HR: 11:50h
AN: SM22A-07    [Abstracts]
TI: AKR Activity During Magnetically Quiet Periods
AU: * Morioka, A
EM: morioka@pparc.geophys.tohoku.ac.jp
AF: Planetary Plasma and Atmospheric research Center, Tohoku University, Aoba, Aramaki, Aobaku-ku, Sendai, 980-8578 Japan
AU: Miyoshi, Y
EM: miyoshi@stelab.nagoya-u.ac.jp
AF: Solar-Terrestrial Environment Laboratory, Nagoya University, 3-13, Honohara, Toyokawa, 442-8507 Japan
AU: Misawa, H
EM: misawa@pparc.geophys.tohoku.ac.jp
AF: Planetary Plasma and Atmospheric research Center, Tohoku University, Aoba, Aramaki, Aobaku-ku, Sendai, 980-8578 Japan
AU: Tsuchiya, F
EM: tsuchiya@pparc.geophys.tohoku.ac.jp
AF: Planetary Plasma and Atmospheric research Center, Tohoku University, Aoba, Aramaki, Aobaku-ku, Sendai, 980-8578 Japan
AU: Sakanoi, T
EM: tsakanoi@pparc.geophys.tohoku.ac.jp
AF: Planetary Plasma and Atmospheric research Center, Tohoku University, Aoba, Aramaki, Aobaku-ku, Sendai, 980-8578 Japan
AU: Oya, H
EM: oya@ccmails.fukui-ut.ac.jp
AF: Fukui University of Technology, 3-6-1, Gakuen, Fukui, 910-8505 Japan
AU: Matsumoto, H
EM: matsumot@rish.kyouto-u.ac.jp
AF: Research Institute for Sustainable Humanosphere, Kyoto University, Gokasyo, Uji, 611-0011 Japan
AU: Hashimoto, K
EM: kozo@rish.kyoto-u.ac.jp
AF: Research Institute for Sustainable Humanosphere, Kyoto University, Gokasyo, Uji, 611-0011 Japan
AU: Mukai, T
EM: mukai@stp.isas.jaxa.jp
AF: ISAS, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Sagamihara, 229-8510 Japan
AB: Auroral kilometric radiation (AKR) intensity is well known to be closely related to the substorm activity, indicating that the substorm strength controls the AKR development. In this study, we present the activity of AKR during magnetically quiet periods, when AE index is less than 100 nT, auroral oval is contracted to higher latitude, and particle injection is not detected at the geosynchronous orbit. The investigation showed that the onset of the "quiet time AKR" is triggered by a small substorm in the magnetosphere which is manifested by the small but clear auroral break-up, Pi2 pulsation, and sudden plasma flow in the plasma sheet. It is also shown that the quiet time AKR sometimes appears with an intense amplitude comparable with the usual substorm-time AKR. These results suggest that AKR appearance is related to the onset of substorm but development of AKR does not always depend on the scale of substorm.
DE: 2704 Auroral phenomena (2407)
DE: 2716 Energetic particles, precipitating
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2772 Plasma waves and instabilities
DE: 2788 Storms and substorms
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting