Generation mechanism of pulsating auroras based on their classification
| Project/Area Number |
15K05305
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | National Institute of Polar Research |
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Principal Investigator |
SATO NATSUO 国立極地研究所, その他部局等, 名誉教授 (50132709)
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| Project Period (FY) |
2015-10-21 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2016: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2015: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
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| Keywords | 脈動オーロラ / オーロラアーク / オメガバンドオーロラ / 地磁気脈動 / 磁気圏 / 電離圏 / 波動粒子相互作用 / 地上・衛星同時観測 / オーロラ脈動 / 全天カメラ / Pc5地磁気脈動 / 磁力線共鳴 / THEMIS地上観測網 / THEMIS衛星 / DMSP衛星 / オーロラ / オメガバンド / THEMIS / 極域 / 沿磁力線電場 |
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| Outline of Final Research Achievements |
Pulsating auroras with a period of a few to a few 10 seconds are common phenomena in the auroral zones. To make a breakthrough in the unsolved problems, we examined different types of pulsating auroras. We found that the quasi-periodic modulation of the DC electric field intensity and the intensity of a very low frequency (<30 Hz) electrostatic wave showed a strong correlation with the optical pulsating aurora. It is also found that Omega grows from small-scale bumps (seeds) at the poleward boundary of preexisting east-west-aligned auroras and does not exhibit any shear motion.
We also investigated the Pc5 poleward moving auroral arc pulsations (~ 4-6 min period). From the space-ground observation, it is found that the Pc5 auroral pulsations were enhanced forcibly by the magnetic and electric field variation generated by field-line resonances.
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| Academic Significance and Societal Importance of the Research Achievements |
オーロラは太陽が源で地球との相互作用で起こっている事実は解ってきた。しかし、複雑な形状や周期性を示す脈動オーロラには謎が多い。オーロラが複雑な形状を示すのは、地上と衛星との同時観測により、磁気圏と電離圏との間の相互作用によって起こっていることも解ってきた。さらに本研究により、直流電場と静電波動が脈動オーロラの強度変化に直接関与していることを観測事実から初めて明らかにできた。この成果は、磁気圏に過剰に流入した高エネルギー電子が電離圏に降り注ぐ過程の研究や、磁気圏と電離圏の相互作用の研究など、太陽と地球の関係を理解するための鍵となる事象の研究に役立つ。
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Report
(6 results)
Research Products
(33 results)
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[Journal Article] Conjugate observations of the evolution of polar cap arcs in both hemispheres2018
Author(s)
Xing, Z., Zhang, Q., Han, D., Zhang, Y., Sato, N., Zhang, S., et al.,
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Journal Title
Journal of Geophysical Research: Space Physics
Volume: 123
Issue: 3
Pages: 1-12
DOI
Related Report
Peer Reviewed / Int'l Joint Research
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[Presentation] Characteristics of electron flux variations associated with Pc5 auroral arc pulsations observed onboard THEMIS and DMSP2018
Author(s)
Sato, N., A. S. Yukimatu, Y. Tanaka, T. Hori, A. Kadokura, T. Sakurai, D. Han, Y. Ma, Q. Zhang
Organizer
The Ninth Symposium on Polar Science,
Related Report
Int'l Joint Research
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