Preliminary Comparisons between the Global Plasmasphere Ionosphere Density (GPID) Model and Observations Obtained by the RPI and EUV Imager Webb, P. A. Using the Radio Plasma Imager (RPI) on the IMAGE satellite, the local electron density can be separately calculated from observed dynamic resonances and the plasma spectrograms. An along the orbit electron density profile can be obtained by calculating the electron density at different points along the orbit, which can then be compared to the predictions of plasmaspheric electron density models. The theoretical based Global Plasmasphere Ionosphere Density (GPID) model has recently been developed by the author to simulate the global scale evolution of the number densities of the ions and electrons in the plasmasphere. Combined with the latest version of the International Reference Ionosphere (IRI), GPID can model the dynamic emptying caused by geomagnetic storms and the following refilling of the plasmasphere. Recently, GPID has been extended to include He+. This extension allows GPID predictions to be compared with the global images obtained from the EUV Imager on IMAGE. Prior to this improvement, GPID could only be compared to electron density measurements obtained from the RPI on IMAGE. The reason for this upgrade is to be able to combine and contrast the data from RPI and EUV with the predictions of GPID, in order to obtain a better understanding of what happens to plasma from the outer plasmasphere during geomagnetic storms. In particular, RPI data will be used in an attempt to track this plasma, which has proved elusive to track with EUV. _______________ To be presented at the Magnetospheric Imaging Workshop, Yosemite National Park, California, U.S.A., Feb. 5-8, 2002.