Japan Geoscience Union Meeting 2014

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International Session (Oral)

Symbol P (Space and Planetary Sciences) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM08_2PM1] Space Weather and Space Climate

Fri. May 2, 2014 2:15 PM - 4:00 PM 411 (4F)

Convener:*Ryuho Kataoka(National Institute of Polar Research), Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University), Kanya Kusano(Solar-Terrestrial Environment Laboratory, Nagoya University), Toshifumi Shimizu(Institute of Space and Astronautical Science, JAXA), Yoshizumi Miyoshi(Solar-Terrestrial Environement Laboratory, Nagoya University), Ayumi Asai(Unit for Synergetic Studies of Space, Kyoto University), Tatsuhiko Sato(Japan Atomic Energy Agency), Hidekatsu Jin(National Institude of Information and Communications Technology), Kiminori Itoh(Graduate School of Engineering, Yokohama National University), Hiroko Miyahara(College of Art and Design, Musashino Art University), Chair:Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University), Yoshizumi Miyoshi(Solar-Terrestrial Environement Laboratory, Nagoya University)

2:45 PM - 3:00 PM

[PEM08-23] Dynamical estimation of external/internal acceleration processes of the outer radiation belt using data assimilation

*Yoshizumi MIYOSHI1, Haruto TOYAMA1, Genta UENO2, Hideki KOSHIISHI3, Haruhisa MATSUMOTO3, Kazuo SHIOKAWA1 (1.STEL, Nagoya University, 2.The Institute of Statistical Mathematics, 3.JAXA)

Keywords:radiation belts, data assimilation

Dynamical evolution of the outer belts should be a delicate balance among several processes. It has been believed that there exist two different acceleration mechanisms: the radial diffusion as the external source process, and the non-adiabatic wave particle interactions as the internal source process. In order to discriminate when and where these processes are dominant for the large flux enhancement of the outer belt electrons, we have developed a data assimilation code on the outer belt electrons. In our data assimilation, the particle filter and the particle smoother are used which are effective for non-linear/non-Gaussian distribution problems. We include the radial diffusion coefficient and the internal source model in the state vector and estimate the dynamical variations of these parameters. The Tsubasa satellite electron data are used as the observation vector. The results indicate that only the radial diffusion process is always too small to explain the observed flux enhancement and the internal source process should be necessary. The assimilation result suggests that the internal source process tend to take place around the storm recovery phase, which is consistent with the observations.