HR: 0800h
AN: SM31A-0400    [Abstracts]
TI: Propagation of Field and Plasma Disturbances in the Magnetotail During Substorms: Case Study
AU: * Lin, N
EM: nlin@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, Berkeley, CA 94720 United States
AU: Bonnell, J W
EM: jbonnell@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, Berkeley, CA 94720 United States
AU: Hull, A J
EM: ahull@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, Berkeley, CA 94720 United States
AU: Lee, E S
EM: eslee@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, Berkeley, CA 94720 United States
AU: McFadden, J P
EM: mcfadden@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, Berkeley, CA 94720 United States
AU: Mozer, F S
EM: fmozer@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, Berkeley, CA 94720 United States
AU: Parks, G K
EM: parks@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, Berkeley, CA 94720 United States
AU: Wilber, M
EM: wilber@ssl.berkeley.edu
AF: Space Sciences Laboratory, UC Berkeley, Berkeley, CA 94720 United States
AU: Lucek, E A
EM: e.lucek@imperial.ac.uk
AF: Space and Atmospheric Physics, Imperial College, London, SW7 2BZ United Kingdom
AU: Russell, C T
EM: ctrussel@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, UCLA, Los Angeles, CA 90095 United States
AU: Scudder, J D
EM: jack-scudder@uiowa.edu
AF: Physics and Astronomy Department, University of Iowa, Iowa City, IA 52242 United States
AB: Substorm studies have shown that there exist two active regions in the magnetotail during substorms: the inner magnetotail region (~ 6 - 10 Re) and the midtail region (~ 15 - 30 Re). Sudden occurrences of large disturbances and high speed plasma flows which are associated with substorms have been observed in both mid-tail and near tail regions. In an attempt to understand the relationship between these disturbances we conduct a conjunction study which correlates the observations of variations of plasma and electric and magnetic fields in the two regions. The observations were made by Cluster at ~ 17-19 Re and Polar at ~ 8-9 Re in the magnetotail, and we require Polar to be in close radial and azimuthal alignments with Cluster. We will present a few examples of such studies. The results from the few cases suggest the source regions of sudden large disturbances exist at various distances in the tail. Comparison of observed signatures in these events with substorm models will be made. For example, an event on Oct 14, 2002, between 1700 and 1730 UT, shows that sudden increases in the ion velocity were observed in the earthward direction at both Polar and Cluster, with maximum velocity of ~800 km/s at Cluster observed a few minutes earlier than that at Polar. This suggests that the source of the disturbances is located tailward of the Cluster spacecraft. While the ions streaming at Cluster mostly along field lines, the ion flows at Polar seem to be consistent with EXB flow. At the onset of the disturbance dipolarization was observed at Polar accompanying by a duskward E field, signatures which may be consistent with the breaking of earthward flows in near tail. Uncertainties in such conjunction study will also be discussed.
DE: 2740 Magnetospheric configuration and dynamics
DE: 2744 Magnetotail
DE: 2790 Substorms
DE: 7807 Charged particle motion and acceleration
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005