HR: 0800h
AN: SH31A-1169    [Abstracts]
TI: Perpendicular shock structure: a small amplitude model
AU: * Bedros, R
EM: rbedr001@student.ucr.edu
AF: IGPP, University of California, Riverside, CA 92521 United States
AU: Zank, G P
EM: zank@ucr.edu
AF: IGPP, University of California, Riverside, CA 92521 United States
AU: Dasgupta, B
EM: dasgupta@citrus.ucr.edu
AF: IGPP, University of California, Riverside, CA 92521 United States
AU: Webb, G M
EM: gmwebb@ucr.edu
AF: IGPP, University of California, Riverside, CA 92521 United States
AB: Reflection of ions by the cross-shock electrostatic potential is the primary dissipation mechanism at a quasi-perpendicular shock in the solar wind. Recently, the role of pickup ions and their greater facility for reflection by the cross-shock potential has raised important questions for injection and acceleration of pickup ions at, for example, the heliospheric termination shock. However, before these questions can be fully addressed, a better understanding of ion reflection and shock structure at a quasi-perpendicular shock is needed. We revisit the question of ion reflection and shock structure based on a fluid model and appropriate source terms that take into account the energization of the reflected ions by the motional electric field immediately upstream of the shock. By assuming that the source terms remain small, we develop a perturbation expansion solution of the model equations and derive a modified form of the classical Burgers equation. However, the dissipation term in our Burgers' equation is determined by the efficiency of the ion reflection process at the shock front, demonstrating explicitly that ion reflection should be viewed as a dissipative process and one that determines the scale length of the quasi-perpendicular shock.
DE: 2139 Interplanetary shocks
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting