HR: 08:15h
AN: SM31A-02    [PDF]
TI: Near-Earth Magnetotail Reconnection and Plasmoid Formation in Connection With a Substorm Onset on 27 August 2001
AU: * Eriksson, S
EM: eriksson@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303-7814 United States
AU: \Oieroset, M
EM: oieroset@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Centennial Dr at Grizzly Peak Blvd, Berkeley, CA 94720-7450 United States
AU: Baker, D N
EM: daniel.baker@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303-7814 United States
AU: McPherron, R L
EM: rmcpherron@igpp.ucla.edu
AF: Institute of Geophysical and Planetary Physics, University of California, 405 Hilgard Avenue, Los Angeles, CA 90024-1567 United States
AU: Monk, S
EM: monk@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303-7814 United States
AU: Dunlop, M W
EM: M.W.Dunlop@rl.ac.uk
AF: Space Sciences Division, Rutherford Appleton Laboratory, DIDCOT, Chilton, Oxfordshire, OX11 0QX United Kingdom
AU: R\`{e}me, H
EM: henri.reme@cesr.fr
AF: Centre d'Etude Spatiale des Rayonnements, 9 Ave Colonel Roche, Toulouse, 31029 France
AU: Sarris, T E
EM: sarris@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303-7814 United States
AU: Shen, C
EM: sc@center.cssar.ac.cn
AF: Laboratory for Space Weather, Center for Space Science and Applied Research, No.1, Nanertiao, Zhongguancun, Haidian District, Beijing, 100080 China
AU: Balogh, A
EM: a.balogh@ic.ac.uk
AF: Physics Department, The Blackett Laboratory, Imperial College, Prince Consort Road, London, SW7 2BZ United Kingdom
AB: We have examined the magnetic field and ion velocity data from the Cluster spacecraft on 27 August 2001 when the spacecraft were located in the postmidnight magnetotail at $x_{GSM}=-19 R_{E}$ and $y_{GSM}=-2 R_{E}$. Fast earthward flows were recorded at both Cluster sc1 and sc3 $\sim$32 min prior to a substorm onset at $\sim$0401 UT, when enhanced tailward flows were detected at both spacecraft. Cluster sc3 also detects earthward directed flows $\sim$30 min after the onset. These plasma flows are suggestive of slow-mode shocks in a Petschek-type reconnection layer. The negative $B_{y}$ component of the observed magnetic field coincident with high-speed tailward flows at substorm onset strongly suggest the formation and ejection of a plasmoid. We apply a curvature analysis technique on the magnetic field data to investigate the topology of the plasmoid during its evolution. The indication that reconnection is active prior to the downtail release of the plasmoid at substorm onset may be interpreted as a semi-continuous erosion of magnetic fields in the near-Earth magnetotail region and may provide us with information on the dynamic evolution of the near-Earth neutral line (NENL) to the point of plasmoid release.
DE: 2740 Magnetospheric configuration and dynamics
DE: 2744 Magnetotail
DE: 2788 Storms and substorms
DE: 7835 Magnetic reconnection
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting