HR: 09:02h
AN: SM41B-05    [Abstracts]
TI: Positive/Negative Effects of Solar Wind Density on Auroral Electrojets
AU: * Shue, J
EM: jhshue@jupiter.ss.ncu.edu.tw
AF: Institute of Space Science and Department of Space Sciences, National Central University, 300 Jhongda Road, Jhongli City, 320 Taiwan
AU: * Shue, J
EM: jhshue@jupiter.ss.ncu.edu.tw
AF: Applied Physics Laboratory, The Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD 20723 United States
AU: Kamide, Y
EM: kamide@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, Honohara 3-13, Toyokawa, 442-8507 Japan
AU: Newell, P T
EM: Patrick.Newell@jhuapl.edu
AF: Applied Physics Laboratory, The Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD 20723 United States
AB: Auroral electrojets are a channel of electric currents flowing over the auroral oval. Their development is controlled by magnetic reconnection between the Earth's magnetic field and southward interplanetary magnetic field (IMF) and also by compression of the magnetosphere by enhanced solar wind density and velocity. The subject of effects of solar wind density on auroral electrojets has recently received increasing attention. With ``unbiased'' events in which only the solar wind density varied significantly but other solar wind parameters were relatively constant, we calculated the rates of change of auroral electrojets per unit change of solar wind density. Here we report that the distribution of the rates of change in terms of IMF Bz shows a butterfly pattern. The rates are found to be small for northward IMF. As the southward IMF becomes larger, however, the distribution bifurcates -- one branch extends to positive rates and the other extends to negative rates. It has commonly been believed that the enhanced solar wind density increases the auroral electrojets. Contrary to this expectation, the enhanced solar wind density can decrease the auroral electrojets with high probability.
DE: 2704 Auroral phenomena (2407)
DE: 2708 Current systems (2409)
DE: 2722 Forecasting
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting