HR: 1330h
AN: SM32A-1139    [PDF]
TI: Three-Dimensional MHD Simulation of Current Sheet Thinning During the Growth Phase of Magnetospheric Substorms
AU: * Hall, F
EM: fh@why.gi.alaska.edu
AF: Geophysical Institute University of Alaska, Fairbanks, 903 Koyukuk Drive P.O. Box 757320, Fairbanks, AK 99775-7320 United States
AU: Otto, A
EM: ao@how.gi.alaska.edu
AF: Geophysical Institute University of Alaska, Fairbanks, 903 Koyukuk Drive P.O. Box 757320, Fairbanks, AK 99775-7320 United States
AB: We have studied the formation of thin current sheets during the growth phase of magnetospheric substorms. Our approach is based on the conservation of entropy of magnetic flux tubes during the slow quasi-static evolution of the magnetosphere seen during the growth phase. The growth phase is initiated by the erosion of closed dayside magnetic flux. This flux is replenished by convection of closed magnetic flux from the near-Earth tail region to the dayside. However, this process of magnetic flux replenishment is subject to the entropy constraints imposed on the slow quasi-static convection of magnetic flux tubes from the mid- and far-tail regions, first identified by {\it Erickson and Wolf\/} (1980). We argue that the depletion of flux from a finite reservoir in the near-Earth tail region leads to the observed current sheet thinning. We use three-dimensional MHD simulations to model the formation of the thin current sheet in the near-Earth region during the late growth phase of substorms.
DE: 2740 Magnetospheric configuration and dynamics
DE: 2744 Magnetotail
DE: 2753 Numerical modeling
DE: 2760 Plasma convection
DE: 2788 Storms and substorms
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting