HR: 0830h
AN: SH31A-1078    [PDF]
TI: Component versus Anti-parallel Merging at the Magnetopause: Nonlinear Theory and Particle Simulations
AU: Quest, K
EM: quest@ece.ucsd.edu
AF: UCSD, Dept. of ECE, MC 0407, La Jolla, CA 92093-0407 United States
AU: * Karimabadi, H
EM: homa@ece.ucsd.edu
AF: UCSD, Dept. of ECE, MC 0407, La Jolla, CA 92093-0407 United States
AU: Daughton, W
EM: daughton@lanl.gov
AF: Los Alamos National Laboratory, MS B259, Los Alamos, NM 87544 United States
AB: One of the controversial issues regarding magnetic reconnection at the dayside magnetopause is the location where reconnection first occurs during periods of a large interplanetary magnetic field By. The question is whether magnetic reconnection can occur in locations where the field is not exactly anti-parallel. Nonlinear theory of the collisionless tearing mode predicts that in the presence of a guide field the instability saturates at too small amplitudes to be of any relevance at the magnetopause. Our recent linear theory analysis shows that the growth rate of the collisionless tearing mode remains significant even in the presence of a large guide field. This would indicate the possibility of both component and anti-parallel merging. However, aside from sizeable linear growth, the tearing mode must saturate at sufficiently large amplitude if it is to be a viable mechanism for reconnection at the magnetopause. To this end, we have performed a series of full particle simulations to address the nonlinear saturation of the tearing instability both in the presence and in the absence of the guide field. These simulations are the first of their kind and were performed for large mass ratios and with very high resolution in order to address the saturation problem. Our results show major deviations from previous studies of both anti-parallel and component merging scenarios. The results of these simulations and their implications for the magnetopause will be presented.
DE: 2740 Magnetospheric configuration and dynamics
DE: 2756 Planetary magnetospheres (5443, 5737, 6030)
DE: 7835 Magnetic reconnection
DE: 7843 Numerical simulation studies
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting