Imaging of polar cap ionosphere with three all-sky airglow imagers

2019 Fiscal Year Final Research Report

• Project/Area Number: 26302006
• 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: The University of Electro-Communications
• Principal Investigator: Hosokawa Keisuke 電気通信大学, 大学院情報理工学研究科, 教授 (80361830)
• Co-Investigator(Kenkyū-buntansha): 田口 聡 京都大学, 理学研究科, 教授 (80251718)
• Project Period (FY): 2014-04-01 – 2020-03-31
• Keywords: 電離圏 / 夜間大気光 / 北極域 / ポーラーキャップパッチ

Outline of Final Research Achievements

We have constructed a network of ground-based airglow measurements by installing a new airglow imager in Eureka, Canada. This network observation enables us to visualize the electron density variations at the polar cap latitudes, for example, those produced by polar cap patches. By using airglow data from this network we have shown 1) that the spatial structure of polar cap patches is characterized through plasma instability such as gradient-drift instability, 2) that some patches are generated directly from the transient poleward moving aurora in the dayside cusp, 3) that UT and seasonal variations of polar cap patch occurrence are determined by the offset between the geographic and geomagnetic poles, and 4) cheap and small airglow imager is able to detect weak airglow enhancement during the passage of polar cap patches.

Free Research Field

超高層大気物理学

Academic Significance and Societal Importance of the Research Achievements

緯度が 80 度を超える極冠域の電離圏に見られる擾乱現象の一つである「ポーラーキャップパッチ」の空間構造や時間変動を決定している要因を明らかした．これは，電離圏密度の乱れが衛星測位システムに与える影響を評価するための基盤情報として活用することができる．また，ポーラーキャップパッチの発生頻度の日変化や季節変化も統計的に明らかにした．この情報を用いることで，ポーラーキャップパッチの発生が測位に与える影響を予測することが可能になっている．