Three-dimensional MHD simulations of the Earth's magnetosphere on Feb 9-101995 for northward interplanetary magnetic field and comparison of the lobe field with Geotail observations

Three-dimensional Global magnetohydrodynamic simulations of the quiet-time magnetosphere are compared to data obtained from the Geotail satellite. For the specific event on Feb. 9-10, 1995 when the interplanetary magnetic fie ld was quiet northward and Geotail was in the vicinity of the equatorial pl ane and around x=-20 R-E, the lobe field was found to be steady for 2.5 hou rs. During the time interval between UT 00:30, Feb. 10 and UT 3:00, Feb. 10 , the lobe field B-x is nearly zero and B-z is around 5 nT which is compara ble to the B-z (about 5 nT) of the EAR This is consistent with predictions from our recent steady-state simulations [Guzdar et al., 2001]. Also perfor ming real event simulations using the global MHD code we find that the time scale for the temporal evolution and magnitude of the the various componen ts of the lobe field agree well with Geotail observations.