HR: 16:00h
AN: SM54A-01    [Abstracts]
TI: Multiscale Complexity Reflects Substorm Dynamics: Toward Designing a New Auroral Index
AU: * Uritsky, V M
EM: vuritsky@phas.ucalgary.ca
AF: Department of Physics and Astronomy, University of Calgary, SB605, University Drive NW, Calgary, AB T2N 1N4, Canada
AU: Donovan, E
EM: eric@phys.ucalgary.ca
AF: Department of Physics and Astronomy, University of Calgary, SB605, University Drive NW, Calgary, AB T2N 1N4, Canada
AU: Klimas, A J
EM: alex.klimas@nasa.gov
AF: UMBC/Goddard Space Flight Center, Code 673, Greenbelt, MD 20771, United States
AB: Earth's magnetosphere is known to generate complex spatiotemporal patterns of activity reflecting its strongly nonlinear response to the solar wind driver as well as the intrinsic stochasticity of plasma phenomena in the near-Earth environment. On average, and over large time scales involving many typical susbstorm loading- unloading times, this activity tends to self-organize into a nearly perfect scale-invariant dynamical state reminiscent of that in critical "avalanching" sandpile models. In this talk, we present evidence that on shorter time scales the magnetosphere exhibits distinct deviations from the scale-free statistics that correlate with the development of the substorm. Based on an analysis of auroral images from POLAR and IMAGE satellites, we propose a set of scaling parameters of auroral activity that can provide some essential new information on substorm phases and location and have the potential of being a new dynamical measure of the geoeffectiveness of the solar wind input under a variety of IMF conditions. Our results confirm that the magnetosphere operates as a critical avalanching system on a global scale, but they also show that the individual energy release events underlying this critical state seem to be shaped by a variety of inhomogeneous and transient processes violating most of the symmetries assumed in simplistic sandpile models.
UR: http://phas.ucalgary.ca/~vuritsky/SM07 DE: 2407 Auroral ionosphere (2704)
DE: 2784 Solar wind/magnetosphere interactions
DE: 2788 Magnetic storms and substorms (7954)
DE: 3265 Stochastic processes (3235, 4468, 4475, 7857)
DE: 4430 Complex systems
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting