HR: 0800h
AN: SM11A-1172    [Abstracts]
TI: Electron Physics in Slow-Mode Shocks
AU: * Yin, L
EM: lyin@lanl.gov
AF: Los Alamos National Laboratory, MS B259, X-1 Plasma Physics, Los Alamos, NM 87545 United States
AU: Winske, D
EM: winske@lanl.gov
AF: Los Alamos National Laboratory, MS B259, X-1 Plasma Physics, Los Alamos, NM 87545 United States
AU: Daughton, W
EM: william-daughton@uiowa.edu
AF: University of Iowa, Department of Physics and Astronomy, Iowa City, IA 52242 United States
AU: Coroniti, F V
EM: coroniti@astro.ucla.edu
AF: UCLA, Department of Physics, Los Angeles, CA 90095 United States
AB: Electron dynamics and dissipation in collisionless slow-mode shocks are examined using one-dimensional hybrid (kinetic ions, massless fluid electrons) and full particle (kinetic ions and electrons) simulations. The dynamics of slow shocks at very oblique shock angles (84 degrees) are explored for the upstream ion and electron beta value of 0.1. For these very oblique angles, results from hybrid simulations using an adiabatic electron fluid differ from results using the full particle code, which indicates that the ion dissipation alone is inadequate to set up the shock, and that additional electron physics is needed. Full particle simulations show that the downstream electron temperature becomes anisotropic at very oblique angles, i.e.,T\_e,par $>$ T\_e,per, where the subscripts are directions (parallel, perpendicular) with respect to the local magnetic field. The anisotropy results from both the large mirror effects and the electron heating due to the parallel electric field of very obliquely propagating kinetic Alfven waves. These primarily electrostatic waves that provide the heating give rise to steepened, spiky density fluctuations in the shock ramp. As a consequence, finite off-diagonal electron pressure tensor terms (quasi-viscous effects) are generated in the simulation frame. Inclusion of quasi-viscous effects in hybrid simulations with a model for the parallel wave heating allows the very oblique slow shocks observed in the distant magnetotail to be efficiently modeled.
DE: 2744 Magnetotail
DE: 2748 Magnetotail boundary layers
DE: 2753 Numerical modeling
DE: 2772 Plasma waves and instabilities
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting