HR: 14:10h
AN: SM53A-03    [Abstracts]
TI: Magnetosheath variations during the storm main phase on November 20, 2003: Evidence for solar wind density control of energy transfer to the magnetosphere
AU: * Kataoka, R
EM: ryuho@nict.go.jp
AF: NASA Goddard Space Flight Center, Code 612.3, Greenbelt, MD 20771 United States
AU: * Kataoka, R
EM: ryuho@nict.go.jp
AF: National Institute of Information and Communications Technology, 4-2-1, Nukui-Kitamachi, Koganei, Tokyo, 184-8795 Japan
AU: Fairfield, D H
EM: donald.H.Fairfield@nasa.gov
AF: NASA Goddard Space Flight Center, Code 612.3, Greenbelt, MD 20771 United States
AU: Sibeck, D G
EM: david.g.Sibeck@nasa.gov
AF: NASA Goddard Space Flight Center, Code 612.3, Greenbelt, MD 20771 United States
AU: Rastaetter, L
EM: lr@waipio.gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Code 612.3, Greenbelt, MD 20771 United States
AU: Fok, M
EM: mei-ching.h.fok@nasa.gov
AF: NASA Goddard Space Flight Center, Code 612.3, Greenbelt, MD 20771 United States
AU: Nagatsuma, T
EM: tnagatsu@nict.go.jp
AF: National Institute of Information and Communications Technology, 4-2-1, Nukui-Kitamachi, Koganei, Tokyo, 184-8795 Japan
AU: Ebihara, Y
EM: ebihara@nipr.ac.jp
AF: National Institute of Polar Research, 1-9-10 Kaga, Itabashi, Tokyo, 173-8515 Japan
AB: Energy transfer from the solar wind into the magnetosphere and ionosphere is controlled by the southward magnetic field in the magnetosheath which under normal high Mach number conditions is about four times the solar wind southward field. In a low Mach number regime, however, the magnetosheath compression is diminished by a low solar wind density when the magnetic field remains steady. When magnetic clouds with extremely strong magnetic field cause severe geomagnetic storms under such low Mach number conditions, the density control of the energy transfer is expected to be important in understanding ring current evolution. Here we show evidence for such a density effect using in-situ observation by the GOES and Cluster spacecraft in the magnetosheath during the main phase of the super storm on November 20, 2003. Results from a global magnetohydrodynamic (MHD) simulation with an embedded ring current model also support this density effect.
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 2728 Magnetosheath
DE: 2753 Numerical modeling
DE: 2784 Solar wind/magnetosphere interactions
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005