universal processes in neutral media roger smith chapman meeting on universal processes savannah,...

Universal Processes in Neutral Media

Roger Smith

Chapman Meeting on Universal Processes

Savannah, Georgia November 2008

AGU Chapman Meeting on Universal Processes 11/2008

2

Contents of Talk

• Big picture view on universal processes

• Processes in plasma and neutral media

• Examples of universal processes in neutral and mixed media

• Need for a balanced approach developing Heliophysics as a new scientific discipline.


3

Big Picture of universal processes

• Galactic view of heliosphere shows the sun with surrounding plasma envelope and planets.

• Expect universal processes to be found throughout the heliosphere.

• Universal Heliophysical Processes include those in all regimes of the heliosphere. Hence in sun, solar wind, comets and planets.


4


5

E E S S E

E

E E E

E E E

S E E E E

E S E

E

E

CM

E and flares

Solar W

ind

Solar C

ycle

Granulation

Cosm

ic Ray

Modulation

Irradiation

Reconnection

Particle Acceleration

Shocks and Waves

Dynamo

Turbulence, Convection

Multiscale Structures

Energy storage, release

Radiative Transfer

PhenomenaU

niversal Processes

S = Speculative

E = Established

6

Solar Dynamo

Magnetic Flux EmergenceSunspots, Active Regions

Electromagnetic Radiation

Solar Wind

Flares:ReconnectionElectromagnetic flashesEnergetic Particles

CMEs:Mass ejectionMagnetic flash ejectionEnergetic Particles

CME Shock Formation

CIR Shock Formation

Magnetic Cloud

Pressure PulseSEPs

Geomagnetic Storms:Aurora, radiation belts, ring current, ionospheric effects.

Climate effects:Thermosphere, mesosphere, stratosphere, troposphere.

Slide by Gopalswamy


7

General importance of universal processes in neutral media

• Major receptors of solar energy are found in the planets, asteroids, comets and other massive bodies.

• Apart from the sun, much of the mass of the heliosphere is found in uncharged objects such as those listed above.


8

Examples of universal processes involving neutral media

• Turbulence


9

Turbulence in Atmospheres

• Transport of energy and momentum by gravity waves, establishing turbulent regions in upper atmospheres.

• Micro-turbulence in the atmospheric boundary layer.– Coupling heat from the ground into the

atmosphere (scintillation observed)– Raising dust and sand leading to mass

transport and modulation of solar radiation


10


• Acoustic gravity waves


11

Extensive NLC Layer(5.5 hours duration)


12

Unique event:• Large intensity perturbation I/I: ~ 50%, • Horizontal wavelengthH: 27 km.• High intrinsic phase speed: 80m/s• Short intrinsic period: 5.6 mins.• Formation of turbulent-like features.• Instability duration: 40 mins.

Small-Scale Wave Breaking Into “Turbulence”

Large amplitude Momentum flux: ~900 m2/s2 Mean-flow acceleration: ~ 80m/s in < 1 hr.

Japan

For a breaking wave, the momentum flux FM can be estimated by:

)(2

Ucm

kFM

(Fritts et al., 2002)

(Yamada, et al, 2001)

16:40 UT

16:52 UT


13

Gravity Waves on:

Mars Global Surveyor

MarMars !s !

Lee Waves at mid-latitudes and polar regions. Wavelength ~ 50 km


14


• Ionization and recombination


15

Equatorial Plasma Fountain and Anomaly Process


16


17

Rayleigh-Taylor Instability Mechanism


18


19


• Cloud condensation


20

Formation of clouds

• Cloud layers absorb and scatter light reducing solar illumination and heating.

• Turbulence enhanced dust clouds in desert areas on Earth and Mars.

• Cloud nucleation and droplet growth not fully represented in climate and weather forecasting codes. Major source of uncertainty for planets and moons with atmospheres, for example Earth, Venus, Mars, Jupiter.


21


• Aurora


22

Jupiter’s Three Auroral Processes

• The main oval appears driven by currents resulting from the breakdown in corotation of internal plasma.• The satellite footprints are produced by their interactions with Jupiter’s magnetic field.• The polar emissions map to the outer magnetosphere, and these interactions are not yet well understood.


23

Jupiter’s aurora have been imaged by HST since the early 1990’s with high sensitivity and resolution. A campaign of imaging during the Cassini flyby in Dec. 2000 / Jan. 2001 was successful but short…

HST/WFPC2 HST/STIS

Jupiter


24


• Dusty plasma processes


25


26


• Planetary outflow


27


• Loading of interplanetary field lines


28


29

Mid

dle

an

d lo

wer a

tmo

sp

here

s

Ion

osp

here

s

therm

osp

here

s

Co

mets

CM

E a

nd

flare

s

So

lar W

ind

So

lar C

ycle

Gra

nu

latio

n

Co

sm

ic R

ay M

od

ula

tion

Irrad

iatio

n

E = established, S = speculative

E E S S E ReconnectionE E Particle AccelerationE E E E Shocks

E E E E E WavesE E E E Dynamo

E S E E E E Turbulence, ConvectionE E S E Multiscale structuresE E E Energy Storage, release

E E E Radiative TransferE Ionization and Recombination

E E Dusty Plasma processesE Cloud condensation

E E E Heavy ion outflow to the solar windE E Planetary aurora

Phenomena

Un

iversa

l Pro

cesse

s


30

Conclusion: universal processes involving neutral media

• Turbulence• Ionization and recombination• Dusty plasma processes• Planetary outflow• Loading of interplanetary field lines• Acoustic gravity waves• Cloud condensation• Aurora

universal processes in neutral media roger smith chapman meeting on universal processes savannah,...

Documents

universal processes

universal processes

agu chapman meeting

neutral media turbulence

established slide

gopalswamy slide

hours duration slide

waves dynamo turbulence