HR: 08:35h
AN: SM21B-03    [Abstracts]
TI: Coordinated Polar Spacecraft, Geosynchronous Spacecraft, and Ground-based Observations of Magnetopause Processes and Their Coupling to the Ionosphere
AU: * Le, G
EM: Guan.Le@nasa.gov
AF: NASA/GSFC, Laboratory for Extraterrestrial Physics, NASA/GSFC, Greenbelt, MD 20771 United States
AU: Chen, S
EM: shchen@lepvax.gsfc.nasa.gov
AF: USRA at NASA/GSFC, Universities Space Research Association, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Zheng, Y
EM: yihua.zheng@gsfc.nasa.gov
AF: NRC at NASA/GSFC, NRC, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Russell, C T
EM: ctrussell@igpp.ucla.edu
AF: UCLA, IGPP/UCLA, Los Angeles, CA 90095-1567 United States
AU: Slavin, J A
EM: James.A.Slavin@nasa.gov
AF: NASA/GSFC, Laboratory for Extraterrestrial Physics, NASA/GSFC, Greenbelt, MD 20771 United States
AU: Huang, C
EM: cshuang@haystack.mit.edu
AF: MIT Haystack Observatory, MIT Haystack Observatory, Westford, MA 01886 United States
AU: Petrinec, S S
EM: petrinec@star.spasci.com
AF: Lockheed Martin, Space Physics Laboratory, Lockheed Martin Advanced Technology Center, Palo Alto, CA 94304-1187 United States
AU: Moore, T E
EM: Thomas.E.Moore@nasa.gov
AF: NASA/GSFC, Laboratory for Extraterrestrial Physics, NASA/GSFC, Greenbelt, MD 20771 United States
AU: Samson, J
EM: samson@phys.ualberta.ca
AF: University of Alberta, Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1 Canada
AU: Singer, H J
EM: Howard.Singer@noaa.gov
AF: NOAA/SEC, NOAA Space Environment Center, Boulder, CO 80305 United States
AU: Yumoto, K
EM: yumoto@serc.kyushu-u.ac.jp
AF: Kyushu University, Space Environment Research Center, Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
AB: In this paper, we present in situ observations of surface waves at the magnetopause and oscillatory magnetospheric field lines, and coordinated observations Pc5 waves at geosynchronous orbit by the GOES spacecraft, and on the ground by CANOPUS and 210§ Magnetic Meridian (210MM) magnetometer arrays. On February 7, 2002 during a high-speed solar wind stream, the Polar spacecraft was skimming the magnetopause in a post-noon meridian plane for ~ 3 hours. During this interval, it made two short excursions and a few partial crossings into the magnetosheath and observed quasi-periodic cold ion bursts in the region adjacent to the magnetopause current layer. The multiple magnetopause crossings as well as the velocity of the cold ion bursts indicate that the magnetopause was oscillating with about 6 minute period. Simultaneous observations of Pc5 waves at geosynchronous orbit by the GOES spacecraft and on the ground by the CANOPUS magnetometer array reveal that these magnetospheric pulsations were forced oscillations of magnetic field lines directly driven by the magnetopause oscillations. The magnetospheric pulsations occurred only in a limited longitudinal region in the post-noon dayside sector, and were not a global phenomenon as one would expect for global field line resonance. Thus, the magnetopause oscillations at the source were also limited to a localized region spanning about 4 hours in local time. These observations suggest that it is unlikely that the Kelvin-Helmholz instability and/or fluctuations in the solar wind dynamic pressure were the direct driving mechanisms for the observed boundary oscillations. Instead, the likely mechanism for the localized boundary oscillations was pulsed reconnection at the magnetopause occurring along the X-line extending over the same 4-hour region. The Pc5 band pressure fluctuations commonly seen in high-speed solar wind streams may modulate the reconnection rate as an indirect cause of the observed Pc5 pulsations.
DE: 2724 Magnetopause, cusp, and boundary layers
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2752 MHD waves and instabilities
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting