LUNAR PRECURSOR EFFECTS IN LUNAR PRECURSOR EFFECTS IN THE TERRESTRIAL MAGNETOSPHERE AND SOLAR WIND Jasper S. Halekas Space Sciences Laboratory Uni ersit of California Berkele University of California, Berkeley ARTEMIS Science Working Team Meeting 9/14 ‐ 16/2011
The Lunar Space Plasma Environment: Pre ‐ ARTEMIS Environment: Pre ARTEMIS
Precursor Effects in the Terrestrial Magnetosphere All Electrons Upgoing e ‐ (0 ‐ 15°) Downgoing e ‐ (165 ‐ 180°) fp fce EFI FFT EFI FFT EFI Background EFI Background fp SCM FFT fce B Wavelets B Wavelets Spin Tone fci B Field
Free Energy Sources: Reflected Electrons in Magnetosphere Converging Magnetic Field Lines above Crustal Magnetic Fields Loss Cone Beam Plasma Electrons Follow Magnetic Field Lines Field Lines and Reflect from E & B Beam + Loss Cone: Beam + Loss Cone: Secondary Electrons Produced By Combined Accelerated Upward Magnetic & Electrostatic g D Downward d Electric Field E = ‐ U Δ Effects Near Surface
Polarization Properties B0 Waves propagating anti ‐ parallel to field Narrowband EXB Coherent E B Right ‐ Handed Right Handed Parallel ‐ Propagating • Wave properties all consistent with parallel propagating whistlers coming down • Wave properties all consistent with parallel ‐ propagating whistlers coming down the magnetic field line towards the Moon
Instability Conditions Streaming instabilities where df/dv || positive g || p EFI SCW Whistlers correlate with edges of loss cone: i.e. df/dv perp positive Reduced Distribution Function Whistler Mode: ω /k, ( ω ce ‐ω )/k
Ions in the Mix? • Waves near f i modulate both the electron beam and the whistlers Waves near f ci modulate both the electron beam and the whistlers • Possible sources: Electron beam, shadowed ion distributions, bi ‐ ion streaming ICW ? ICWs? Electron Beam Modulated Electron Beam Modulated Loss Cone Modulated Whistlers Modulated FGM Wavelets Proton & Helium Cyclotron Frequencies
Precursor Effects in the Solar Wind Solar Wind Ions Upgoing e ‐ (0 ‐ 15°) Upgoing e (0 15 ) Downgoing e ‐ (165 ‐ 180°) EFI FFT SCM FFT B Wavelets B Field SZA of Surface Connection
Free Energy Sources: Reflected Electrons in Solar Wind Electron Fitzenreiter et al., 1990 Trajectory Magnetic Field Convection Electric Field Generalized obstacle with magnetic field gradient and/or electrostatic potential gradient Adiabatic Reflection in dHT Frame Gives you “Ears” in Solar Wind Frame
Whistler Cyclotron Resonance Conditions Resonance Conditions EFI SCW Reduced Distribution Function ( ω ce ‐ω )/k : ω , k on whistler branch ( )/ , ce
Ion Observations P2 Ions Foreshock Ions P1 Ions Reflected Protons P1 Reduced Dist. Funct. P1 Power Spectrum p Parallel ‐ Propagating P1 Propagation P1 Propagation RH, LH P1 Ellipticity P1 Ellipticity
Free Energy Sources: Reflection From Crustal Magnetic Fields Reflected Protons Follow Pickup Reflected Proton Fluxes Ion Trajectories j L Lue et al., 2010 t l Distribution Near Cycloid “Cusp” IMF SW
Pickup Ion Trajectories Reconstructed Ion Trajectories j Connected Unconnected Surface Crustal Magnetic Field Surface Crustal Magnetic Field
Ion Reflection Source Map 26 Event Periods, June 29 – August 31
Lunar Precursor Effects
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