HR: 16:30h
AN: SA22C-03    [PDF]
TI: Simultaneous Observations of Equatorial Plasma Depletion by IMAGE and ROCSAT-1 Satellites
AU: * Lin, C S
EM: clin@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 United States
AU: Immel, T
EM: immel@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, CA 94720 United States
AU: Yeh, H
EM: yeh@jupiter.ss.ncu.edu.tw
AF: Institute of Space Science, National Central University, Chung-Li, 300 Taiwan
AU: Mende, S B
EM: mende@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, CA 94720 United States
AU: Burch, J L
EM: jburch@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 United States
AB: Simultaneous observations of the equatorial ionosphere by ROCSAT-1 and IMAGE satellites have been used to study plasma characteristics of equatorial plasma bubbles. IMAGE Far-ultraviolet (FUV) nighttime images have indicated signatures of depression in the brightness of equatorial airglow arcs. Using the list of airglow brightness depression events observed by IMAGE, we surveyed ROCSAT-1 IPEI data for simultaneous plasma observations in the same local time. Our preliminary investigation has indicated that features of brightness depression seen in FUV images were correlated with equatorial plasma bubbles detected by ROCSAT-1 at 600 km altitude. Successive FUV images are averaged to produce a keogram with UT versus longitude, which is then used to deduce drift velocity for plasma density depletions. For the simultaneous observation events of plasma density depletion, we compare the ion drift velocities measured by ROCSAT-1 with the drift speed determined from the FUV keogram. We examine the relationship among the drifting speed of airglow brightness depression, the ion velocity inside equatorial plasma bubbles, and the ion velocity of the background plasma. The analysis results are used to answer questions about whether the bubbles are drifting faster than the ambient plasma, and how equatorial plasma bubbles evolve as they drift.
DE: 2415 Equatorial ionosphere
DE: 2439 Ionospheric irregularities
SC: SPA - Aeronomy [SA]
MN: 2003 Fall Meeting