HR: 0830h
AN: NG51A-0837    [PDF]
TI: Global and Multi-scale Phenomena in Geospace: Solar Wind - Magnetosphere Coupling
AU: * Sharma, A S
EM: ssh@astro.umd.edu
AF: University of Maryland, Department of Astronomy, College Park, MD 20742 United States
AU: Ukhorskiy, A Y
EM: aleksandr.ukhorskiy@jhuapl.edu
AF: Applied Physics Laboratory, Johns Hopkins Laboratory, Laurel, MD 20725 United States
AU: Sitnov, M I
EM: sitnov@glue.umd.edu
AF: University of Maryland, Institute for Research Electronics and Applied Physics, College Park, MD 20742 United States
AU: Papadopoulos, K
EM: kp@astro.umd.edu
AF: University of Maryland, Department of Astronomy, College Park, MD 20742 United States
AB: Many systems in geospace exhibit global and multiscale phenomena, characterized by processes with a wide range of spatial and temporal scales. The solar wind - magnetosphere coupling is such a system in which large scale features such as plasmoid formation, co-exists with multi-scale features such as turbulence. Although the co-existence of these features in the magnetosphere is well recognized, isolating them and understanding their relative roles have been long standing problems. To separate and model the global features of the magnetosphere a new approach for data-derived modeling based on the concept of mean-filed dimension is used. For a given level of averaging in the system the mean-field dimension determines the minimum dimension of the embedding space in which the averaged dynamical system approximates the actual dynamics with the given accuracy. It is found that the minimum embedding dimension of magnetospheric time series is a function of the level of ensemble averaging and the specified accuracy of the method. To extract the global component from the observed time series the ensemble averaging is carried out over the range of scales populated by high-dimensional multi-scale constituent. The multi-scale aspects are then described in terms of conditional probabilities computed from the solar wind and magnetospheric data. Its analysis shows that some important multi-scale properties of magnetospheric response to the solar wind activity are mainly attributed to the scale-invariance of the solar wind driver rather than to the complexity of the magnetospheric dynamics itself. These results have important implications for space weather forecasting.
DE: 2784 Solar wind/magnetosphere interactions
DE: 3220 Nonlinear dynamics
DE: 3250 Fractals and multifractals
DE: 7839 Nonlinear phenomena
DE: 7863 Turbulence
SC: Nonlinear Geophysics [NG]
MN: 2003 Fall Meeting