HR: 15:25h
AN: SA13B-08    [Abstracts]
TI: Analyzing Electric Field Morphology Through Data-Model Comparisons of the GEM IM/S Assessment Challenge Events
AU: * Liemohn, M W
EM: liemohn@umich.edu
AF: University of Michigan, 2455 Hayward St., Ann Arbor, MI 48109-2143 United States
AU: Ridley, A J
SA13B-08 AF: University of Michigan, 2455 Hayward St., Ann Arbor, MI 48109-2143 United States
AU: Kozyra, J U
SA13B-08 AF: University of Michigan, 2455 Hayward St., Ann Arbor, MI 48109-2143 United States
AU: Gallagher, D L
SA13B-08 AF: National Space Science and Technology Center, 320 Sparkman Drive NASA/MSFC, XD12, Huntsville, AL 35805 United States
AU: Thomsen, M F
SA13B-08 AF: Los Alamos National Laboratory, NIS-1, MS D466, Los Alamos, NM 87545 United States
AU: Brandt, P C
SA13B-08 AF: Johns Hopkins University, Applied Physics Laboratory 11100 Johns Hopkins Road, Laurel, MD 20723 United States
AU: Goldstein, J
SA13B-08 AF: Southwest Research Institute, 6220 Culebra Rd., San Antonio, TX 78238
AU: Henderson, M G
SA13B-08 AF: Los Alamos National Laboratory, NIS-1, MS D466, Los Alamos, NM 87545 United States
AU: Denton, M H
SA13B-08 AF: Los Alamos National Laboratory, NIS-1, MS D466, Los Alamos, NM 87545 United States
AB: The storm-time inner magnetospheric electric field morphology and dynamics is assessed by comparing numerical modeling results of the plasmasphere and ring current with many in situ and remote sensing data sets. Two magnetic storms are analyzed, April 22, 2001 and October 21-23, 2001, which are the events selected for the Geospace Environment Modeling (GEM) Inner Magnetosphere/Storms (IM/S) Assessment Challenge (IMSAC). The IMSAC seeks to quantify the accuracy of inner magnetospheric models as well as synthesize our understanding of this region. For each storm, the ring current-atmosphere interaction model (RAM) and the dynamic global core plasma model (DGCPM) were run together with various settings for the large-scale convection electric field and the nightside ionospheric conductance. Modeled plasmaspheric parameters were compared with IMAGE-EUV plasmapause extractions and LANL-MPA plume locations and velocities. Modeled ring current parameters were compared with Dst*, LANL-MPA fluxes and moments, IMAGE-MENA images, and IMAGE-HENA images. Both qualitative and quantitative comparisons were made to determine the electric field morphology that allows the model results to best fit the plasma data at various times during these events. It was determined that a shielded Volland-Stern field description driven by the 3-hour Kp index yields moderately accurate results. The simulations with self-consistent electric fields were, in general, better than those with prescribed field choices. This indicates that the time-dependent modulation of the inner magnetospheric electric fields by the nightside ionosphere is quite significant for accurate determination of these fields (and their effects). However, the rankings between the simulations varied depending on the storm and the data set(s) used in determining the order, indicating that each field description did well for some place, time, and energy range during the events, as well as doing less well in other places, times, and energies. Time-dependent settings in the electric field calculation, rather than the fixed values used in the current simulations, are expected to greatly improve the ability of models to track the observations over the course of the storms.
DE: 2730 Magnetosphere: inner
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 2768 Plasmasphere
DE: 2778 Ring current
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005