Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 26, 1335-1339, 2008
https://doi.org/10.5194/angeo-26-1335-2008
© Author(s) 2008. This work is distributed under
the Creative Commons Attribution 3.0 License.
 
11 Jun 2008
Average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit
R. Kataoka1 and Y. Miyoshi2 1RIKEN (The Institute of Physics and Chemical Research) 2-1, Hirosawa, Wako, 351-0198, Japan
2Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Nagoya, Aichi, 464-8601, Japan
Abstract. We report average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit (GEO). It is found that seven of top ten extreme events at GEO during solar cycle 23 are associated with the magnetosphere inflation during the storm recovery phase as caused by the large-scale solar wind structure of very low dynamic pressure (<1.0 nPa) during rapid speed decrease from very high (>650 km/s) to typical (400–500 km/s) in a few days. For the seven events, the solar wind parameters, geomagnetic activity indices, and relativistic electron flux and geomagnetic field at GEO are superposed at the local noon period of GOES satellites to investigate the physical cause. The average profiles support the "double inflation" mechanism that the rarefaction of the solar wind and subsequent magnetosphere inflation are one of the best conditions to produce the extreme flux enhancement at GEO because of the excellent magnetic confinement of relativistic electrons by reducing the drift loss of trapped electrons at dayside magnetopause.

Citation: Kataoka, R. and Miyoshi, Y.: Average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit, Ann. Geophys., 26, 1335-1339, https://doi.org/10.5194/angeo-26-1335-2008, 2008.
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