ジオスペースにおけるトリガード・エミッションと高エネルギー粒子輸送の研究

2013 年度 研究成果報告書

• 研究課題/領域番号: 23340147
• 研究種目: 基盤研究(B)
• 配分区分: 補助金
• 応募区分: 一般
• 研究分野: 超高層物理学
• 研究機関: 京都大学
• 研究代表者: 大村 善治 京都大学, 生存圏研究所, 教授 (50177002)
• 研究分担者: 八木谷 聡 金沢大学, 理工研究領域, 教授 (30251937)
• 連携研究者: 加藤 雄人 東北大学, 理学研究科, 教授 (60378982)
• 研究期間 (年度): 2011-04-01 – 2014-03-31
• キーワード: プラズマ波動 / 計算機シミュレーション / 放射線帯 / 相対論的電子 / 非線形波動 / 非線形ダイナミックス / 不安定性 / 内部磁気圏

研究概要

ホイッスラーモード波・コーラス放射および電磁イオンサイクロトロン（ＥＭＩＣ）波トリガード放射の発生機構について、衛星観測に基づいて物理モデルを作り、第一原理に基づく計算機シミュレーションを実行し、エミッションの再現することに成功した。さらに、その理論解析を通じて、内在する非線形波動粒子相互作用の素過程を解明することができた。特に、これまでの研究では、わかっていなかった周波数上昇を伴う非線形成長の飽和過程とサブパケット構造を持つコーラス放射の形成機構に関する理解において大きな進展があった。

研究成果

• [雑誌論文] Nonlinear damping of chorus emissions at local half cyclotron frequencies observed by Geotail at L > 9 (2014)
  • 著者名/発表者名: T. Habagishi, S. Yagitani, and Y. Omura
  • 雑誌名: J. Geophys. Res.
  • DOI: 10.1002/2013JA019696
• [雑誌論文] Geotail observation of upper-band and lower-band chorus elements in the outer magnetosphere (2014)
  • 著者名/発表者名: S. Yagitani, T. Habagishi, and Y. Omura
  • 雑誌名: J. Geophys. Res.
  • DOI: 10.1002/2013JA019678
• [雑誌論文] Spectrum characteristics of electromagnetic ion cyclotron triggered emissions and associated energetic proton dynamics (2014)
  • 著者名/発表者名: M. Shoji and Y. Omura
  • 雑誌名: J. Geophys. Res. 巻: 119
  • DOI: 10.1002/2013JA019695
• [雑誌論文] Direct Measurement of Nonlinear Wave-Particle Interactions in the Earth's Magnetosphere, Wave-Particle Interaction Analyzer (WPIA) for ERG Mission (2014)
  • 著者名/発表者名: Y. Katoh, M. Hikishima, H. Kojima, Y. Omura, S. Kasahara, M. Hirahara, Y. Miyoshi, K. Seki, K. Asamura, T. Takeshima, T. Ono
  • 雑誌名: JPS Conf. Proc. 巻: 015100
• [雑誌論文] Electromagnetic ion cyclotron rising tone emissions observed by THEMIS probes outside the plasmapause (2014)
  • 著者名/発表者名: S. Nakamura, Y. Omura, S. Machida, M. Shoji, M, Nose, V. Angelopoulos
  • 雑誌名: J. Geophys. Res. 巻: 119
  • DOI: 10.1002/2013JA019146
• [雑誌論文] Akebono observations of EMIC waves in the slot region of the radiation belts (2013)
  • 著者名/発表者名: K. Sakaguchi, Y. Kasahara, M. Shoji, Y. Omura, Y. Miyoshi, T. Nagatsuma, A. Kumamoto and A. Matsuoka
  • 雑誌名: Geophys. Res. Lett. 巻: 40
  • DOI: 10.1002/2013GL058258
• [雑誌論文] Electron acceleration by Z-mode and whistler-mode waves (2013)
  • 著者名/発表者名: K. H. Lee, Y. Omura, and L. C. Lee
  • 雑誌名: Phys. Plasmas 巻: 20 ページ: 112901
  • DOI: 10.1063/1.4829439
• [雑誌論文] Triggering process of electromagnetic ion cyclotron rising tone emissions in the inner magnetosphere (2013)
  • 著者名/発表者名: M. Shoji and Y. Omura
  • 雑誌名: J. Geophys. Res. 巻: 118 ページ: 5553-5561
  • DOI: 10.1002/jgra.50523
• [雑誌論文] Relativistic electron microbursts due to nonlinear pitch-angle scattering by EMIC triggered emissions (2013)
  • 著者名/発表者名: Y. Omura and Q. Zhao
  • 雑誌名: J. Geophys. Res.
  • DOI: 10.1002/jgra.50477
• [雑誌論文] Parameter spaces for linear and nonlinear whistler-mode waves (2013)
  • 著者名/発表者名: D. Summers, R. Tang, Y. Omura, and D. H. Lee
  • 雑誌名: Phys. Plasmas 巻: 20 ページ: 072110
  • DOI: 10.1063/1.4816022
• [雑誌論文] Effect of the background magnetic field inhomogeneity on generation processes of whistler-mode chorus and broadband hiss-like emissions (2013)
  • 著者名/発表者名: Y. Katoh and Y. Omura
  • 雑誌名: J. Geophys. Res.
  • DOI: 10.1002/jgra.50395
• [雑誌論文] Ray tracing of whistler-mode chorus elements : implications for generation mechanisms of rising and falling tone emissions (2013)
  • 著者名/発表者名: K. Yamaguchi, T. Matsumuro, Y. Omura, and D. Nunn
  • 雑誌名: Ann. Geophys. 巻: 31 ページ: 665-673
• [雑誌論文] Significance of Wave-Particle Interaction Analyzer for direct measurements of nonlinear wave-particle interactions (2013)
  • 著者名/発表者名: Y. Katoh, M. Kitahara, H. Kojima, Y. Omura, S. Kasahara, M. Hirahara, Y. Miyoshi, K. Seki, K. Asamura, T. Takashima, and T. Ono
  • 雑誌名: Ann. Geophys. 巻: 31 ページ: 503-512
• [雑誌論文] EMIC triggered chorus emissions in Cluster data (2013)
  • 著者名/発表者名: Grison, B., O. Santolik, N. Cornilleau-Wehrlin, A. Masson, M. J. Engebretson, J. S. Pickett, Y. Omura, P. Robert, R. Nomura
  • 雑誌名: J. Geophys. Res. 巻: 118
  • DOI: 10.1002/jgra.50178
• [雑誌論文] The Energization and Radiation in Geospace (ERG) Project, AGU Monograph "Dynamics of the Earth's Radiation Belts and Inner Magnetosphere" (2012)
  • 著者名/発表者名: Y. Miyoshi, T. Ono, T. Takashima, K. Asamura, M. Hirahara, Y. Kasaba, A. Matsuoka, H. Kojima, K. Shiokawa, K. Seki, M. Fujimoto, T. Nagatsuma, C.Z. Cheng, Y. Kazama, S. Kasahara, T. Mitani, H. Matsumoto, N. Higashio, A. Kumamoto, Yagitani, Y. Kasahara, K. Ishisaka, L. Blomberg, A. Fujimoto, Y. Katoh, Y. Ebihara, Y. Omura, M. Nosé, T. Hori, Y. Miyashita, Y.-M. Tanaka and T. T. Segawa
  • 雑誌名: The Energization and Radiation in Geospace (ERG) Project
  • DOI: 10.1029/2012GM001304
• [雑誌論文] Linear and Nonlinear Growth of Magnetospheric Whistler Mode Waves (2012)
  • 著者名/発表者名: D. Summers, R. Tang, and Y. Omura
  • 雑誌名: AGU Monograph "Dynamics of the Earth's Radiation Belts and Inner Magnetosphere"
  • DOI: 10.1029/2012GM001298
• [雑誌論文] Generation processes of whistler-mode chorus emissions : Current status of nonlinear wave growth theory (2012)
  • 著者名/発表者名: Omura Y., D. Nunn, and D. Summers
  • 雑誌名: AGU Monograph "Dynamics of the Earth's Radiation Belts and Inner Magnetosphere"
  • DOI: 10.1029/2012GM001347
• [雑誌論文] THEMIS observation of chorus elements without a gap at half the gyrofrequency (2012)
  • 著者名/発表者名: S. Kurita, Y. Katoh, Y. Omura, V. Angelopoulos, C. M. Cully, O. Le Contel,and H. Misawa
  • 雑誌名: J. Geophys. Res. 巻: VOL.117 ページ: A11223
  • DOI: 10.1029/2012JA018076
• [雑誌論文] Precipitation of highly energetic protons by helium branch electromagnetic ion cyclotron triggered emissions (2012)
  • 著者名/発表者名: Shoji, M., and Y. Omura
  • 雑誌名: J. Geophys. Res. 巻: VOL.117 ページ: A12210
  • DOI: 10.1029/2012JA017933
• [雑誌論文] Nonlinear spatio-temporal evolution of whistler mode chorus waves in Earth's inner magnetosphere (2012)
  • 著者名/発表者名: Summers, D., Y. Omura, Y. Miyashita, and D.-H. Lee
  • 雑誌名: J. Geophys. Res. 巻: 117 ページ: A09206
  • DOI: 10.1029/2012JA017842
• [雑誌論文] A computational and theoretical analysis of falling frequency VLF emissions (2012)
  • 著者名/発表者名: Nunn, D., and Y. Omura
  • 雑誌名: J. Geophys. Res. 巻: 117 ページ: A08228
  • DOI: 10.1029/2012JA017557
• [雑誌論文] Nonlinear pitch-angle scattering of relativistic electrons by EMIC waves in the inner magnetosphere (2012)
  • 著者名/発表者名: Omura Y., and Q. Zhao
  • 雑誌名: J. Geophys. Res. 巻: 117 ページ: A08227
  • DOI: 10.1029/2012JA017943
• [雑誌論文] Multidimensional nonlinear mirror-mode structures in the Earth's magnetosheath (2012)
  • 著者名/発表者名: Shoji, M., Y. Omura, and L.-C. Lee
  • 雑誌名: J. Geophys. Res. 巻: 117
  • DOI: 10.1029/2011JA017420
• [雑誌論文] Particle simulations of whistler-mode rising-tone emissions triggered by waves with different amplitudes (2012)
  • 著者名/発表者名: Hikishima, M., and Y. Omura
  • 雑誌名: J. Geophys. Res. 巻: 117 ページ: A04226
  • DOI: 10.1029/2011JA017428
• [雑誌論文] Effects of nonlinear wave growth on extreme radiation belt electron fluxes (2011)
  • 著者名/発表者名: Summers, D., R. Tang, and Y. Omura
  • 雑誌名: J. Geophys. Res. 巻: 116 ページ: A10226
  • DOI: 10.1029/2011JA016602
• [雑誌論文] Electromagnetic ion cyclotron waves in the helium branch induced by multiple electromagnetic ion cyclotron triggered emissions (2011)
  • 著者名/発表者名: Shoji, M., Y. Omura, B. Grison, J. Pickett, I. Dandouras, and M. Engebretson
  • 雑誌名: Geophys. Res. Lett. 巻: 38 ページ: L17102
  • DOI: 10.1029/2011GL048427
• [雑誌論文] Amplitude dependence of frequency sweep rates of whistler mode chorus emissions (2011)
  • 著者名/発表者名: Katoh, Y., and Y. Omura
  • 雑誌名: J. Geophys. Res. 巻: 116 ページ: A07201
  • DOI: 10.1029/2011JA016496
• [雑誌論文] Simulation of electromagnetic ion cyclotron triggered emissions in the Earth's inner magnetosphere (2011)
  • 著者名/発表者名: Shoji, M., and Y. Omura
  • 雑誌名: J. Geophys. Res. 巻: 116 ページ: A05212
  • DOI: 10.1029/2010JA016351
• [雑誌論文] Triggering process of whistler mode chorus emissions in the magnetosphere (2011)
  • 著者名/発表者名: Omura, Y., and D. Nunn
  • 雑誌名: J. Geophys. Res. 巻: 116 ページ: A05205
  • DOI: 10.1029/2010JA016280
• [学会発表] Generatin mechanism of whistler-mode chorus emissions (2014)
  • 著者名/発表者名: Y. Omura
  • 学会等名: VERSIM 2014
  • 発表場所: Dunedin, New Zealand
  • 年月日: 2014-01-20
  • 招待講演
• [学会発表] Generation of EMIC triggered emissions and associated precipitations of energetic protons and relativistic electrons in the Earth's inner magnetosphere (2013)
  • 著者名/発表者名: Y. Omura
  • 学会等名: Naval Research Laboratory, Plasma Physics Devision Colloquium
  • 発表場所: Washington DC, USA
  • 年月日: 2013-12-17
  • 招待講演
• [学会発表] Nonlinear processes of whistler-mode wave-particle interactions (2012)
  • 著者名/発表者名: Y. Omura
  • 学会等名: BSP SWG Meeting
  • 発表場所: APL, U.S.A
  • 年月日: 20120516-17
  • 招待講演
• [学会発表] Generation mechanism of whistler-mode chorus emissions (2012)
  • 著者名/発表者名: Y. Omura
  • 学会等名: 39th COSPAR
  • 発表場所: Mysore, India
  • 年月日: 2012-07-19
  • 招待講演
• [学会発表] NONLINEAR MIRROR MODE STRUCTURES IN MULTIDIMENSIONAL MODELS (2011)
  • 著者名/発表者名: M. Shoji, Y. Omura, L.-C. Lee
  • 学会等名: URSI XXX General Assembly Istanbul
  • 発表場所: Turky
  • 年月日: 20110811-15
  • 招待講演
• [学会発表] Particle Simulations of Whistler-mode Chorus and Electromagnetic Ion Cyclotron Waves (2011)
  • 著者名/発表者名: Y. Omura
  • 学会等名: 10th International School for Space Simulations (ISSS-10)
  • 発表場所: Banff, Canada
  • 年月日: 20110725-30
  • 招待講演
• [学会発表] Formation process of relativistic electron flux through interaction with chorus emissions in the Earth's inner magnetosphere (2011)
  • 著者名/発表者名: Y. Omura
  • 学会等名: AGU Chapman Conference on Dynamics of the Earth's Radiation Belts and Inner Magnetosphere
  • 発表場所: St. John's, Newfoundland and Labrador, Canada
  • 年月日: 20110717-22
  • 招待講演
• [図書] Generation processes of whistler-mode chorus emissions: Current status of nonlinear wave growth theory, AGU Monograph "Dynamics of the Earth's Radiation Belts and Inner Magnetosphere" (2012)
  • 著者名/発表者名: Omura Y., D. Nunn, and D. Summers
• [図書] Linear and Nonlinear Growth of Magnetospheric Whistler Mode Waves, AGU Monograph "Dynamics of the Earth's Radiation Belts and Inner Magnetosphere" (2012)
  • 著者名/発表者名: D. Summers, R. Tang, and Y. Omura
• [図書] The Energization and Radiation in Geospace (ERG) Project, AGU Monograph "Dynamics of the Earth's Radiation Belts and Inner Magnetosphere", The Energization and Radiation in Geospace (ERG) Project (2012)
  • 著者名/発表者名: Y. Miyoshi, T. Ono, T. Takashima, K. Asamura, M. Hirahara, Y. Kasaba, A. Matsuoka, H. Kojima, K. Shiokawa, K. Seki, M. Fujimoto, T. Nagatsuma, C.Z. Cheng, Y. Kazama, S. Kasahara, T. Mitani, H. Matsumoto, N. Higashio, A. Kumamoto, S. Yagitani, Y. Kasahara, K. Ishisaka, L. Blomberg, A. Fujimoto, Y. Katoh, Y. Ebihara, Y. Omura, M. Nosé, T. Hori, Y. Miyashita, Y.-M. Tanaka and T. T. Segawa