Dynamo mechanism in galaxies: nonlinear dynamics driven by cosmic rays and magnetic fields

• Project/Area Number: 23540274
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Astronomy
• Research Institution: National Astronomical Observatory of Japan
• Principal Investigator: KUDOH Takahiro 国立天文台, 理論研究部, 助教 (60413952)
• Co-Investigator(Renkei-kenkyūsha): YOKOYAMA Takaaki 東京大学, 大学院理学研究科, 准教授 (00311184) ; MATUSMOTO Ryoji 千葉大学, 大学院理学研究科, 教授 (00209660)
• Research Collaborator: KUDOH Yuki ; NASUDA Tetsuya ; MACHIDA Mami ; SUZUKI Akihiro
• Project Period (FY): 2011-04-28 – 2015-03-31
• Project Status: Completed (Fiscal Year 2014)
• Budget Amount: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000); Fiscal Year 2014: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2013: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2012: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2011: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 天文 / 宇宙物理 / 理論天文学 / 流体力学 / 流体

Outline of Final Research Achievements

The sun belongs to the Galaxy, in which there is interstellar gas between stars. In the interstellar gas, there exist magnetic fields that affect star formation, like the formation of the sun. However, it is not known how the interstellar magnetic fields are maintained. We are interested in the dynamo process that can maintain and amplify the interstellar magnetic fields, and study an important instability in that process. Especially, we focus on the effect of the high-energy particles (cosmic rays) in the interstellar space. We found that the distribution of the gas density and magnetic field dramatically alter in the interstellar space if the cosmic rays contribute to the instability, and confirmed that it will affect the dynamo process.

Research Products

• [Journal Article] Linear Growth of the Kelvin-Helmholtz Instability with an Adiabatic Cosmic-ray Gas (2014)
  • Author(s): Akihiro Suzuki, Hiroyuki R. Takahashi, Takahiro Kudoh
  • Journal Title: The Astrophysical Journal Volume: 787 Issue: 2 Pages: 169-179
  • DOI: 10.1088/0004-637x/787/2/169
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Magnetohydrodynamic Numerical Simulation of Parker Instability in Interstellar Gas with Cosmic Ray Pressure (2014)
  • Author(s): Takahiro Kudoh, Takaaki Yokoyama, Ryoji Matsumoto
  • Journal Title: Proceedings of the 12th Asia Pacific Physics Conference Volume: 1 Pages: 15015-15015
  • DOI: 10.7566/jpscp.1.015105
  • Peer Reviewed
• [Journal Article] Dynamo Activities Driven by Magnetorotational Instability and the Parker Instability in Galactic Gaseous Disks (2013)
  • Author(s): Machida, M., Nakamura, K.E., Kudoh, T., Akahori, T., Sofue, Y., Matsumoto, R
  • Journal Title: Astrophysical Journal Volume: Vol.764 Issue: 1 Pages: 81-81
  • DOI: 10.1088/0004-637x/764/1/81
  • Peer Reviewed
• [Presentation] Nonlinear Evolution of Cosmic Ray Parker Instability (2014)
  • Author(s): Takahiro Kudoh, Takaaki Yokoyama, Yuki Kudoh, Ryoji Matsumoto
  • Organizer: Plasma 2014
  • Place of Presentation: 新潟 朱鷺メッセ
  • Year and Date: 2014-11-18 – 2014-11-21
• [Presentation] 宇宙線パーカー不安定性により生じる銀河円盤の密度分布 (2014)
  • Author(s): 工藤哲洋、横山央明、工藤祐己、松元亮治
  • Organizer: 日本流体力学会年会2014
  • Place of Presentation: 東北大学 川内北キャンパス（宮城県）
  • Year and Date: 2014-09-15 – 2014-09-17
• [Presentation] 宇宙線パーカー不安定性により生じる銀河円盤の圧力と密度の鉛直分布 (2014)
  • Author(s): 工藤哲洋、横山央明、工藤祐己、松元亮治
  • Organizer: 日本天文学会2014年秋季年会
  • Place of Presentation: 山形大学 小白川キャンパス（山形県）
  • Year and Date: 2014-09-11 – 2014-09-13
• [Presentation] Numerical Simulation of Cosmic-ray Parker Instability (2014)
  • Author(s): Takahiro Kudoh, Takaaki Yokoyama, Yuki Kudoh, Ryoji Matsumoto
  • Organizer: Magnetic Reconnection 2014
  • Place of Presentation: 東京大学 山上会館（東京都）
  • Year and Date: 2014-05-20 – 2014-05-24
  • Invited
• [Presentation] 宇宙線パーカー不安定性と銀河面対称性 (2014)
  • Author(s): 工藤哲洋、工藤祐己、横山央明、松元亮治
  • Organizer: 日本地球惑星科学連合 連合大会 2014年大会
  • Place of Presentation: パシフィコ横浜 会議センター（神奈川県）
  • Year and Date: 2014-04-28 – 2014-05-02
• [Presentation] 宇宙線パーカー不安定性の赤道面対称性 (2013)
  • Author(s): 工藤哲洋、工藤祐己、横山央明、松元亮治
  • Organizer: 日本天文学会秋季年会
  • Place of Presentation: 東北大学（宮城県）
• [Presentation] 宇宙線の影響を考慮した磁気浮力不安定性のMHDシミュレーションによる２次元と３次元モデルの成長比較 (2013)
  • Author(s): 那須田哲也、横山央明、工藤哲洋
  • Organizer: 日本天文学会秋季年会
  • Place of Presentation: 東北大学（宮城県）
• [Presentation] 宇宙線の影響を受けたパーカー不安定性の数値シミュレーション (2012)
  • Author(s): 工藤哲洋、横山央明、松元亮治
  • Organizer: 日本天文学会春季年会
  • Place of Presentation: 龍谷大学（京都府）
• [Presentation] 宇宙線の影響を受けたパーカー不安定性の非線形発展 (2011)
  • Author(s): 工藤哲洋、横山央明、松元亮治
  • Organizer: 日本天文学会秋季年会
  • Place of Presentation: 鹿児島大学（鹿児島県）
• [Presentation] 宇宙線圧力の影響を受けたパーカー不安定性の磁気流体力学数値シミュレーション
  • Author(s): 工藤哲洋，横山央明，松元亮治
  • Organizer: 日本流体力学会
  • Place of Presentation: 高知大学（高知県）
• [Presentation] 宇宙線圧力の影響を受けたパーカー不安定性の数値シミュレーション
  • Author(s): 工藤哲洋，横山央明，松元亮治
  • Organizer: 日本物理学会
  • Place of Presentation: 広島大学（広島県）