HR: 1340h
AN: SM33B-0453    [Abstracts]
TI: Empirical Modeling of the Geomagnetic Field: A High-resolution Tail Current Sheet Module
AU: Tsyganenko, N A
SM33B-0453 AF: Universities Space Research Association and Laboratory for Solar and Space Physics, NASA Goddard Space Flight Center, Code 612.3, Greenbelt, MD 20771 United States
AU: * Sitnov, M I
EM: sitnov@umd.edu
AF: Institute for Research in Electronics and Applied Physics, University of Maryland, Energy Research Facility (Bldg. #223), Paint Branch Drive, University of Maryland, College Park, MD 20742-3511 United States
AU: Ukhorskiy, A Y
EM: aleksandr.ukhorskiy@jhuapl.edu
AF: Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723-6099 United States
AB: Present empirical models are inherently limited in resolving both the spatial structure of the geomagnetic field and its dynamics. In particular, in the recent models [Tsyganenko, 1996, 2002] the tail current sheet system includes only two basic modules, describing the near-Earth and mid-tail dynamics. To accurately model and forecast energetic particle fluxes in the near magnetosphere during storms and substorms, we are pursuing a new approach, aimed at the development of a new generation of empirical models. These models (A) will explicitly take into account different loading and relaxation time scales of magnetospheric current systems and (B) will be free of limitations due to the use of a limited set of localized basis functions for each of the principal current systems. As a first result of this project, a multi-scale empirical model was recently released [Tsyganenko and Sitnov, 2005], in which each principal magnetospheric current system had its own relaxation timescale. Here we report on the next step in this program, namely a new empirical model, in which the tail field is expanded into a series of basic functions, corresponding to fields of current disks with an arbitrary distribution of the current in the equatorial plane, including the longitudinally asymmetric terms. Each of the basis fields in the spectral expansion is confined within a model magnetopause, using appropriate sets of potential shielding fields. Some results of the reconstruction of the tail field and the dynamics of the cross-tail current in the new model will be presented.
DE: 2409 Current systems (2721)
DE: 2722 Forecasting (7924, 7964)
DE: 2740 Magnetospheric configuration and dynamics
DE: 2744 Magnetotail
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005