An empirical model of the earth's plasmasphere

We present here an empirical model of plasmaspheric low energy plasma consisting of H+. The model is developed from a data base derived from measurements taken by the Retarding Ion Mass Spectrometer on the Dynamics Explorer 1 satellite. An analytical expression that reproduces the density profiles for moderate geomagnetic activity is given and discussed. This expression reproduces the density fall off in the ionosphere as well as the sharp density decrease at the plasmaspause.