HR: 0830h
AN: SH31A-1081    [PDF]
TI: Gyrokinetic-Electron and Fully-Kinetic Ion Particle Simulation -- A Novel Numerical Model
AU: Chen, L
EM: liuchen@uci.edu
AF: University of California, Irvine, Department of Physics and Astronomy, 4129 Physical Sciences 2, Irvine, CA 92697-4575 United States
AU: Wang, X
EM: xywang@physics.auburn.edu
AF: Auburn University, Physics Department, 206 Allison Laboratory, Auburn, AL 36849-5311 United States
AU: * Lin, Y
EM: ylin@physics.auburn.edu
AF: Auburn University, Physics Department, 206 Allison Laboratory, Auburn, AL 36849-5311 United States
AU: Lin, Z
EM: zhihongl@uci.edu
AF: University of California, Irvine, Department of Physics and Astronomy, 4129 Physical Sciences 2, Irvine, CA 92697-4575 United States
AB: A novel 3-D numerical scheme is developed to investigate nonlinear plasma processes in collisionless plasmas. In this model, electron particle dynamics is handled by the gyrokinetic (GK) equations, and the ions are treated as fully kinetic (FK) particles. The code is designed as a reduced model to the existing full-particle codes. Due to disparate temporal and spatial scales between electrons and ions, full-particle codes have to employ either unrealistically high electron-to-ion mass ratio, $m_e/ m_i$, or length of simulation domain limited to a few ion Larmor radii, or/and time much less than the global Alfven time scale in order to accommodate available computing resources. In our new model, the rapid electron cyclotron motion is removed, while keeping realistic mass ratio $m_e/m_i$, finite electron Larmor radii, wave-particle interactions, and off-diagonal components of electron pressure tensor. Such a model is particularly adequate to problems in which wave modes ranging from Alfven waves to lower-hybrid/whistler waves need to be handled on equal footing. As an example, the code can be applied to magnetic reconnection with a finite guide magnetic field. The simulation model allows quasi-neutrality assumption, which leads to the suppression of high frequency electron plasma oscillations. The computation power can thus be significantly improved, and both collisionless physics at the reconnection X-line and that in the global scale can be included self-consistently at the same time. As a first step, the numerical calculation is benchmarked by comparison with theoretical analysis based on the linearized GK-electron and FK-ion equations. In this study, we present the fundamental equations of the scheme and the linear mode analysis based on the dispersion relation. Comparison is made between the numerical and analytical solutions, and between the normal mode solutions based on this model with GK-electron and FK-ions and various other known theoretical analyses.
DE: 7827 Kinetic and MHD theory
DE: 7835 Magnetic reconnection
DE: 7839 Nonlinear phenomena
DE: 7843 Numerical simulation studies
DE: 7871 Waves and instabilities
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting