HR: 0800h
AN: SM31A-0401    [Abstracts]
TI: Magnetospheric Convection during Prolonged Intervals with Southward IMF
AU: * Walker, R J
EM: rwalker@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics and Department of Earth and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095-1567 United States
AU: Ashour-Abdalla, M
EM: mabdalla@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics and Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095-1567 United States
AU: El Alaoui, M
EM: mostafa@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095-1567 United States
AB: We have used a global magnetohydrodynamic simulation to investigate magnetospheric convection during a major substorm that occurred during a prolonged interval with southward interplanetary magnetic field on February 13 and 14, 2001. Early in the substorm a near-Earth neutral line located between 20RE and 40RE drove flows earthward and then around the near-Earth obstacle to return magnetic flux to the dayside. The earthward flow lead to increased ionospheric conductance and developed a modest earthward pressure gradient in the inner plasma sheet. Ionospheric line tying and the pressure gradient were sufficient to stop the earthward convection and then reverse it. When the tailward moving flux tube reached the near-Earth neutral line additional reconnection occurred between the tailward moving flux tube and IMF field lines created by lobe reconnection thereby returning flux to the night side tail lobes. Late in the event the new lobe field lines reconnected at the dusk side magnetopause creating additional rapid tailward motion. The tailward flow lead to a reduction in both the ionospheric conductance and near-Earth tail pressure gradient and earthward flow was again established. This sequence repeated at least three times during the interval simulated.
DE: 2744 Magnetotail
DE: 2753 Numerical modeling
DE: 2760 Plasma convection (2463)
DE: 2790 Substorms
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005