In this proposal, we will address the physics of local and global conversion of magnetic free energy to particle kinetic energy during substorms. An understanding of these processes will be important implications to the global response of the magnetosphere to solar wind variations. For example, this could lead to an understanding of the partitioning of substorm released free energy between energy lost down the tail and work done on the inner magnetosphere and ionosphere. Also, such a theory of the global release of stored magnetic energy during substorms could have important implications for energy release phenomena in other space physics and astrophysical contexts. The difference between the presently proposed study and similar studies of the past is that our study will be based upon the current sheet catastrophe model for local current disruption c.f. Lui et al., 1988 . This model arises from time independent and time dependent calculations of 1D current sheet configurations with a nonzero Ey and nonzero Bz Burkhart et al., 1992a; Pritchett and Coroniti, 1993; Burkhart et al., 1993 . It was found in these calculations that under the quasi-static evolution of the boundary conditions a force imbalance, which we have called the current sheet catastrophe, develops. Subsequent time development leads to the turbulent destruction of the current sheet over some time interval and the conversion of the associated magnetic field energy to particle energy. In the proposed research, we shall perform ID calculations for a variety of initial conditions and boundary conditions to determine the robustness and scaling of the signatures of the current sheet catastrophe. We shall study the radial expansion of current disruption in a 2D, time-dependent, hybrid code, using, for the first cut, x-independent initial equilibria. We shall extend the 1D equilibrium calculations to include x-dependence and we shall study the expansion of activity and the corresponding local and global conversion of magnetic field energy to plasma energy using the x-dependent initial equilibria in a time-dependent, hybrid simulation code.
