Sudden disruption of the cross-tail current in the magnetotail

A Hall magnetohydrodynamic simulation is used to study current dynamic processes with realistic magnetotail geometry. The simulation results indicate that sudden disruption of cross-tail current at the near Earth region inside 15R(E) is triggered by fast magnetic reconnection with the reconnection rate similar to 0.15. The cross-tail current density exhibits an impulsive intensification in the late growth phase. The magnitude of the current increases more than one order within a few minutes. After the reconnection onset, the cross-tail current is suddenly disrupted in a few Alfven times, which is in good agreement with that from the satellite observations. Associated with the current disruption, the tail-like geometry becomes a dipolarlike structure with an impulsive enhancement of the magnetic field B-z. Large increases of the electric field and Earthward bulk flow in this simulation are observed immediately after the reconnection onset. (C) 2008 American Institute of Physics.