SIMULATION OF THE MARCH 9, 1995, SUBSTORM - AURORAL BRIGHTENING AND THE ONSET OF LOBE RECONNECTION

A global MHD simulation of an isolated substorm that occurred on March 9, 1995 is presented. The simulation, driven with solar wind data pro vided by the Wind satellite, reproduced to a surprising degree the evo lution of substorm activity. The onset of the expansion phase was coin cident with the penetration of an electric field spike into the near-E arth region. This impulse launched a tailward propagating signal (rare faction wave) that enhanced reconnection in the mid tail. Substorm int ensification was correlated with the enhancement of the reconnection r ate at the preexisting reconnection region located at 30 R-E. The impo rtance of the electric field spike in correlating ionospheric and magn etospheric aspects of the substorm is emphasized.