GLOBAL SUBSTORM CYCLE - WHAT CAN THE MODELS TELL US

Magnetospheric substorms represent the basic dynamic process in the co upled solar wind-magnetosphere-ionosphere system. Recent satellite mis sions have considerably advanced our means to monitor this vast enviro nment. These observations are interpreted in the context of a hierarch y of models: Global MHD simulations and various techniques of nonlinea r physics are used to characterize the large-scale features, whereas m icrophysical models are used to study the small-scale processes. Empir ical models are described in order to address questions that involve m eso-scale or multi-scale phenomena. We discuss some of the recent obse rvations and relate those to new advancements in various modeling tech niques.