HR: 0800h
AN: SM51C-0396    [Abstracts]
TI: Statistical Analysis of Flux Transfer Events Simultaneously Observed by ISEE-1 and ISEE-2
AU: * Kawano, H
EM: hkawano@geo.kyushu-u.ac.jp
AF: Department of Earth and Planetary Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
AU: Russell, C T
EM: ctrussel@igpp.ucla.edu
AF: UCLA, Institute of Geophysics and Planetary Physics, Box 951567, Los Angeles, CA 90095-1567 United States
AB: Flux transfer events (FTEs) are transient phenomena (duration: a few to several minutes) observed near the magnetopause, characterized by bipolar perturbations in the magnetic field component perpendicular to the magnetopause ($B_N$ below). FTEs are generally thought to be the results of transient reconnections at the magnetopause. There exist many reports in literature on FTEs. However, so far there exist only limited number of reports doing statistical analyses on the directions of motions of FTEs, because one satellite is not sufficient to clarify the spatial structures and the directions of motions of FTEs. To address the directions of motions of FTEs, in this paper we present a statistical analysis of FTEs simultaneously observed by two satellites ISEE-1 and ISEE-2, which made observations for continuous ten years (1978-1987). Two-point observation does not 100% resolve the direction of motion; we cover it by large-scale statistics ($>$600 events) of the ten-years data of ISEE. For each FTE we have determined the time lag from ISEE-1 to \mbox{ISEE-2} as that which maximizes the correlation function between $B_N$'s at ISEE-1 and ISEE-2. We have then examined the time lags as a function of the spatial distance from ISEE-1 to ISEE-2. The results include the following. The time lag tends to be proportional to the longitudinal distance, consistent with east-west motions away from the subsolar point. On the other hand, the time lag shows little correlation with the latitudinal distance. The significant east-west motion suggests that FTEs are unlikely to have a structure whose longitudinal scale is much longer than its latitudinal scale; a flux tube structure is more likely for FTEs than a long-X-line type structure.
DE: 2724 Magnetopause, cusp, and boundary layers
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting