Magnetic Reconnection Rate in Collisionless Plasma.

The physical processes controlling the magnetic reconnection rate are of principle importance for many phenomena in space plasma. Comparative study of magnetic reconnection in kinetic and fluid simulations demonstrated that the reconnection rate is controlled by ion nongyrotropic behavior near the reconnection site. We will demonstrate that reconnection electric field can be estimated as a convection electric field v x B at the edge of the non-MHD diffusion region and can be incorporated into the MHD description. We employ small scale and global MHD simulation codes and introduce non-ideal corrections to the induction equation in terms of nongyrotropic corrections to the electric field. The role of the nongyrotropic effects near the reconnection site on the global dynamics will be analyzed.