HR: 17:00h
AN: SM22D-05    [PDF]
TI: The Relative Timing of Substorm Onset Phenomena
AU: * Kepko, E L
EM: lkepko@bu.edu
AF: Boston University, Center for Space Physics 725 Commonwealth Ave., Boston, MA 02215 United States
AU: Kivelson, M G
EM: mkivelson@igpp.ucla.edu
AF: UCLA, Dept. of Earth and Space Sciences, Los Angeles, CA 90024 United States
AU: McPherron, R L
EM: rmcpherron@igpp.ucla.edu
AF: UCLA, Dept. of Earth and Space Sciences, Los Angeles, CA 90024 United States
AU: Spence, H E
EM: spence@bu.edu
AF: Boston University, Center for Space Physics 725 Commonwealth Ave., Boston, MA 02215 United States
AB: Current debate over the initiation of a magnetospheric substorm centers on two viable onset models. One model is that substorm onset begins with disruption of the near-Earth crosstail current. The other possibility is that onset begins with magnetic reconnection in the midtail plasmasheet, and that subsequent dynamics are driven by convective flow bursts. Each model predicts a different temporal ordering of onset phenomena. We present the results of event studies where we examine the temporal ordering of convective plasma flow in the plasmasheet, Pi2 pulsations, and auroral arc brightening. Using the causal link between midtail plasma flows and low latitude Pi2 pulsations and the relative timing of phenomena we show that the observed sequence of events disagrees with predictions of CD models. We then show that the observations lend strong support to the flow-burst model of magnetotail dynamics.
DE: 2740 Magnetospheric configuration and dynamics
DE: 2744 Magnetotail
DE: 2764 Plasma sheet
DE: 2788 Storms and substorms
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting