HR: 17:15h
AN: SM52F-06    [PDF]
TI: MHD Simulations of SIs observed by Polar
AU: * Fowler, G J
EM: gfowler@igpp.ucla.edu
AF: UCLA - IGPP, 3845 Slichter Hall, Los Angeles, CA 90095 United States
AU: Russell, C T
EM: ctrussell@igpp.ucla.edu
AF: UCLA - IGPP, 3845 Slichter Hall, Los Angeles, CA 90095 United States
AU: Raeder, J
EM: J.Raeder@unh.edu
AF: UNH - Dept. of Physics & Space Science Center, 245G Morse Hall 39 College Rd., Durham, NH 03824 United States
AB: We use the UCLA MHD Geospace General Circulation Model (GGCM) to simulate Sudden Impulses (SI) observed by the Magnetic Field Experiment (MFE) onboard Polar. SI's are observable on the surface of the Earth as abrupt changes in the magnetic field magnitude caused by thin solar wind discontinuities across which the solar wind dynamic pressure abruptly and significantly increases. They compress the magnetosphere as they move past the Earth. The empirical T89 and T96 models developed by N. Tsyganenko can be used to predict the steady state changes in field magnitude but an MHD model can also resolve the temporal evolution of the SI signal. Since the rise time of an SI is used to determine the distance a shock travels along the length of the magnetosphere the MHD model is more useful for predicting such an occurrence. By varying the speed of a shock, and other solar wind parameters, we investigate the respective effect that various parameters have on the rise time and magnitude of an SI.
DE: 2730 Magnetosphere--inner
DE: 2731 Magnetosphere--outer
DE: 2753 Numerical modeling
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting