Project Summary Nagy/ATM-9412363 This continuation of an ongoing grant will support ionosphere- plasmasphere studies. The project will explore the role of the ring current as a major source of energy for the subauroral to low latitude ionosphere. One focus of the program will be on the decay of the ring current as a result of pitch-angle scattering and energy diffusion and the associated aeronomical consequences. In addition, the investigators will continue to explore the Coulomb interaction between the ring current and plasmaspheric particles . Another important element of the proposed program will be an investigation of the ionospheric response to energetic inputs from the ring current and electrodynamic coupling processes in the subauroral region.