HR: 1400h
AN: SM53A-08    [Abstracts]
TI: Spatio-temporal dynamics of the magnetosphere during geospace storms
AU: * Chen, J
EM: chenjian@astro.umd.edu
AF: University of Maryland, Department of Astronomy, College Park, MD 20742, United States
AU: Sharma, A
EM: ssh@astro.umd.edu
AF: University of Maryland, Department of Astronomy, College Park, MD 20742, United States
AU: Edwards, J W
EM: jonathan.edwards@baesystems.com
AF: BAE Systems, BAE Systems, Washington, DC , United States
AU: Shao, X
EM: xshcn@astro.umd.edu
AF: University of Maryland, Department of Astronomy, College Park, MD 20742, United States
AU: Kamide, Y
EM: kamide@stelab.nagoya-u.ac.jp
AF: Nagoya University, Solar Terrestrial Environment Laboratory, Nagoya, Japan
AB: The magnetospheric response to strong driving by the solar wind is highly structured, and spatially resolved data are essential for the understanding of the spatio-temporal dynamics. The global features of the magnetosphere have been studied extensively using nonlinear dynamical techniques. A database of the solar wind data from ISEE3 and IMP8 spacecraft, and ground-based magnetometer data from high latitude stations [Kamide et al., JGR, 17,705, 1998] is used to study the magnetospheric response to solar wind variables by mutual information functions. A key feature of the mutual information function is its ability to bring out the linear as well as nonlinear correlations and such functions are needed to study the magnetospheric dynamics, which is inherently nonlinear. The minimum window length required for computing robust functions is found to be about 6 hrs. Another window length of 24 hrs is used in these studies to analyze the dynamics on longer time scales. The spreads in the average mutual information show strong correlations with the solar wind convective electric field and the sudden changes in the dynamic pressure. The time evolution of mutual information shows a westward expansion of the disturbed region in the night side magnetosphere, starting from near the midnight sectors. In order to study the spatial structure in more detail the magnetic field perturbation at 39 ground stations during year 2002 and the corresponding solar wind data are compiled. The ground magnetometer data are from the two chains of stations: CANOPUS (13) and IMAGE (26). This new data set, with 1-minute resolution, is used to study the spatio-temporal structure. A technique that utilizes the daily rotation of the Earth as a longitudinal sampling process is used to construct a two dimensional representation of the high latitude magnetic perturbations both in magnetic latitude and magnetic local time. This model is used to predict the spatial structure of geomagnetic disturbances during intense geospace substorms, which are important natural hazards.
DE: 2722 Forecasting (7924, 7964)
DE: 2740 Magnetospheric configuration and dynamics
DE: 2784 Solar wind/magnetosphere interactions
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Joint Assembly