroidal and Polodial ModesToroidal and Polodial Modes
Hughes, Solar Wind Sources of Magnetospheric ULF Waves, AGU, 1994
CRRES Poloidal and Toriodal ULF Wave B Components
Hudson et al., Annales. Geophys., 2004
CRRES 18 degree inclination, 6.3 RE apogee, July 90 – Oct 91
CRRES Occurrence Rates of CRRES Occurrence Rates of Poloidal and Toroidal ULF WavesPoloidal and Toroidal ULF Waves
Hudson et al., Annales Geophys., 2004
AMPTE CCE Occurrence Rates Of AMPTE CCE Occurrence Rates Of Toroidal Mode Toroidal Mode
9 RE apogeeTakahashi et al., JGR, 2002
AMPTE IRM Occurrence Rates Of AMPTE IRM Occurrence Rates Of Poloidal/Compressional ModePoloidal/Compressional Mode
Anderson et al., JGR 1990
Mathie & Mann JGR 2000
Mathie & Mann 2000 JGR
Groundbased Magnetometer ULF Wave Studies
Pc5 Correlation with Solar Wind Pc5 Correlation with Solar Wind Speed and Relativistic Electrons Speed and Relativistic Electrons
Mann et al., JASTP, 2004
Convective Growth of Convective Growth of Magnetopause K-H WavesMagnetopause K-H Waves
Miura, JGR, 1992
Direct Coupling of Solar Wind ULF WavesDirect Coupling of Solar Wind ULF Waves
Kepko et al., GRL, 2002
Transmitting ULF Wave Power Into Transmitting ULF Wave Power Into Magnetosphere via Fast ModeMagnetosphere via Fast Mode
Structure of Externally Driven FLRsStructure of Externally Driven FLRs
Linear dipoleMHD simulation
Proehl et al., JGR 2002
δv ~ δE/B_0
Parallel Mode StructureParallel Mode Structure
Poloidal mL=1/3
Global LFM-MHD Simulations Global LFM-MHD Simulations of Magnetosphereof Magnetosphere
Solar wind Solar wind measurements made measurements made by satellite at L1, or by satellite at L1, or CME-solar wind CME-solar wind coupled MHD codes coupled MHD codes
Ideal MHD equations are Ideal MHD equations are solved on a solved on a computational grid to computational grid to simulate the response simulate the response of the magnetosphereof the magnetosphere
Goodrich et al. ‘98
L dependence of Ephi powerL dependence of Ephi power
Elkington, S. R., M. Wiltberger, A. A. Chan, and D. N. Baker, J. Atmos. Solar Terr. Phys., 66, 1371, 2004.
0.558-15 mHz
Azimuthal Distribution of P(Ephi)Azimuthal Distribution of P(Ephi)
Azimuthal Distribution of P(Ephi)Azimuthal Distribution of P(Ephi)
Azimuthal Mode Number from MHD Azimuthal Mode Number from MHD Simulations and Ground MagnetometersSimulations and Ground Magnetometers
Mathie & Mann, JGR, 2000
Sept 98 storm MHD (Ephi) wave power in 0.14-15 mHz, low m modes
Frequency DependenceFrequency Dependence
Bloom, R. M. and H. J. Singer, JGR, 100, 14943, 1995.
