Study on dynamic behavior of recombination front and its control in detached plasma

• Project/Area Number: 19K14686
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 14020:Nuclear fusion-related
• Research Institution: National Institute for Fusion Science
• Principal Investigator: HAYASHI Yuki 核融合科学研究所, ヘリカル研究部, 助教 (00823387)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2022: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2021: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2020: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
• Keywords: 非接触プラズマ / 再結合フロント / 熱パルス / 直線型装置 / リサイクリング / 流体コード / 体積再結合

Outline of Research at the Start

核融合炉のダイバータ領域における非接触プラズマ中の再結合フロント領域は、プラズマの熱流制御と粒子制御の両面から重要な役割を担う。再結合フロントを定常維持し、その位置を適切に制御する必要がある。本研究は外部制御が容易な磁場配位の制御によりプラズマ-中性粒子相互作用の実効的断面積を局所的に変化させ、再結合フロントの磁力線方向位置を制御する新たな手法の実証を行う。さらに、炉心プラズマから流出した間欠的熱負荷が再結合フロントに流入した際の再結合フロントの動的挙動(崩壊・回復の時定数や電位構造の動的変化)を明らかにする。

Outline of Final Research Achievements

The interaction between a detached plasma, which is considered to be a promising method to reduce the heat load into the plasma facing wall in a fusion reactor, and a transient pulsed plasma due to instabilities has been studied through experiments using the linear plasma device Magnum-PSI and the modeling using 2D plasma fluid simulation. It was concluded that last-part of the pulsed plama was suppressed by the enhancement of the recycled neutral particle flux generated at the target because the first half of the pulse was observed as the target current.

Academic Significance and Societal Importance of the Research Achievements

熱核融合発電の実現に向けて、炉心からの過渡的な熱粒子放出現象に伴う炉壁への熱負荷を低減することが必須である。本研究では、パルスプラズマ自身が発生させるリサイクリング粒子束が後続のパルスを減衰させる現象を見出した。この現象を利用・発展させることで、非接触プラズマを用いた過渡的熱負荷の緩和手法を確立させ、熱核融合発電の早期実現に貢献できると考えられる。

Research Products

• [Int'l Joint Research] DIFFER(オランダ)
• [Int'l Joint Research] DIFFER(オランダ)
• [Int'l Joint Research] DIFFER(オランダ)
• [Int'l Joint Research] DIFFER(オランダ)
• [Journal Article] Effects from the Target Plate Geometry on Fluctuations of Helium Plasma in the Linear Divertor Simulator Magnum-PSI (2022)
  • Author(s): YOSHIKAWA Masayuki、TANAKA Hirohiko、HAYASHI Yuki、KAJITA Shin、van der MEIDEN Hennie、VERNIMMEN Jordy、MORGAN Thomas、KOHAGURA Junko、SHIMA Yoriko、TOGO Satoshi、EZUMI Naomichi、NAKASHIMA Yousuke、SAKAMOTO Mizuki
  • Journal Title: Plasma and Fusion Research Volume: 17 Issue: 0 Pages: 1402100-1402100
  • DOI: 10.1585/pfr.17.1402100
  • ISSN: 1880-6821
  • Year and Date: 2022-10-07
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Reduction of pulsed particle load with dynamic pressure induced by transient recycled neutral flux (2022)
  • Author(s): Hayashi Yuki、Tanaka Hirohiko、Ohno Noriyasu、Kajita Shin、Morgan Thomas、van der Meiden Hennie、Scholten John、Vernimmen Jordy、Natsume Hiroki、Sawada Keiji、Masuda Shota
  • Journal Title: Plasma Physics and Controlled Fusion Volume: 64 Issue: 10 Pages: 105013-105013
  • DOI: 10.1088/1361-6587/ac8acb
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Accelerated/reduced growth of tungsten fuzz by deposition of metals (2021)
  • Author(s): Kajita Shin、Morgan Thomas、Tanaka Hirohiko、Hayashi Yuki、Yoshida Naoaki、Nagata Daisuke、Vernimmen Jordy、Feng Shuangyuan、Zhang Rongshi、Ohno Noriyasu
  • Journal Title: Journal of Nuclear Materials Volume: 548 Pages: 152844-152844
  • DOI: 10.1016/j.jnucmat.2021.152844
  • NAID: 120007191867
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Effect of lithium vapour shielding on hydrogen plasma parameters (2021)
  • Author(s): Romano F、Rindt P、Scholten J、Hayashi Y、Morgan T W
  • Journal Title: Physica Scripta Volume: 96 Issue: 12 Pages: 125626-125626
  • DOI: 10.1088/1402-4896/ac2bde
  • Peer Reviewed / Open Access
• [Journal Article] Divertor heat load distribution measurements with infrared thermography in the LHD helical divertor (2021)
  • Author(s): Yuki Hayashi, Masahiro Kobayashi, Kiyofumi Mukai, Suguru Masuzaki, Takanori Murase, and the LHD Experiment Group
  • Journal Title: Fusion Engineering and Design Volume: 165 Pages: 112235-112235
  • DOI: 10.1016/j.fusengdes.2021.112235
  • NAID: 120007098360
  • Peer Reviewed
• [Presentation] Development and optimization of cascaded arc plasma source in TPD-II (2022)
  • Author(s): Yuki Hayashi, Yukinori Hamaji, Suguru Masuzaki, Naomichi Ezumi, Noriyasu Ohno, Shinichi Namba and Makoto Takagi
  • Organizer: ISPlasma 2022 / IC-PlANTS 2022
  • Int'l Joint Research
• [Presentation] Magnum-PSI 非接触プラズマにおけるリサイクリング粒子が熱パルス緩和に与える影響 (2021)
  • Author(s): 林祐貴, 田中宏彦, 大野哲靖, 梶田信 , T.W. Morgan, H.J. van der Meiden, J. Scholten, J.W.M. Vernimmen, 澤田圭司, 増田翔太, 夏目祥揮
  • Organizer: 第38回プラズマ・核融合学会年会
• [Presentation] Divertor Heat Flux Distribution Measurements in Radiative Divertor Operation in LHD (2021)
  • Author(s): Yuki Hayashi, Masahiro Kobayashi, Kiyofumi Mukai, Suguru Masuzaki, Takanori Murase, and the LHD Experiment Group
  • Organizer: 24th International Conference on Plasma Surface Interactions in Controlled Fusion Devices
  • Int'l Joint Research
• [Presentation] Study on heat pulse transport in detached recombining plasma in linear plasma device Magnum-PSI (2020)
  • Author(s): Yuki Hayashi, Hirohiko Tanaka, Shin Kajita, Noriyasu Ohno, Thomas Morgan, Hennie Meiden, John Scholten, and Jordy Vernimmen
  • Organizer: 29th International Toki Conference on Plasma and Fusion Research
  • Int'l Joint Research
• [Presentation] LHDヘリカルダイバータにおける赤外線サーモグラフィーを用いたダイバータ熱流束計測 (2020)
  • Author(s): 林 祐貴, 小林政弘, 向井清史, 増崎貴, LHD実験グループ
  • Organizer: 第37回プラズマ・核融合学会年会