HR: 11:15h
AN: SM51D-04    [PDF]
TI: Interhemispheric conjugate observations of ionospheric convection flows in the dayside high-latitude regions
AU: * Kataoka, R
EM: ryuho@pat.geophys.tohoku.ac.jp
AF: Department of Geophysics, Tohoku University, Aoba, Sendai, 980-8578 Japan
AU: Fukunishi, H
EM: fuku@pat.geophys.tohoku.ac.jp
AF: Department of Geophysics, Tohoku University, Aoba, Sendai, 980-8578 Japan
AU: Hosokawa, K
EM: hosokawa@ice.uec.ac.jp
AF: The University of Electro-Communications, 1-5-1, Chofugaoka, Chofu, 182-8585 Japan
AU: Yukimatu, A S
EM: aguS@uap.nipr.ac.jp
AF: National Institute of Polar Research, 1-9-10, Kaga, Itabashi, 173-8515 Japan
AU: Sato, N
EM: nsato@nipr.ac.jp
AF: National Institute of Polar Research, 1-9-10, Kaga, Itabashi, 173-8515 Japan
AB: Interhemispheric conjugate observations of ionospheric convection flows are essential for understanding the electrodynamics in the dayside high-latitude regions, particularly in the cusp and the open/closed field line boundary region. We investigate the SuperDARN data for this purpose. Merged vectors obtained from pairs of radars are calculated using the common program data during the 8-year period of 1995-2002. We select 29 events in which a large number of merged vectors are obtained by coverage of pairs of conjugate radars. Most events occurred near equinox under the southward IMF conditions. This is consistent with a fact that the generation of ionospheric irregularities is affected by daylight high diffusion rates and enhancements of convection electric field. Interhemispheric convection patterns are consistent with the Heppner-Maynard pattern when the IMF is stable for $>$30 min. It is found that convection flows and vorticities tend to be weak in the sunlit region in the vicinity of the open/closed field line boundary. This may reflect an asymmetry of the cusp properties in the northern and southern hemispheres due to ionospheric conductivity differences. Considering these result, we discuss the three dimensional current system producing the interhemispheric convection patterns in the dayside high-latitude region.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2463 Plasma convection
DE: 2708 Current systems (2409)
DE: 2712 Electric fields (2411)
DE: 2724 Magnetopause, cusp, and boundary layers
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting