Plasmaspheric Erosion Jerry Goldstein(1), Bill Sandel (2), Stan Sazykin (1), Richard Wolf (1), Robert Spiro (1), Patricia Reiff(1). 1 - Rice University, Dept Physics and Astron, Houston, TX 2 - University of Arizona, Lunar and Planetary Lab, Tucson, AZ The plasmapause is the outer boundary of the Earth's plasmasphere. Decades of in situ and ground-based whistler observations have shown that a picture involving an interplay between co-rotation and convection can serve as a starting point for understanding the physics of plasmaspheric erosion. However, the details of this erosion process remain unknown. The IMAGE satellite's extreme ultraviolet (EUV) imager, which routinely obtains full global images of the plasmasphere as seen in 30.4 nm light, directly observed plasmaspheric erosion on 2000 July 10 and 2001 June 2. We investigate the problem of plasmspheric erosion, presenting IMAGE observations of erosion events, and simulation results fo the Rice Convection Model (RCM) and Magnetospheric Specification Model (MSM). As a byproduct of the erosion process, the dayside is apparently filled with a "cape" of eroded plasma that gradually (over the course of hours) evolves into a duskside plasmaspheric tail. We also study this tail formation process as seen by EUV, RCM and MSM. _______________ Fall 2002 Meeting of the American Geophysical Union San Francisco, CA, USA, 6-10 December 2002