HR: 1330h
AN: SA23A-04    [Abstracts]
TI: Formation of the large equatorial plasma depletions during superstorms by the ionosphere-thermosphere coupling effect
AU: * Kil, H
EM: hyosub.kil@jhuapl.edu
AF: Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 United States
AU: Paxton, L
EM: larry.paxton@jhuapl.edu
AF: Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 United States
AU: Crowley, G
EM: gcrowley@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, Tx 78228 United States
AU: Su, S
EM: t2700146@ncu865.ncu.edu.tw
AF: National Central University, Chung-Li, Taiwan
AU: Zhang, Y
EM: yongliang.zhang@jhuapl.edu
AF: Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 United States
AB: We investigate the formation mechanism of the severe equatorial plasma depletions during the the large geomagnetic storms of July 15, 2000, March 31, 2001, October 29, 2003, and November 20, 2003. These phenomenon has been understood as produced by the perturbation electric fields. The characteristics of the large plasma depletions observed from DMSP F15 and ROCSAT-1 show the formation of steep walls and flat bottom, deepening and widening during the night, and co-locations with plasma bubbles. These observations demonstrate that the large equatorial plasma depletions are origined at the equatorial plasma bubbles. As a widening and deepening mechanism of the bubbles, we suggest the thermospheric compositon change. That is, the molecule-rich air produced by the heating of the polar atmosphere flows along plasma bubbles and additional plasma depletion inside bubbles can create the large depletions. This idea will be validated by presenting the observations and model simulations.
DE: 2415 Equatorial ionosphere
DE: 2437 Ionospheric dynamics
DE: 2439 Ionospheric irregularities
SC: SPA-Aeronomy [SA]
MN: 2005 Joint Assembly