TRANSITION TO WHISTLER MEDIATED MAGNETIC RECONNECTION

The transition in the magnetic reconnection rate from the resistive ma gnetohydrodynamic (MHD) regime where the Alfven wave controls reconnec tion to a regime in which the ions become unmagnetized and the whistle r wave mediates reconnection is explored with 2-D hybrid simulations. In the whistler regime the electrons carry the currents while the ions provide a neutralizing background. A simple physical picture is prese nted illustrating the role of the whistler in driving reconnection and the rate of whistler mediated reconnection is calculated analytically . The development of an out-of-plane component of the magnetic field i s an observable signature of whistler driven reconnection.