Convective Growth of Convective Growth of Magnetopause K-H WavesMagnetopause K-H Waves
K-H Shear-Driven InstabilityK-H Shear-Driven Instability
Direct Coupling of Solar Wind ULF WavesDirect Coupling of Solar Wind ULF Waves
Kepko et al., GRL, 2002
3 MHz Solar Wind Pulsations3 MHz Solar Wind Pulsations
SW Density Driven PulsationsSW Density Driven Pulsations
Test Particle Simulations of Test Particle Simulations of Radiation BeltsRadiation Belts
2D: Drift motion of electrons 2D: Drift motion of electrons and ions in the equatorial and ions in the equatorial plane is followed using time-plane is followed using time-varying electric and magnetic varying electric and magnetic fields from global MHD fields from global MHD simulationsimulation
3D: Bounce and drift motion 3D: Bounce and drift motion of guiding center electrons in of guiding center electrons in MHD fields; gyro, bounce and MHD fields; gyro, bounce and drift motion of Solar Energetic drift motion of Solar Energetic Particles (el, protons, Fe)Particles (el, protons, Fe)
Solar Energetic Particle (SEP) cutoffs calculated using MHD fields
MHD Fields Injection of RadBelt MHD Fields Injection of RadBelt ElectronsElectrons
Radiation Belt Electron Energization Radiation Belt Electron Energization Processes Conserving First InvariantProcesses Conserving First Invariant
Particles can be Particles can be energized by: energized by:
1)1)ConvectionConvection: steady, : steady, or substorm and or substorm and storm-enhancedstorm-enhanced
2)2)Diffusion*Diffusion*: : convection E convection E fluctuations, ULF wave fluctuations, ULF wave δE and δBδE and δB δE δE enhance diffusionenhance diffusion
3) 3) Drift time scale Drift time scale injection injection (Mar 91)(Mar 91)
a)Falthammar, JGR, 1965;b)Elkington et al., JGR, 2003
*
Diffusion Rates vs. L Diffusion Rates vs. L
Radial diffusion Radial diffusion rates in model rates in model ULF wave fieldsULF wave fields
D_LL ~ D_LL ~ LLNN
Falthammar, 1965 N=6, 10Falthammar, 1965 N=6, 10 Elkington et al., 2003Elkington et al., 2003 N=11N=11
Selesnick et al., 97, 2000 N=12Selesnick et al., 97, 2000 N=12
Perry et al., JGR, 2005, N=6, 18Perry et al., JGR, 2005, N=6, 18
Perry includes δEφ, δBr, δB//, freq Perry includes δEφ, δBr, δB//, freq and L-dependent Powerand L-dependent Power
Braughtigam & Albert, 2000, N=6, 10
MHD-Driven Phase Space DensityMHD-Driven Phase Space Density
AE8 Max-Initialized, Sept 98 Storm Fei et al., 2005
Drift Time Scale Injection from SSC’sDrift Time Scale Injection from SSC’s
Blake et al., 2005
EE in equatorial plane from MHD simulation of March 24, 1991 in equatorial plane from MHD simulation of March 24, 1991
CME-interplanetary shock compression of magnetopause.CME-interplanetary shock compression of magnetopause.
E x B transport of ring of radiation belt electrons inward E x B transport of ring of radiation belt electrons inward
by inductive by inductive EE due to magnetopause compression dBz/dt. due to magnetopause compression dBz/dt.
MHD-Guiding Center SimulationMHD-Guiding Center Simulation
Elkington et al., JASTP, 2002; 2004
Equatorial Plane Proton MHD Guiding Center Simulation
Hudson et al., JGR, 1997March 24, 91 event
Average Count Rate of 10-20 MeV Average Count Rate of 10-20 MeV Electrons Mirroring at SAMPEXElectrons Mirroring at SAMPEX
Solar Proton Trapping Nov 01Solar Proton Trapping Nov 01
New belt example: 24 Nov 2001New belt example: 24 Nov 2001
Clear trapping of solar particles - no other source of heavy ions possible
Mazur et al., SHINE mtg, 2004
Solar Energetic Particle AccessSolar Energetic Particle Access
Summary of ‘ULF Wave’ Effects on Summary of ‘ULF Wave’ Effects on Energetic ParticlesEnergetic Particles
Electrons interact diffusively with ULF Electrons interact diffusively with ULF waves with f ~ electron drift period while waves with f ~ electron drift period while conserving first invariantconserving first invariant
Large amplitude distortion of Large amplitude distortion of magnetopause launches magnetosonic magnetopause launches magnetosonic impulse outside range of linear ULF wave impulse outside range of linear ULF wave models, drift time scale injection of MeV models, drift time scale injection of MeV electrons and protons (electrons unusual)electrons and protons (electrons unusual)
Solar energetic particles trapped on drift Solar energetic particles trapped on drift time scale, stay trapped as long as 1time scale, stay trapped as long as 1stst invariant conserved (Young et al., 2002)invariant conserved (Young et al., 2002)
Higher Frequency Wave Mode Higher Frequency Wave Mode EffectsEffects
Other, 1Other, 1stst invariant invariant violating processes violating processes responsible for responsible for energy/momentum energy/momentum diffusion and pitch diffusion and pitch angle diffusion at angle diffusion at fixed L (VLF/ELF)fixed L (VLF/ELF)
Summers and Ma, JGR, 2000
Externally and Internally Excited Pc5 (mHz) ULF Waves: low and high m
Field Line ResonanceField Line Resonance
Dawn-Dusk Assymmetry in Dawn-Dusk Assymmetry in Toroidal Mode ULF Wave PowerToroidal Mode ULF Wave Power
Duskside B-compression affects K-H instability threshold velocity shear (Lee et al., JGR, 1981)
Sharper dawn-side radial gradient affects ionospheric screening (Glassmeir & Stellmacher, JGR, 2000)
Compressed (solid) vs. dipole (dashed) diffusion coefficients
Perry et al., JGR, 2005