Japan Geoscience Union Meeting 2018

Presentation information

[EE] Oral

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

[P-EM16] Dynamics of Earth's Inner Magnetosphere and Initial Results from Arase

Tue. May 22, 2018 10:45 AM - 12:15 PM 303 (3F International Conference Hall, Makuhari Messe)

convener:Danny Summers(Memorial University of Newfoundland), Yoshizumi Miyoshi(Institute for Space-Earth Environmental Research, Nagoya University), Keisuke Hosokawa(電気通信大学大学院情報理工学研究科, 共同), Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University), Chairperson:Hosokawa Keisuke(The University of Electro-Communications)

11:30 AM - 11:45 AM

[PEM16-28] Spatial distribution of radiation belt protons deduced from solar cell degradation of the Arase satellite

*Honoka Toda1, Wataru Miyake1, Yoshizumi Miyoshi2, Hiroyuki Toyota3, Yu Miyazawa3, Iku Shinohara3, Ayako Matsuoka3 (1.Tokai University, 2.ISEE, Nagoya Universiyu, 3.ISAS/JAXA)

Keywords:The Arase satellite, Proton radiation belt, Solar cell degradation

Solar cells mounted on any satellites are susceptible to effect of abundant space radiations. Solar cells on the Arase satellite orbiting in the inner magnetosphere degrade due to trapped protons with energies of more than 6 MeV. In the current study, we try to deduce spatial distribution of the radiation belt protons from analysis of output variation of the SAP (Solar-cell Array Panel) of the Arase satellite.

Analysis of the SAP data from launch (20 December, 2016) to 2017 year-end showed a clear degradation that could be attributed to trapped protons. Radiation dosage was determined from Voc (Open circuit voltage) variation of the solar cells and we made comparison with those expected from various distribution models (AP8MAX, AP9MEAN and CRRESPRO quiet) of trapped protons. We found a general agreement with degradation expected from the distribution models, which demonstrates that the trapped protons are major cause of the degradation. However, there remains a little difference in expected radiation dosage from the model calculations. The Voc is also sensitive to temperature. We modify the models, including temperature variation, to minimize the difference and discuss the spatial distribution of trapped MeV protons.