HR: 09:00h
AN: SM51D-05    [Abstracts]
TI: Kinetic simulations of magnetic reconnection in plasma with different beta values
AU: Brackbill, J
EM: jub@lanl.gov
AF: Dartmouth College, Dartmouth College, Hanover, 03755 United States
AU: Ricci, P
EM: paolo.ricci@dartmouth.edu
AF: Dartmouth College, Dartmouth College, Hanover, 03755 United States
AU: Lapenta, G
EM: lapenta@lanl.gov
AF: LANL, MS: K717, Los Alamos, 87544 United States
AU: * Daughton, W
EM: daughton@lanl.gov
AF: University of Iowa, University of Iowa, Iowa City, 52242 United States
AB: We present kinetic simulations of collisionless magnetic reconnection in Harris current sheets. We simulate plasmas with different beta values by varying the guide fields. For all values of $\beta >m_e/m_i$, fast reconnection is made possible by the separation of the electron and ion dynamics in the reconnection region. The primary mechanism that relaxes the frozen-in conditions is given by the non-gyrotropic electron pressure terms for all guide fields considered. The reconnection rate is then enhanced by the Whistler dynamics in high beta plasmas and by the Kinetic Alfv‚n Waves dynamics in lower beta plasmas. The guide field diminishes the reconnection rate and decreases the reconnection saturation level. The ion and electron flow pattern, acceleration, and heating are strongly influenced by the guide field. The simulations are performed by using two Particle-in-Cell codes: CELESTE3D, an implicit PIC code that runs on a single processor machine, and NPIC, a massive parallel explicit code that is able to resolve all the plasma time and length scales. The results of the two codes are compared in detail.
DE: 7827 Kinetic and MHD theory
DE: 7835 Magnetic reconnection
DE: 7843 Numerical simulation studies
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting