This grant will support a study of the intermediate scale coupling of the solar wind, magnetosphere and ionosphere by a combination of analytic and numerical techniques. Coupling on these scales is important and interesting, primarily due to the importance of non-ideal MHD processes on the dynamics. The grant will address three areas: nonlinear effects, compressional effects and kinetic effects. Nonlinearities become quite important in the dynamics of small scale currents such as those associated with flux transfer events. A model to describe the coupling between compressional and transverse MHD waves in a generalized geometry will be developed, and used to study the effect coupling may have on the generation of field-aligned currents and micropulsations. The effects of single particle and collective plasma dynamics will be investigated by means of test particle and self-consistent plasma simulation, and these studies will be used to improve the inclusion of these effects on MHD models. The final goal will be an integration of these effects into an overall MHD model of auroral flux tubes and an understanding of the aurora itself.
