HR: 16:30h
AN: SM54A-03    [Abstracts]
TI: Ionospheric Prompt Penetration Electric Fields: Comparison of First-principle Solutions With Observations
AU: * Sazykin, S
EM: sazykin@rice.edu
AF: Rice University, Physics and Astronomy Dept., MS-108, 6100 South Main St., Houston, TX 77005-1892 United States
AU: Wolf, R A
EM: rawolf@rice.edu
AF: Rice University, Physics and Astronomy Dept., MS-108, 6100 South Main St., Houston, TX 77005-1892 United States
AU: Fejer, B G
EM: bfejer@cc.usu.edu
AF: Utah State University, Center for Atmospheric and Space Science, 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: Spiro, R
EM: spiro@rice.edu
AF: Rice University, Physics and Astronomy Dept., MS-108, 6100 South Main St., Houston, TX 77005-1892 United States
AU: De Zeeuw, D L
EM: darrens@umich.edu
AF: University of Michigan, Space Physics Research Laboratory, 2455 Hayward, Ann Arbor, MI 48109-2143 United States
AU: Gombosi, T I
EM: tamas@umich.edu
AF: University of Michigan, Space Physics Research Laboratory, 2455 Hayward, Ann Arbor, MI 48109-2143 United States
AU: Caldwell, J
AF: Rice University, Physics and Astronomy Dept., MS-108, 6100 South Main St., Houston, TX 77005-1892 United States
AB: Prompt penetration of magnetospheric convection electric fields to the mid- and low-latitude ionosphere is caused by transient changes in the shielding capacity of region-2 Birkeland currents, reconfiguration of inner magnetospheric magnetic field, and other dynamic processes ultimately originating in the solar wind. During magnetically disturbed times, these electric fields cause substantial redistribution of ionospheric electron densities, and, in the equatorial region, are a major parameter controlling linear growth rates and non-linear evolution of spread-F plasma instabilities. In this paper, we use the global numerical model BATSRUS-RCM, a global MHD code with an inner magnetospheric module, to study time propagation of prompt penetration electric fields in response to idealized changes in the solar wind conditions. For the first time, we are able to compute, from first principles, solutions that link changes in the solar wind parameters (e.g., IMF strength and orientation) to the local-time dependent electric fields at the equator of the Earth. These theoretical solutions will be compared with a number of case studies, relating cases of prompt-penetration electric fields observed with the Jicamarca Observatory incoherent scatter radar to changes in the solar wind conditions.
DE: 2411 Electric fields (2712)
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2712 Electric fields (2411)
DE: 2753 Numerical modeling
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting