HR: 16:35h
AN: SM24A-03    [Abstracts]
TI: Earthward Flowing Plasmoid: Structure and Its Related Auroral Signature
AU: Fritz, T
EM: fritz@bu.edu
AF: Center For Space Physics, Boston University, 725 Commonwealth Ave, Boston, 02215 United States
AU: * Zong, Q
EM: zong@bu.edu
AF: Center For Space Physics, Boston University, 725 Commonwealth Ave, Boston, 02215 United States
AU: Baker, D
SM24A-03 AF: Lab. for Atmos. and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, 80303 United States
AU: Goldstein, M
SM24A-03 AF: NASA Goddard Space Flight Center, Greenbelt, MD, Greenbelt, 20770 United States
AU: Daly, P
SM24A-03 AF: MPS, Germany, Max-Planck Strasse, Katlenburg-Lindau, 37191 Germany
AU: Fu, S
EM: suiyanfu@pku.edu.cn
AF: ISPAT, Peking University, Beijing, 100871 China
AU: Frey, H
SM24A-03 AF: Space Science Laboratory, University of California, Berkeley, 7 Gauss Way, Berkeley, 94720 United States
AU: Balogh, A
SM24A-03 AF: Space and Atmospheric Physics Group, Imperial College, London, UK, London, UK, London, SW7 2BW United Kingdom
AU: Reme, H
SM24A-03 AF: Centre dEtude Spatiale des Rayonnements, France, Toulouse, Codex 4 France
AB: An earthward-moving plasmoid on Oct. 28, 2002 has been observed by the Cluster spacecraft with simultaneous auroral viewing by IMAGE satellite. This offers the opportunity to ascertain the optical signature and its evolution in the ionosphere of an earthward moving plasmoid for the first time. The intensity of the current in the center of the plasmoid is found to be weaker than that in the adjacent region. Also, the directions of the current in the central part of the plasmoid are different from the background cross-tail current: they are more field-aligned. The calculation of J × B demonstrates that the plasmoid is not a highly force-free structure. The unusually large bipolar electric field found in the plasmoid (peak to peak values 6 and 8 mV/m) can be explained as a dawn-dusk polarization electric field is generated to enhance the flows as predicted in the bubble model. Broad-band electrostatic noise (BEN) and bursty electrostatic electron cyclotron waves are found inside the plasmoid which are closely associated with the acceleration of the plasma. Furthermore, IMAGE data show the auroral forms moving to lower latitude, which is when an earthward moving plasmoid observed by the Cluster spacecraft. Such an equatorward auroral motion is consistent well with the observed earthward moving plasmoid.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2700 MAGNETOSPHERIC PHYSICS (6939)
DE: 2704 Auroral phenomena (2407)
DE: 2744 Magnetotail
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005