ARTEMIS Science Working Team Meeting9/14-16/2011 Jasper S. Halekas Space Sciences Laboratory...
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Transcript of ARTEMIS Science Working Team Meeting9/14-16/2011 Jasper S. Halekas Space Sciences Laboratory...
ARTEMIS Science Working Team Meeting 9/14-16/2011
LUNAR PRECURSOR EFFECTS IN THE TERRESTRIAL MAGNETOSPHERE AND SOLAR WINDJasper S. HalekasSpace Sciences LaboratoryUniversity of California, Berkeley
The Lunar Space Plasma Environment: Pre-ARTEMIS
Precursor Effects in the Terrestrial Magnetosphere
All Electrons
Upgoing e- (0-15°)
Downgoing e- (165-180°)
EFI FFT
SCM FFT
B Wavelets
B Field
fpfce
fci
fpfce
Spin Tone
EFI Background
Free Energy Sources: Reflected Electrons in Magnetosphere
Loss Cone
Beam
Beam + Loss Cone:Produced By CombinedMagnetic & ElectrostaticEffects Near Surface
DownwardElectric Field
Plasma Electrons Follow Magnetic Field Linesand Reflect from E & B
Secondary ElectronsAccelerated Upward
E = - U
Δ
Converging Magnetic Field Lines above Crustal Magnetic Fields
Polarization Properties
Coherent
Parallel-Propagating
Right-Handed
• Wave properties all consistent with parallel-propagating whistlers coming down the magnetic field line towards the Moon
NarrowbandWaves propagating anti-parallel to field
EXB
EB
B0
Instability Conditions
EFI
SCW
Reduced DistributionFunctionWhistler Mode: ω/k, (ωce-ω)/k
Streaming instabilities where df/dv|| positive
Whistlers correlate with edges of loss cone: i.e. df/dvperp positive
Ions in the Mix?• Waves near fci modulate both the electron beam and the whistlers• Possible sources: Electron beam, shadowed ion distributions, bi-ion streaming
FGM Wavelets
Loss Cone Modulated
Electron Beam Modulated
Whistlers ModulatedProton & HeliumCyclotron Frequencies
ICWs?
Precursor Effects in the Solar Wind
IonsUpgoing e- (0-15°)
Downgoing e- (165-180°)
EFI FFT
SCM FFT
B Wavelets
B Field
SZA of SurfaceConnection
Fitzenreiter et al., 1990
Solar
Wind
Free Energy Sources: Reflected Electrons in Solar Wind
Generalized obstacle with magnetic fieldgradient and/or electrostatic potential gradient
MagneticField
ConvectionElectric Field
Electron Trajectory
Adiabatic Reflection in dHT Frame Gives you “Ears” in Solar Wind Frame
Whistler Cyclotron Resonance Conditions
EFI
SCW
Reduced DistributionFunction
(ωce-ω)/k : ω, k on whistler branch
Ion Observations
P2 Ions
P1 Ions
P1 Reduced Dist. Funct.
P1 Power Spectrum
P1 Propagation
P1 Ellipticity
Parallel-Propagating
RH, LH
Foreshock Ions
Reflected Protons
Free Energy Sources: Reflection From Crustal Magnetic Fields
Reflected Proton FluxesLue et al., 2010
Reflected ProtonsFollow PickupIon Trajectories
Sol
ar W
ind
GyratingProtons
Distribution Near Cycloid “Cusp”
IMF
SW
Pickup Ion Trajectories
Surface Crustal Magnetic Field
ConnectedUnconnected
ReconstructedIon Trajectories
Ion Reflection Source Map
26 Event Periods, June 29 – August 31
Lunar Precursor Effects