Elucidation of auroral polarization by spectral polarization imaging observation

2017 Fiscal Year Final Research Report

• Project/Area Number: 26302005
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 海外学術
• Research Field: Space and upper atmospheric physics
• Research Institution: Tohoku University
• Principal Investigator: Sakanoi Takeshi 東北大学, 理学研究科, 准教授 (80271857)
• Co-Investigator(Kenkyū-buntansha): 鍵谷 将人 東北大学, 理学研究科, 助教 (30436076)
• Co-Investigator(Renkei-kenkyūsha): SHIOKAWA Kazuo 名古屋大学, 太陽地球環境研究所, 教授 (80226092) ; OYAMA Shin-ichiro 名古屋大学, 太陽地球環境研究所, 講師 (20444424)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: オーロラ / 偏光 / 電離圏 / 磁気圏 / 装置開発

Outline of Final Research Achievements

We aim to reveal the elevation distribution of auroral polarization along the magnetic meridian by using a newly developed wide field auroral polarization imaging spectrometer. IWe also developed a calibration light system to validate apparent polarization caused by atmospheric scattering and instrument. We installed the instrument at Pokar Flat Research Range, Alaska in November of 2015 and took many calibration data for various field-of-views. Using the calibration data, we evaluated polarization degree with an accuracy better than 0.2 percent. We obtained the linear polarization degree of 630 nm aurora as 1.6 +/- 0.9 percent. For most cases, polarization degree showed a tendency that maximized at the low elevation angle, and decreases as the elevation angle increases. In addition, we contributed the international collaboration with Norway by coordinated EISCAT-radar and optical observations. 4 master students and 2 undergraduate students were graduated based on this study.

Free Research Field

惑星電離園磁気圏物理学