Effects of impurity screening by stochastic magnetic field on tungsten transport in ITER edge plasmas

• Project/Area Number: 17K14426
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Plasma science
• Research Institution: National Institute for Fusion Science
• Principal Investigator: Oishi Tetsutarou 核融合科学研究所, ヘリカル研究部, 助教 (80442523)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
• Keywords: 不純物輸送 / タングステン / 真空紫外分光 / ITER / 周辺プラズマ / プラズマ・核融合

Outline of Final Research Achievements

The impurity screening effect is caused by the edge stochastic magnetic field layer in magnetically-confined plasmas. In this study, the experimental conditions in which the impurity screening is effective on the tungsten ions were explored in the Large Helical Device (LHD). Plasma discharge parameter survey on sustain or collapse against tungsten injection, experimental verification on a theoretical impurity transport model based on the parallel momentum balance, and multi-wavelength spectroscopic diagnostics for tungsten ions from low to high charge states were conducted.

Academic Significance and Societal Importance of the Research Achievements

タングステンが不純物イオンとしてプラズマ中に蓄積すると，74という高原子番号のため線放射によるエネルギー損失が大きくなる．この蓄積現象は，タングステンが金属表面から中性原子として放出され，低温の周辺プラズマで低電離状態のイオンとして輸送され，高温のコアプラズマに高電離状態のイオンとして蓄積する，という過程を経由する．従って，周辺プラズマにおける不純物遮蔽現象がタングステンの輸送に及ぼす影響の研究は，タングステン蓄積の制御へ向けた可能性を開拓するものである．

Research Products

• [Int'l Joint Research] ASIPP(中国)
• [Journal Article] Doppler profile diagnostics on VUV spectra for the impurity ion temperature in edge plasmas of Large Helical Device (2019)
  • Author(s): T.Oishi, S.Morita, S.Y.Dai, M.kobayashi, G.Kawamura, Y.Liu and M.Goto
  • Journal Title: Journal of Physics Conference Series Volume: 1289 Issue: 1 Pages: 012037-012037
  • DOI: 10.1088/1742-6596/1289/1/012037
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Response of Plasmas to Tungsten Pellet Injection in Neutral Beam Heated Discharges in Large Helical Device (2018)
  • Author(s): OISHI Tetsutarou、MORITA Shigeru、HUANG Xianli、LIU Yang、GOTO Motoshi、the LHD Experiment Group
  • Journal Title: Plasma and Fusion Research Volume: 13 Issue: 0 Pages: 3402031-3402031
  • DOI: 10.1585/pfr.13.3402031
  • NAID: 130007396443
  • ISSN: 1880-6821
  • Year and Date: 2018-04-24
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Observation of carbon impurity flow in the edge stochastic magnetic field layer of Large Helical Device and its impact on the edge impurity control (2017)
  • Author(s): Oishi T.、Morita S.、Dai S.Y.、Kobayashi M.、Kawamura G.、Huang X.L.、Zhang H.M.、Liu Y.、Goto M.、the LHD Experiment Group
  • Journal Title: Nuclear Fusion Volume: 58 Issue: 1 Pages: 016040-016040
  • DOI: 10.1088/1741-4326/aa8f63
  • NAID: 120007119914
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Effect of impurity source locations on up-down asymmetry in impurity distributions in the ergodic layer of large helical device (2017)
  • Author(s): Oishi Tetsutarou、Morita Shigeru、Huang Xianli、Zhang Hongming、Liu Yang、Dai Shuyu、Kobayashi Masahiro、Kawamura Gakushi、Goto Motoshi
  • Journal Title: Nuclear Materials and Energy Volume: 12 Pages: 762-767
  • DOI: 10.1016/j.nme.2017.04.002
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] LHDの真空紫外波長域における高電離タングステンイオンの禁制線の探索 (2020)
  • Author(s): 大石鉄太郎，森田繁，加藤太治，村上泉，坂上裕之，川本靖子，後藤基志，LHD実験グループ
  • Organizer: 日本物理学会第７５回年次大会
• [Presentation] Temporal Evolution of Emissions from Tungsten Ions in Various Charge States Observed in Impurity Pellet Injection Experiments in Large Helical Device (2019)
  • Author(s): T. Oishi, S. Morita, D. Kato, I. Murakami, H. A. Sakaue, Y. Kawamoto, M. Goto and the LHD Experiment group
  • Organizer: The 28th International Toki Conference on Plasma and Fusion Research
  • Int'l Joint Research
• [Presentation] Study of Impurity Transport in Deuterium and Hydrogen Plasmas in the Edge Stochastic Magnetic Field Layer of Large Helical Device (2019)
  • Author(s): T. Oishi, S. Morita, M. Kobayashi, G. Kawamura, Y. Kawamoto, M. Goto and the LHD Experiment Group
  • Organizer: 46th European Physical Society Conference on Plasma Physics (EPS2019)
  • Int'l Joint Research
• [Presentation] LHDの周辺部統計的磁場領域での不純物輸送における背景プラズマの同位体効果 (2019)
  • Author(s): 大石鉄太郎，森田繁，小林政弘，河村学思，川本靖子，後藤基志，LHD実験グループ
  • Organizer: 日本物理学会２０１９年秋季大会
• [Presentation] LHDの周辺部統計的磁場領域における不純物遮蔽効果への重水素プラズマの影響 (2019)
  • Author(s): 大石鉄太郎，森田繁，小林政弘，河村学思，川本靖子，後藤基志，LHD実験グループ
  • Organizer: 日本物理学会第７４回年次大会
• [Presentation] Study of Carbon Impurity Transport in Deuterium and Hydrogen Plasmas in the Edge Ergodic Layer of Large Helical Device (2018)
  • Author(s): T. Oishi, S. Morita, M. Kobayashi, G. Kawamura, Y. Liu, Y. Kawamoto, M. Goto and the LHD Experiment group
  • Organizer: The 27th International Toki Conference on Plasma and Fusion Research & The 13th Asia Pacific Plasma Theory Conference
  • Int'l Joint Research
• [Presentation] Effect of deuterium plasmas on carbon impurity transport in the edge stochastic magnetic field layer of Large Helical Device (2018)
  • Author(s): T. Oishi, S. Morita, M. Kobayashi, G. Kawamura, Y. Liu, M. Goto and the LHD Experiment group
  • Organizer: The 27th IAEA Fusion Energy Conference
  • Int'l Joint Research
• [Presentation] Doppler Profile Diagnostics on VUV Spectra for Emission Intensity, Ion Temperature and Flow Velocity of Impurity Ions in Edge Plasmas of Large Helical Device (2018)
  • Author(s): Tetsutarou Oishi, Shigeru Morita, Yang Liu, Motoshi Goto and the LHD Experiment Group
  • Organizer: 24th International Conference on Spectral Line Shapes
  • Int'l Joint Research
• [Presentation] LHDの統計的磁場領域がもたらす 不純物制御の新展開 (2018)
  • Author(s): 大石鉄太郎，森田繁，戴舒宇，小林政弘，河村学思，劉洋，川本靖子，後藤基志，LHD実験グループ
  • Organizer: プラズマ・核融合学会第３５回年会
  • Invited
• [Presentation] LHDの周辺部統計的磁場領域における炭素不純物フローへの重水素プラズマの影響 (2018)
  • Author(s): 大石鉄太郎，森田繁，小林政弘，河村学思，劉洋，川本靖子，後藤基志，LHD実験グループ
  • Organizer: 日本物理学会２０１８年秋季大会
• [Presentation] LHDの周辺部統計的磁場領域における炭素不純物フローの不純物輸送への影響 (2018)
  • Author(s): 大石鉄太郎，森田繁，戴舒宇，小林政弘，河村学思，劉洋，後藤基志，LHD実験グループ
  • Organizer: 日本物理学会第７３回年次大会
• [Presentation] Response of plasmas to tungsten pellet injection in neutral beam heated discharges in Large Helical Device (2017)
  • Author(s): T. Oishi, S. Morita, X. L. Huang, Y. Liu, M. Goto and the LHD Experiment group
  • Organizer: Joint meeting of the 26th International Toki Conference (ITC-26) and The 11th Asia Plasma and Fusion Association Conference
  • Int'l Joint Research
• [Presentation] Observation of carbon impurity flow in the edge stochastic magnetic field layer of Large Helical Device and its dependence on the magnetic field configuration (2017)
  • Author(s): Tetsutarou Oishi, Shigeru Morita, Shuyu Dai, Masahiro Kobayashi, Gakushi Kawamura, Xianli Huang, Yang Liu, Motoshi Goto and the LHD Experiment group
  • Organizer: Plasma Conference 2017 (PLASMA2017)
  • Int'l Joint Research
• [Remarks] 研究活動状況 プラズマから「流れ去る」不純物－不純物遮蔽効果の分光計測による観測－
  • URL: http://www.nifs.ac.jp/lhdreport/mailinfo_297.html