Geophysical research letters vol:29 issue:23 pages:-
 We extend kinetic simulations of the Geospace Environment Modeling (GEM) magnetic reconnection challenge [Birn et al., J. Geophys. Res., 106, 3715, 2001] to a physical mass ratio, using the implicit Particle-in-Cell (PIC) code CELESTE3D which allows the use of a coarser grid and a bigger time step. We compare results for three values of the mass ratio m(i)/m(e) = 25 (GEM challenge standard mass ratio), m(i)/m(e) = 180 and the physical mass ratio m(i)/m(e) = 1836. The results of the three simulations are compared and the scaling laws based on reconnection via nongyrotropic electron pressure are verified.