GLOBAL MODELING OF THE PLASMASPHERE FOLLOWING STORM SUDDEN COMMENCEMENTS

We examine the dynamics of the outer plasmasphere during 10 post-ssc e vents by comparing observations of cold, dense ions from Los Alamos ma gnetospheric plasma analyzers on board three widely spaced geosynchron ous satellites with output from the Magnetospheric Specification and F orecast Model (MSFM). The MSFM is a data-driven, operational space wea ther specification and forecast code originally designed to facilitate U.S. Air Force spacecraft operations. For this study we modified the MSFM to include a cold plasmaspheric ion population that was subject t o the effects of ionospheric refilling. We utilized the electron densi ty model of Carpenter and Anderson [1992] and the assumption of charge neutrality to initialize the plasmaspheric proton density within a sp ecified plasmapause. This configuration was then allowed to evolve und er the effects of E x B drift and refilling. The modified MSFM clearly shows the development and westward transport of duskside plasmaspheri c plumes/tails during periods of enhanced convection and the eastward transport of these structures during decreasing activity. We present a detailed comparison between the data and the model output for one cas e and a ''statistical'' analysis of the comparison for all 10 cases. W e also compare the model results with previously published observation s of plasmapsheric ions and models of plasmaspheric dynamics. The MSFM was able to systematically reproduce the geosynchronous observations with good accuracy in both local time placement and density level. We find the modified MSFM to be an improvement upon previous plasmaspheri c models and a useful tool in the interpretation of spatially and temp orally separated geosynchronous observations.