HR: 1340h
AN: SH43A-1137    [Abstracts]
TI: Hybrid Simulations of the solar wind interaction with Comet 19P/Borrelly
AU: * Delamere, P
EM: delamere@lasp.colorado.edu
AF: University of Colorado, Laboratory for Atmospheric and Space Physics CB 392 Duane Physics D133 University of Colorado, Boulder, CO 80309 United States
AU: Bagenal, F
EM: bagenal@colorado.edu
AF: University of Colorado, Laboratory for Atmospheric and Space Physics CB 392 Duane Physics D133 University of Colorado, Boulder, CO 80309 United States
AB: Observations of Comet 19P/Borrelly during the Deep Space 1 (DS1) flyby on September 22, 2001 with the Plasma Experiment for Planetary Exploration (PEPE) have shown asymmetries in the plasma environment boundaries (i.e. 10% solar wind slowing, cometary ion pickup, bow shock, sheath of heated plasma, cometopause and the center of ion density). All of the observed features were offset to the north of the nucleus-Sun line. Preliminary explanations for these asymmetries suggest that the coma itself is responsible due to, perhaps, well-collimated dayside jets directed northward of the nucleus. An alternative explanation involves the kinetics of the heavy pickup ions by the solar wind. In an attempt to understand the asymmetric Borrelly plasma environment we have used a hybrid plasma simulation to isolate the role of ion pickup. Our hybrid code uses a fluid treatment for the solar wind protons and massless electrons and a kinetic treatment for the pickup ions. Using an isotropic neutral cloud distribution, we are able to isolate the effects of pickup ion motion. Our results suggest that the pickup ions can contribute to the asymmetry in the plasma environment; however, the northward shift of all plasma boundaries requires both large ion gyroradius effects together with a northward-shifted neutral gas cloud.
DE: 6005 Atmospheres (1060)
DE: 6023 Comets: dust tails and trails (6210)
DE: 6025 Interactions with solar wind plasma and fields
DE: 6026 Ionospheres (2459)
DE: 6050 Plasma and MHD instabilities (2149, 2752, 7836)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005