Thin current sheet evolution as seen in observations, empirical models andMHD simulations

The inner and midtail current sheet is examined during a substorm on Dec 10 , 1996 using multispacecraft observations, empirical models, and global MHD simulations. Both the simulation and empirical magnetic field model show g ood agreement with observations, which substantially increases the confiden ce in both methods. Both locate the thin current sheet inner edge at simila r to 7 R-E, and give a scale size of similar to 15 R-E in tailward and cros s-tail directions. The MHD simulation confirms the empirical model result t hat the thin current sheet remained stable after a local auroral breakup an d indicates that the activity followed from flow channels generated at simi lar to 40 R-E independent of the thin current sheet evolution closer to the Earth.