HR: 1340h
AN: SA33A-1128    [Abstracts]
TI: ROCSAT-1 Observations of Quiet-time Low-latitude Plasma Bubbles
AU: * Ho, M
EM: mrho@jupiter.ss.ncu.edu.tw
AF: Institute of Space Science, National Central University, Institute of Space Science, National Central University, Chung-Li, 320-01 Taiwan
AU: Yeh, H
EM: yeh@jupiter.ss.ncu.edu.tw
AF: Institute of Space Science, National Central University, Institute of Space Science, National Central University, Chung-Li, 320-01 Taiwan
AU: Fu, C
AF: Institute of Space Science, National Central University, Institute of Space Science, National Central University, Chung-Li, 320-01 Taiwan
AB: Plasma bubbles observed by the IPEI payload of the ROCSAT-1 satellite during the solar maximum years of 2000 and 2001 are used to study the statistical features under quiet geomagnetic conditions ($Kp < 3$). We examine the occurrence probability and morphology of the bubbles, which are found to depend on local time, season, and magnetic field configuration (longitude). During the solstices the longitudinal variations of bubble structures were fairly pronounced. In particular, during the northern hemisphere winter, the bubbles were mainly found in the South Atlantic Anomaly (SAA) longitude sector ($300^o-360^o$E), where the geomagnetic declinations are mostly negative. Such longitudinal preference of bubble events can be explained if we consider the effects of the neutral-wind dynamo electric fields and the horizontal density gradients (zonal and meridional) on the growth rate of the generalized Rayleigh-Taylor instability.
DE: 2411 Electric fields (2712)
DE: 2415 Equatorial ionosphere
DE: 2439 Ionospheric irregularities
DE: 2481 Topside ionosphere
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting