HR: 10:20h
AN: SA42A-01    [Abstracts]
TI: Testing the Hill-Siscoe Model of Polar Cap Potential Saturation Using Observations From the October/November 2003 Superstorms
AU: * Hairston, M R
EM: hairston@utdallas.edu
AF: Center for Space Sciences-University of Texas at Dallas, PO Box 830688 FO22, Richardson, TX 75083-0688 United States
AU: Lu, G
EM: ganglu@hao.ucar.edu
AF: UCAR - High Altitude Observatory, 3450 Mitchell Ln, Boulder, CO 80301 United States
AB: Under extreme conditions of the solar wind the induced cross polar cap potential in the ionosphere saturates, and this has been definitely demonstrated in recent studies. The Hill-Siscoe model (Siscoe et al., JGR-Space Physics, 2002) is the leading candidate to explain and predict the magnitude of the saturated potential as a function of the solar wind parameters and ionospheric conductivity. All the parameters in the Hill-Siscoe formula can be directly measured except for the average Pedersen conductivity, so this leaves a free parameter that may be adjusted to fit any set of observed data. In the absence of direct measurements of the Pedersen conductivity, we can use the conductivity from the AMIE procedure to test the Hill-Siscoe model. In this talk we compare the conductivity values from the AMIE runs for the October and November 2003 superstorms with the predicted conductivity values from the Hill-Siscoe model based on the observed data from the DMSP, ACE, and GEOTAIL spacecraft.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2475 Polar cap ionosphere
DE: 2708 Current systems (2409)
DE: 2784 Solar wind/magnetosphere interactions
DE: 2788 Storms and substorms
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting