HR: 1340h
AN: SM23A-0474    [Abstracts]
TI: Akebono satellite observations of Alfv\'{e}n waves related to dayside small-scale field-aligned currents
AU: * Hasunuma, T
EM: hasunuma@pat.geophys.tohoku.ac.jp
AF: Department of Geophysics, Graduate School of Science, Tohoku University, Aramaki-aoba, Aoba, Sendai, Miyagi 980-8578, Japan, Sendai, 980-8578 Japan
AU: Fukunishi, H
EM: fuku@pat.geophys.tohoku.ac.jp
AF: Department of Geophysics, Graduate School of Science, Tohoku University, Aramaki-aoba, Aoba, Sendai, Miyagi 980-8578, Japan, Sendai, 980-8578 Japan
AU: Nagatsuma, T
EM: tnagatsu@nict.go.jp
AF: National Institute of Information and Communications Technology, 4-2-1 Nukui-kita, Koganei, Tokyo 184-8795, Japan, Koganei, 184-8795 Japan
AU: Kataoka, R
EM: ryuho@nict.go.jp
AF: National Institute of Information and Communications Technology, 4-2-1 Nukui-kita, Koganei, Tokyo 184-8795, Japan, Koganei, 184-8795 Japan
AU: Takahashi, Y
EM: yukihiro@pat.geophys.tohoku.ac.jp
AF: Department of Geophysics, Graduate School of Science, Tohoku University, Aramaki-aoba, Aoba, Sendai, Miyagi 980-8578, Japan, Sendai, 980-8578 Japan
AU: Matsuoka, A
EM: matsuoka@stp.isas.jaxa.jp
AF: Japan Aerospace Exploration Agency/Institute of Space and Astronautical Science, 3-1-1 Yoshinodai,Sagamihara, Kanagawa 229-8510, Japan, Sagamihara, 229-8510 Japan
AU: Kumamoto, A
EM: kumamoto@stpp1.geophys.tohoku.ac.jp
AF: Department of Geophysics, Graduate School of Science, Tohoku University, Aramaki-aoba, Aoba, Sendai, Miyagi 980-8578, Japan, Sendai, 980-8578 Japan
AB: In the cusp and its surrounding region, burst-like disturbances of magnetic and electric fields are often observed on Freja, FAST, Akebono, and Cluster spacecraft. Recent studies suggest that these small-scale disturbances are signatures of the dispersive Alfv\'{e}n wave (DAW) and the ionospheric Alfv\'{e}n resonator (IAR) excited in the magnetosphere-ionosphere coupled system [{\itHirano et al.}, 2004]. These small-scale disturbances would also carry small-scale field-aligned currents (FACs). In our recent study, we investigated statistically the polar distributions of small-scale FACs and showed that small-scale FACs are enhanced in the vicinity of the cusp, particularly in the prenoon Region 1 current system. These dayside small-scale FACs are enhanced on sunlit conditions, suggesting that small-scale FACs are significantly affected by ionospheric conductivity. The purpose of this study is to elucidate the characteristics of Alfv\'{e}n waves related to small-scale FACs using Akebono magnetic and electric field data. Comparing with the in-situ electron density data, the role of DAW and IAR on the generation of small-scale FACs are discussed, focusing particularly on the altitude dependence.
UR: http://pat.geophys.tohoku.ac.jp
DE: 2483 Wave/particle interactions
DE: 2708 Current systems (2409)
DE: 2724 Magnetopause, cusp, and boundary layers
DE: 2736 Magnetosphere/ionosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting