HR: 10:35h
AN: SA12A-02 INVITED     [Abstracts]
TI: Ring Current Coupling with the Radiation Belt, Plasmasphere and the Subauroral Ionosphere
AU: * Fok, M
EM: mei-ching.h.fok@nasa.gov
AF: NASA Goddard Space Flight Center, Code 612.2, Greenbelt, MD 20771 United States
AU: Ebihara, Y
EM: ebihara@nipr.ac.jp
AF: National Institute of Polar Research, 1-9-10 Kaga, Itabashi-ku, Tokyo, 173-8515 Japan
AU: Moore, T E
EM: thomas.e.moore@nasa.gov
AF: NASA Goddard Space Flight Center, Code 612.2, Greenbelt, MD 20771 United States
AB: The ring current is the key element of geospace storms and its effects are manifest both in the magnetosphere and ionosphere. During major storms, the magnetic field generated by the ring current greatly deforms the earth's field even at low L shells of 3-4. These distortions and related fluctuations of the magnetic field alter the transport of radiation belt particles and influence their dynamics, including the filling of the slot region. The ring current pressure distribution reacts back on the forces of global convection that drive it, in conjunction with electrically-coupled ionospheric motions. One resulting storm feature is the subauroral polarization stream (SAPS) observed in the ionosphere in the dusk-midnight sector equatorward of the auroral precipitation. The strong westward drift associated with the SAPS field sweeps away the cold plasmas in the plasmasphere and sharpens the duskside plasmaspause. Variations in ring current sources also produce changes or instability in the plasmasphere. We will present modeling results predicting ring current effects on the radiation belt, plasmasphere and the subauroral ionosphere during several great storms. They all lead to the conclusion that understanding of the dynamic ring current is crucial in understanding magnetic storms and their effectiveness in generating enhanced radiation belts.
DE: 2730 Magnetosphere: inner
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 2774 Radiation belts
DE: 2778 Ring current
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005