HR: 14:20h
AN: SM52D-03    [PDF]
TI: Evolution of current systems in the magnetosphere-ionosphere during the transition from northward to southward IMF
AU: * Hashimoto, K K
EM: hashimoto@crl.go.jp
AF: Communications Research Laboratory, 4-2-1, Nukui-kita, Koganei, Tokyo, 184-8795 Japan
AB: In order to examine how the current systems evolve in the magnetosphere and ionosphere, we have compared plasma flows in the dayside polar cap and the global DP2 current during the transition from northward to southward of the interplanetary magnetic field (IMF) with two events:November 17, 1996 and March 26, 1998. DP2 magnetic field perturbations instantaneously begin from the polar cap to the dip-equator on the dayside indicating development of the global ionospheric currents that connect to the Region-1 Field-aligned currents (FACs). During the events, the SuperDARN measurements in the polar region showed dramatic changes in the ionospheric plasma flow from the multi-cell convection pattern associated with the northward IMF to the large scale two-cell pattern associated with the southward IMF. The dusk cell in the two-cell convection emerged and developed around a center of 15 MLT at 78 degrees magnetic latitude, as the reverse cells in the multi-cell pattern disappeared. We found that the reverse convection cells remained in the polar cap for the first six minutes while the DP2 current were developing. The observational results suggest that it takes about six minutes for the potential electric field of the Region-1 FACs to surpass that of the NBZ FACs in the polar cap when the IMF turns southward.
DE: 2411 Electric fields (2712)
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2475 Polar cap ionosphere
DE: 2708 Current systems (2409)
DE: 2760 Plasma convection
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting