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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.
AGU Chapman Meeting on Universal Processes 11/2008
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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.
AGU Chapman Meeting on Universal Processes 11/2008
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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
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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
AGU Chapman Meeting on Universal Processes 11/2008
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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.
AGU Chapman Meeting on Universal Processes 11/2008
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Examples of universal processes involving neutral media
• Turbulence
AGU Chapman Meeting on Universal Processes 11/2008
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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
AGU Chapman Meeting on Universal Processes 11/2008
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Examples of universal processes involving neutral media
• Acoustic gravity waves
AGU Chapman Meeting on Universal Processes 11/2008
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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
AGU Chapman Meeting on Universal Processes 11/2008
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Gravity Waves on:
Mars Global Surveyor
MarMars !s !
Lee Waves at mid-latitudes and polar regions. Wavelength ~ 50 km
AGU Chapman Meeting on Universal Processes 11/2008
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Examples of universal processes involving neutral media
• Ionization and recombination
AGU Chapman Meeting on Universal Processes 11/2008
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Equatorial Plasma Fountain and Anomaly Process
AGU Chapman Meeting on Universal Processes 11/2008
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Examples of universal processes involving neutral media
• Cloud condensation
AGU Chapman Meeting on Universal Processes 11/2008
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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.
AGU Chapman Meeting on Universal Processes 11/2008
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Examples of universal processes involving neutral media
• Aurora
AGU Chapman Meeting on Universal Processes 11/2008
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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.
AGU Chapman Meeting on Universal Processes 11/2008
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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
AGU Chapman Meeting on Universal Processes 11/2008
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Examples of universal processes involving neutral media
• Dusty plasma processes
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Examples of universal processes involving neutral media
• Planetary outflow
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Examples of universal processes involving neutral media
• Loading of interplanetary field lines
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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