HR: 0830h
AN: SM21B-0195    [PDF]
TI: Ion and Electron Dissipation in Collisionless Slow-Mode Shocks
AU: * Yin, L
EM: lyin@lanl.gov
AF: Los Alamos National Laboratory, Mail Stop B259, Plasma Physics Group, Los Alamos, NM 87545 United States
AU: Winske, D
EM: winske@lanl.gov
AF: Los Alamos National Laboratory, Mail Stop B259, Plasma Physics Group, Los Alamos, NM 87545 United States
AU: Daughton, W
EM: daughton@lanl.gov
AF: Los Alamos National Laboratory, Mail Stop B259, Plasma Physics Group, Los Alamos, NM 87545 United States
AU: Coroniti, F
EM: coroniti@astro.ucla.edu
AF: Department of Physics and Astronomy, UCLA, 405 Hilgard Ave., Los Angeles, CA 90095-1547 United States
AB: Ion and electron dissipation in collisionless slow shocks are examined using one-dimensional hybrid (kinetic ions, massless fluid electrons) and full particle (kinetic ions and electrons) simulations. In the hybrid code, two types of electron fluid models are used to determine the electron physics: an adiabatic model, which uses a scalar electron pressure, and a pressure tensor model, in which electron quasi-viscous effects are retained. At moderate oblique angles, the shock dissipation in both the hybrid and the full particle simulations is provided primarily by the ions. For very oblique angles, however, results from hybrid simulations using an adiabatic electron fluid differ from the full particle results, which indicates that the ion dissipation alone is inadequate to set up the shock, and that additional electron dissipation is needed. It is seen in the full particle simulations that at very oblique angles the large mirror effects result in a significant difference in the parallel and perpendicular electron pressures with respect to the local magnetic field. While the electron inertia is negligible, the electron pressure anisotropy gives rise to finite off-diagonal electron pressure tensor terms. Hybrid simulations including the electron quasi-viscous dissipation are presented, and it is concluded that inclusion of electron viscosity is the key element for providing adequate dissipation in setting up very oblique slow shocks such as those observed in the distant magnetotail.
DE: 2744 Magnetotail
DE: 2753 Numerical modeling
DE: 7843 Numerical simulation studies
DE: 7851 Shock waves
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting