HR: 1340h
AN: SM43A-1151    [Abstracts]
TI: Initial Results from An MHD Simulation of Ganymede­_s Magnetosphere
AU: * JIA, X
EM: xzjia@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, University of California,Los Angeles, Los Angeles, CA 90095-1567 United States
AU: Walker, R J
EM: rwalker@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, University of California,Los Angeles, Los Angeles, CA 90095-1567 United States
AU: Kivelson, M G
EM: mkivelson@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, University of California,Los Angeles, Los Angeles, CA 90095-1567 United States
AU: Linker, J A
EM: linkerj@saic.com
AF: Science Applications International Corporation, SAIC, San Diego, CA 92121-1578 United States
AB: Three-dimensional resistive MHD simulations were conducted to study the interaction between Jupiter­_s corotating plasma and Ganymede­_s internal magnetic field. We ran the simulations using different initial states that represent the different plasma and magnetic field environments corresponding to the six Galileo encounters. Since Ganymede­_s internal field is nearly anti-parallel to Jupiter­_s magnetospheric field, a small reconnecting magnetosphere was produced in the simulation as expected. We­_ve found a small closed field line region near the equator and a large polar cap region containing filed lines that link to Jupiter. The magnetic fields from the simulation were evaluated along each flyby trajectory and compared with Galileo observations. The results gave good agreement between the observations and the simulation. The locations of the separatrices between Jovian field lines and those field lines connected to Ganymede at one or both ends are consistent with the results inferred from a vacuum superposition model (Kivelson et al. [1998]) and the energetic particle observations. We also show that the dynamic pressure of the upstream flow and the nature of Ganymede­_s ionosphere can be important factors affecting the topology of the magnetosphere. High dynamic pressure can expand the polar cap region and cause the equatorial standoff point to move close to Ganymede. Different ionization rates and neutral distributions in Ganymede­_s ionosphere will be used in future work to investigate the effect of the ionospheric boundary on the magnetosphere.
DE: 6062 Satellites
DE: 6218 Jovian satellites
DE: 2732 Magnetosphere interactions with satellites and rings
DE: 2753 Numerical modeling
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting