HR: 17:40h
AN: SH22C-07    [PDF]
TI: Quasi-Perpendicular Shocks: Full Particle Simulations With Realistic Ion to Electron Mass Ratio
AU: Sidorenko, I
EM: irina.sidorenko@ipp.mpg.de
AF: Max-Planck-Institut f. extraterr. Physik, P.O. Box 1312, Garching, 85741 Germany
AU: * Scholer, M
EM: mbs@mpe.mpg.de
AF: Max-Planck-Institut f. extraterr. Physik, P.O. Box 1312, Garching, 85741 Germany
AU: Matsukiyo, S
EM: matsu@ipp.mpg.de
AF: Max-Planck-Institut f. extraterr. Physik, P.O. Box 1312, Garching, 85741 Germany
AB: In quasi-perpendicular shocks with a Mach number below the whistler critical Mach number $M_w$ the whistler precursor wave train is an essential part of the shock. $M_w$ depends on the magnetic field - shock normal angle $\Theta _{Bn}$ and on the ion to electron mass ratio. It has been proposed that above $M_w$ nonlinear wave steepening of the upstream whistler cannot be balanced anymore by dispersion and dissipation, and that this leads to shock nonstationarity. Full particle (PIC) simulations of shocks above the whistler critical Mach number with a reduced ion to electron mass ratio have indeed resulted in shock nonstationarity. We present PIC simulations of collisionless shocks over a wide range of $\Theta _{Bn}$ and Mach number with the realstic ion to electron mass ratio. It will be shown that the modified two-stream instability (MTSI) between incident solar wind electrons and incident and reflected solar wind ions occurs in the foot of the shock and leads to a considerable modification of the shock structure. This has consequences for the nonstationarity, for the various lenghth scales, and for the reflection rate of the specularly reflected ions. Simulations with an ion to electron mass ratio of about 400 or less cannot show these processes, since the growth rate of the MTSI depends strongly on mass ratio.
DE: 2154 Planetary bow shocks
DE: 7843 Numerical simulation studies
DE: 7851 Shock waves
DE: 7867 Wave/particle interactions
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting