HR: 0800h
AN: SM41C-1197    [Abstracts]
TI: Measurements and Modeling of Ionosphere-Plasmasphere Transport
AU: * Sandel, B R
EM: sandel@arizona.edu
AF: Lunar and Planetary Laboratory, University of Arizona, Sonett Space Sciences Building, 1541 E. University Blvd., Tucson, AZ 85721 United States
AU: Denton, M H
EM: mhdenton@lanl.gov
AF: Space Science and Applications (ISR-1), Los Alamos National Laboratory, PO Box 1663, MS D466, Los Alamos, NM 87545 United States
AB: A fundamental aspect of the coupling between Earth's ionosphere and inner magnetosphere is the flow of ionospheric plasma that supplies material to the plasmasphere. Using global observations of the He⁺ column abundance made by the IMAGE Extreme Ultraviolet Imager, we investigate refilling of the plasmasphere after erosion events associated with geomagnetic storms. To minimize the confounding effects of phenomena other than refilling, we first focus on an usually quiet period of several days beginning on 27~June 2001. Just prior to this time, a moderate erosion event moved the plasmapause inward to L=3--4. During the next 3 days, the plasmasphere refilled so that the plasmaspause moved outward past geosynchronous orbit. For this and other similar study periods, we compare the He⁺ column abundances inferred from the EUV images with the predictions of the SUPIM model. The model solves the equations of continuity, momentum and energy balance that describe the physical and chemical processes occurring along closed field lines, and output from the model includes the He⁺ abundance. Comparing the model results to the azimuthally-averaged measurements shows generally good agreement, both in the rates of refilling as a function of radial distance and in the final shape of the radial profile of He⁺ column abundance. A more-detailed view, including analysis of azimuthal structure in the EUV images, suggests that the refilling rate is not always uniform in azimuth.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2730 Magnetosphere: inner
DE: 2768 Plasmasphere
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005