This project will continue the development of the Wind Driven Magnetospheric-Ionospheric (WINDMI) model of the Earth's magnetosphere-ionosphere system. The model is a non-linear circuit-based simplification of the complex electrodynamic system. This approach is radically different from the magnetohydrodynamic (MHD) modeling efforts that have commonly been used in the last decade for modeling the magnetosphere and its interaction with the solar wind. The project will concentrate on the analysis of magnetospheric substorms and in particular will examine the events chosen for study in the Geospace Environment Modeling (GEM) program.