Kinetic Modeling of the Plasmasphere

M. Anthony Reynolds
Department of Physics, Howard University, Washington, DC

Currently, there is renewed interest in the plasma density and temperature structure of the near-Earth space environment, both from a scientific point of view and for practical reasons (communications, GPS, etc.). Past research using both the measurement of whistler wave propagation and in situ satellite data has resulted in a good understanding of the basic features of this region. However, these methods have the inherent difficulty that only a small region of space is studied at any one time. Current and future satellites (NRL/ARGOS and NASA/IMAGE) will have the capability of imaging the entire near-Earth region in a global fashion, and the interpretation of these observations will need a strong theoretical modeling effort for success.

In this talk I will describe a multi-species, kinetic model that my colleagues and I have developed, and its application to the interpretation of remote sensing images. The distinctive feature of this model is that it includes the effects of diurnal convection on trapped particles and leads to a morphology of the outer plasmasphere that is different from that obtained by fluid models. In addition, the local time dependence of the altitude, density, and temperature of the ionosphere has recently been incorporated into the model, and I will describe these refinements. Finally, I will present synthetic images of the helium ions in the plasmasphere, similar to those that will be obtained by the imaging satellites.