HR: 1340h
AN: SM43B-1329    [Abstracts]
TI: Variations of Substorm Recovery Time Scales
AU: * Fillingim, M O
EM: matt@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, 7 Gauss Way, Berkeley, CA 94720, United States
AU: Chua, D
AF: Space Science Division, Naval Research Laboratory, Washington, DC 20375, United States
AU: Germany, G A
AF: Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 35899, United States
AU: Spann, J F
AF: NASA, Marshall Space Flight Center, Huntsville, AL 35812, United States
AB: Previous work [Chua et al., 2004] computed the substorm recovery time scale for over three hundred substorms observed by the Polar Ultraviolet Imager (UVI). When sorted according to season, the substorm recovery times were well ordered by whether or not the nightside auroral region was sunlit: substorms occurring in the winter and equinox periods had similar recovery time scales which were both roughly a factor of two longer than that for summer when the auroral oval was sunlit. These results strongly suggest that simultaneous auroral intensifications in the northern and southern hemispheres develop differently during solstice conditions. We expect the auroral breakup in the dark (winter) hemisphere to be more intense and longer lived than that observed in the sunlit (summer) hemisphere. This also implies that more energy is deposited by electron precipitation in the winter hemisphere than in the summer one during a substorm. Here we extend this previous work by including a similar number of substorms observed by IMAGE Far Ultraviolet Imager (FUV) as well as simultaneous, conjugate auroral substorm observations by Polar UVI and the IMAGE FUV. The observed hemispheric asymmetry and non-conjugacy of auroral substorms is consistent with the suppression of discrete aurora in sunlight and highlights the importance of ionospheric conductivity plays in global-scale dynamics of the aurora and in magnetosphere-ionosphere coupling.
UR: http://sprg.ssl.berkeley.edu/matt/AGU2007/
DE: 2704 Auroral phenomena (2407)
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 2740 Magnetospheric configuration and dynamics
DE: 2790 Substorms
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting