HR: 1340h
AN: SM43C-1234    [Abstracts]
TI: On the Magnetopause Crossing at Ganymede
AU: * JIA, X
EM: xzjia@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, University of California,Los Angeles, 405 Hilgard Ave., Los Angeles, CA 90095-1567
AU: Walker, R J
EM: rwalker@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, University of California,Los Angeles, 405 Hilgard Ave., Los Angeles, CA 90095-1567
AU: Kivelson, M G
EM: mkivelson@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, University of California,Los Angeles, 405 Hilgard Ave., Los Angeles, CA 90095-1567
AU: Linker, J A
EM: linkerj@saic.com
AF: Science Applications International Corporation, 10260 Campus Point Drive, San Diego, CA 92121-1578
AB: We have used Galileo magnetometer, Plasma Wave Subsystem (PWS) and Energetic Particle Detector (EPD) observations to investigate Ganymede's magnetopause. The magnetopause crossing times indicated by the magnetic field rotation are consistent with those indicated by the enhancement of wave activity in the PWS data. The EPD data from these passes shows consistent decreases in the rate counts of particles and change in the particles anisotropy when the spacecraft crossed the boundary. For the G8, G28 and G29 encounters, electric field broadband noise bursts have been found in the PWS data for inbound (outbound) crossings before (after) the magnetic field rotation. These bursts are similar to the electrostatic noise bursts that were reported by Gurnett et al. (1996) for the G1 flyby. Strong wave like magnetic perturbations were observed near Ganymede's magnetopause on all six Galileo flybys. These perturbations have strong power at a period of 10 seconds which is very close to the O+ gyro period in the local magnetic field (~100nT). The perturbations were mostly transverse to the magnetic field. On the G8 and G28 flybys Galileo passed into the closed field line region of Ganymede's magnetosphere. On those passes waves with large amplitudes were observed on both sides of the magnetopause. The Kelvin-Helmholtz instability is one possible mechanism responsible for generating these waves. Further analysis of the wave properties as well as the local plasma environment will be investigated to understand these boundary waves. An MHD simulation will be used to investigate the field geometry and overall plasma environment of Ganymede.
DE: 2724 Magnetopause and boundary layers
DE: 2732 Magnetosphere interactions with satellites and rings
DE: 2756 Planetary magnetospheres (5443, 5737, 6033)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005