HR: 11:50h
AN: SM31E-07    [PDF]
TI: Near-Earth Reconnection Confined in the Plasmasheet during the Substorm Growth Phase: A Study of the November 24, 1996, Event
AU: Ueno, G
EM: gen@ism.ac.jp
AF: The Institute of Statistical Mathematics, 4-6-7, Minami-Azabu, Minato-ku, Tokyo, 106-8569 Japan
AU: * Ohtani, S
EM: ohtani@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd., Laurel, 20723-6099 United States
AU: Yamaguchi, R
EM: ruiy@ism.ac.jp
AF: The Institute of Statistical Mathematics, 4-6-7, Minami-Azabu, Minato-ku, Tokyo, 106-8569 Japan
AU: Creutzberg, F
EM: Fokke.creutzberg@sp-agency.ca
AF: KeoMetrics, 9 Massey Lane, Gloucester, ON K1J 6C7 Canada
AU: Singer, H
EM: Howard.Singer@noaa.gov
AF: NOAA R/E/SE, 325 Broadway, Boulder, CO 80303-3328 United States
AU: Mukai, T
EM: mukai@stp.isas.ac.jp
AF: Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, 229-8510 Japan
AU: Yumoto, K
EM: yumoto@geo.kyushu-u.ac.jp
AF: Space Environment Research Center, Kyushu Univ., 6-10-1 Hakozaki, Fukuoka, 812-8581 Japan
AB: The present study examines a substorm event of November 24, 1996, with an emphasis on magnetic field and plasma flow measurements in the magnetotail during the growth phase. The unique and most intriguing feature of this event is a systematic change of the flow direction from earthward to tailward observed by the Geotail satellite at X = -21 Re. Good correlation between Vx and Bx suggests that observed variations of the flow velocity were spatial rather than temporal and that the earthward and tailward flows lasted at least 9 and 5 min, respectively. The signs of Bz and By variations also changed systematically along with the sign of Vx, which suggests that the observed flow reversal was caused by the earthward movement of a neutral line. This neutral line might be formed in association with a preceding pseudobreakup, and it is inferred that the associated reconnection did not reach the lobe magnetic field. Interestingly, during the interval of the flow reversal, other satellites observed typical growth-phase features. Geosynchronous magnetic field continued to be stretched in the midnight sector. The Interball and IMP-8 satellites observed continuous increase of the lobe field strength at X = -20 and -34 Re, respectively, in the premidnight sector. It is therefore concluded that the tail current intensification during the growth phase is a global process, whereas the near-Earth reconnection is a local process and at its early stage, it can proceed independently from the overall storage of the tail magnetic energy.
DE: 2704 Auroral phenomena (2407)
DE: 2708 Current systems (2409)
DE: 2744 Magnetotail
DE: 2764 Plasma sheet
DE: 2788 Storms and substorms
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting