HR: 16:45h
AN: SM54A-04    [Abstracts]
TI: Geoeffectiveness of Magnetic Storms Driven by Corotating Interaction Regions (CIRs) and Ejecta-Related Events
AU: * Turner, N E
EM: neturner@fit.edu
AF: Florida Institute of Technology, Physics Dept 150 W University Blvd, Melbourne, FL 32901
AU: Mitchell, E J
EM: mitchele@fit.edu
AF: Florida Institute of Technology, Physics Dept 150 W University Blvd, Melbourne, FL 32901
AU: Knipp, D J
EM: delores.knipp@usafa.af.mil
AF: US Air Force Academy, Physics Dept, USAFA, CO 80840
AB: We investigate the energetics of magnetic storms associated with corotating interaction regions (CIRs). We analyze storms driven by CIRs and compare to those driven by ejecta-related events to determine how they differ in overall properties and in particular in their distribution of energy. To compare these different types of events, we look at events with comparable input parameters such as the epsilon parameter and note the properties of the resulting storms. We estimate the energy output by looking at the ring current and ionospheric Joule heating and auroral precipitation derived from Dst* and the PC index. In general, ejecta-driven storms seem to produce more intense events, as parameterized by Dst*, but they are not as long-lasting, and in many cases do not deposit the same amount of energy. This is observed even for events which are estimated to have similar total input quantities, such as epsilon. This may be related to the high speed of the solar wind, in that an increased magnetosonic Mach number may influence the reconnection rate and therefore the coupling. Additionally, we find that the energy output in the recovery phase of CIR-driven storms correlates highly with energy input during recovery, suggesting that the system is still being driven by the solar wind in recovery. This is different from what we find with ejecta-driven storms, which depend more on input energy from the main phase. Additionally, we find the efficiency of the coupling to vary greatly from CIR to ejecta-driven storms, with the CIR storms coupling substantially more efficiently.
DE: 2784 Solar wind/magnetosphere interactions
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005