9224549 Seyler Three separate, but related topics will be investigated concerned with small and intermediate scale phenomena of the magnetosphere- ionosphere system and the role that they play in mediating the coupling, energetics and dynamics of the auroral zone. The first topic is an exploration of the small and intermediate scale structure of auroral arcs using a three-dimensional simulation model that has been refined over the past four years. The second subject is concerned with the auroral acceleration of electrons through wave processes, including Alfven wave acceleration and acceleration through the parametric decay of auroral kilometric radiation (AKR). Recent sounding rocket observations (TOPAZ I, II and III) have found tranverse ion acceleration events associated with intense lower-hybrid wave packets. The third topic of inquiry will explore the characteristics of lower-hybrid wave phenomena in the upper auroral ionosphere. We presently have at our disposal three-dimensional nonlinear simulation models for lower-hybrid waves which we will use to compare to sounding rocket observations as well as to test the theories of lower-hybrid collapse and the associated transverse ion acceleration. ***
