HR: 1300h
AN: SM52A-0562    [PDF]
TI: The Dependence of Ring Current Asymmetry on the Phase of Magnetic Storms
AU: Means, E K
AF: Institute of Geophysics and Planetary Physics University of California, Los Angeles, 3845 Slichter Hall PO Box 1567, Los Angeles, CA 90095 United States
AU: * Weygand, J M
EM: jweygand@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics University of California, Los Angeles, 3845 Slichter Hall PO Box 1567, Los Angeles, CA 90095 United States
AU: McPherron, R L
EM: rmcpherron@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics University of California, Los Angeles, 3845 Slichter Hall PO Box 1567, Los Angeles, CA 90095 United States
AU: O'Brien, T P
AF: Space Science Department The Aerospace Corporation, M2-260PO Box 92957, Los Angeles, CA 90009 United States
AB: We utilize the 1-minute resolution Asym and Sym indices for the horizontal component H to study the dependence of ring current asymmetry on the phase of magnetic storms. We find that the ratio Sym-H/Asym-H decreases during the recovery phase suggesting that the ring current is becoming relatively more asymmetric. This result contradicts theoretical expectations and previous experimental results. It suggests that there may be problems with the current operational definition of these quantities. We have examined the possibility that dynamic pressure effects in Sym-H or a constant bias in Asym-H can explain these results. Neither correction can account for our observations. In this paper we will use the original magnetograms and alternative definitions of asymmetry to see if the problem lies in the current procedure for calculating the index. We will illustrate our results using storms from the NSF GEM campaigns that have been numerically modeled.
UR: http://www.igpp.ucla.edu/jweygand
DE: 2708 Current systems (2409)
DE: 2730 Magnetosphere--inner
DE: 2778 Ring current
DE: 2784 Solar wind/magnetosphere interactions
DE: 2788 Storms and substorms
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting