HR: 1340h
AN: SM53A-0398    [Abstracts]
TI: Estimation of global distribution of large-scale field-aligned currents on the basis of ground-based magnetic data at mid-latitudes and in the polar-cap
AU: * Nakano, S
EM: shiny@kugi.kyoto-u.ac.jp
AF: Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-Cho, Sakyo-ku, Kyoto, 606-8502 Japan
AU: Iyemori, T
EM: iyemori@kugi.kyoto-u.ac.jp
AF: Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-Cho, Sakyo-ku, Kyoto, 606-8502 Japan
AB: East-west geomagnetic disturbances at middle latitudes are mainly attributed to variations of field-aligned currents. In the dark region of the polar cap where ionospheric conductivity is small and effects of ionospheric currents are negligible, geomagnetic disturbances are mainly attributed to variations of field-aligned currents as well. Therefore significant information concerning field-aligned currents can be obtained from geomagnetic data at middle latitudes and those in the polar cap. In this study, we tried to estimate global distribution of large-scale field-aligned currents from a combination of middle latitude and polar-cap geomagnetic data with a simple inversion method. The results are generally consistent with past statistical studies based on spacecraft observations on an average. In addition, this inversion method enables us to stably infer temporal variations of global distribution of field-aligned currents, which can not be obtained from spacecraft observations. Then, we will discuss characteristics of variations in the distribution of field-aligned currents during geomagnetically disturbed conditions.
DE: 2409 Current systems (2708)
DE: 2708 Current systems (2409)
DE: 2788 Storms and substorms
DE: 2794 Instruments and techniques
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting