HR: 0800h
AN: SH51B-1206    [Abstracts]
TI: Formation of the solitary bow shock and its dependence on IMF direction
AU: * Omidi, N
EM: omidi@solanasci.com
AF: Solana Scientific Inc., 777 S. Pacific Coast Hwy Suite 208-B, Solana Beach, ca 920752624 United States
AU: Sibeck, D
EM: david.sibeck@gsfc.nasa.gov
AF: NASA/GSFC, LEP Code 696 8800 Greenbelt Rd, Greenbelt, MD 20771 United States
AB: Using global hybrid (kinetic ions, fluid electrons) simulations of the bow shock, we have recently demonstrated that a portion of the bow shock is replaced with a solitary (localized) shock. The plasma and field jumps within the solitary shock are similar to those at fast magnetosonic shocks. Downstream of the solitary shock (in magnetosheath), the average density and magnetic field strength is comparable to those in the solar wind with highly non-thermal ion distribution functions. As a result, fast magnetosonic waves are generated in this region which are associated with large amplitude fluctuations in the density and magnetic field. Many signatures associated with the solitary bow shock are similar to a subset of past observations of hot flow anomalies (HFA). We attribute the formation of the solitary shock to a conflict between macroscopic requirements of magnetosheath flow around the magnetopause and microscopic requirements associated with ion deceleration and heating at the shock. Specifically, if the macroscopically required flow and magnetic field directions lead to a convection electric field, with component along the shock normal, pointing into downstream the shock is replaced with a solitary shock. This is because at the normal shocks, this component of the electric field points into the upstream contributing to ion deceleration, reflection and ultimate heating. In this study, we examine the formation of solitary shock as a function of direction of the interplanetary magnetic field (IMF).
DE: 2154 Planetary bow shocks
DE: 2753 Numerical modeling
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005