The ultimate objective of the proposed research is to develop an improved model of the ionospheric electric potentials in the polar cap. The initial step will be to determine the locations of the convection boundaries, and how the electric potential is distributed around the perimeter of the convection/electric field reversal boundaries under different orientations of the IMF and two categories of geomagnetic activity. Solving this problem is perceived to be the most critical step towards the development of a better model of ionospheric plasma convection. Measurements from the Vector Electric Field Instrument on DE-2 will be used to obtain a data base of boundary locations and electric potentials around the boundaries. The data will be sorted according to IMF orientation and substorm activity, then an innovative but proven method of fitting the data will be used to determine the locations of the convection boundaries and potential distribution as a function of magnetic local time. These measurements will next be used as the initial boundary conditions for numerical calculations, to produce reasonable models of ionospheric electric potentials. The results of this project will be needed to check the results of the GEM Program's global geospace general circulation model (GGCM), and could be useful in the development of the GGCM code. The proposed research will also help to obtain the objectives of the GEM program's substorm campaign.
