Theoretical understanding and development of realistic models for the various physical processes that occur are required to understand how particles in the outer regions of the magnetosphere become energized and make their way into the polar regions to produce the aurora. This project is a continuation of theoretical and model development research to further study the chaotic properties of various magnetotail models and the application of these models to tail energization processes. The project is described in four main areas of research pertinent to the role of stochastic particle orbits in magnetotail dynamics and the correct time scale for collisionless resistivity. These include studies of the irreversible behavior of current sheets and neutral line fields, the stochasticity of particle orbits, the response of ensembles of charged particles, diffusion coefficients and their dependence on model parameters, all directed towards understanding the evolution of particle distributions from the plasma sheet boundary layer to the central plasma sheet. ***//
