金属ナノ構造上で誘起されるアークプラズマの特性およびナノ構造の損耗に関する研究

• Project/Area Number: 17J05670
• Research Category: Grant-in-Aid for JSPS Fellows
• Allocation Type: Single-year Grants
• Section: 国内
• Research Field: Nuclear fusion studies
• Research Institution: Nagoya University
• Principal Investigator: 皇甫 度均 名古屋大学, 工学研究科, 特別研究員(DC1)
• Project Period (FY): 2017-04-26 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥2,800,000 (Direct Cost: ¥2,800,000); Fiscal Year 2019: ¥900,000 (Direct Cost: ¥900,000); Fiscal Year 2018: ¥900,000 (Direct Cost: ¥900,000); Fiscal Year 2017: ¥1,000,000 (Direct Cost: ¥1,000,000)
• Keywords: アーク / 核融合 / ナノ構造 / ヘリウムプラズマ / タングステン / ダイバータ / ステラレータ / アークプラズマ / プラズマ材料相互作用

Outline of Annual Research Achievements

１. Nano-tendril bundles(NTBs)構造の電界電子放出およびブレークダウン特性の評価：電界電子放出による電流変化はNTBsの形状や高さに依存し、数MV/mでブレークダウンが始まることを明らかにした。ブレークダウン後、NTBsの一部は完全に破壊されており、熱電界電子放出によるジュール加熱が原因であることが分かった。また、NTBが形成されたタングステン試料において過渡的熱負荷の印加が無くても自発的に誘起するアーキング現象が発見され、NTBsの電界電子放出の増大がアーキング誘起を容易にすることが示唆された。
２．磁場と垂直な表面上におけるアークプラズマの運動と分光計測：磁場と垂直な平面上で100に及ぶアークスポットが同時発生することを示し、そのミクロ運動はランダムである一方、マクロには拡散運動することを示した。また、基盤のナノ構造厚みによりスポット数、運動速度が変化することを明らかにした。一方、アークプラズマの分光計測によりアークプラズマの電子温度および電子密度を評価した。電子温度はナノ構造厚みを逆相関関係にあるのに対し、電子密度は正の相関をしました。サハーボルツマン方程式より、ナノ構造厚みが増すほどアークプラズマ中にW中性粒子の割合が増加し、電子温度の減少に寄与したことが示唆された。
３．大型核融合実験装置W7-Xにおけるアーク痕観察：ドイツの環状ステラレータW7-X内部調査を行い、プラズマ対向壁およびその基盤の表面上で発生したアーク痕を統計的に分析した。その結果、アーク痕のほとんどは主プラズマ運転の間に行うグロー放電洗浄時に発生したことが示唆された。一方、アーク痕は主としてプラズマ対向壁モジュールの縁や表面上に点在する堆積層から誘起された。

Research Progress Status

令和元年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和元年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] University of California San Diego(米国)
• [Int'l Joint Research] Max-Planck Institute for Plasma Physics(ドイツ)
• [Int'l Joint Research] Lebedev Physical Institute/Prokhorov General Physics Institute/Moscow Engineering Physics Institute(ロシア連邦)
• [Int'l Joint Research] University of Liverpool(英国)
• [Int'l Joint Research] UC San Diego(米国)
• [Int'l Joint Research] Lebedev Physical Institute/Prokhorov General Physics Institute(ロシア連邦)
• [Int'l Joint Research] Center for Energy Research/University of California San Diego(米国)
• [Journal Article] Inspection of Arc Trails Formed in Stellarator/Heliotron Devices W7-X and LHD (2020)
  • Author(s): HWANGBO Dogyun、KAJITA Shin、DHARD Chandra Prakash、TOKITANI Masayuki、KRAUSE Marco、NAUJOKS Dirk、MASUZAKI Suguru、KLOSE S?ren、OHNO Noriyasu、The W7-X Team
  • Journal Title: Plasma and Fusion Research Volume: 15 Issue: 0 Pages: 2402012-2402012
  • DOI: 10.1585/pfr.15.2402012
  • NAID: 130007840524
  • ISSN: 1880-6821
  • Year and Date: 2020-03-27
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Enhanced fuzzy tungsten growth in the presence of tungsten deposition (2020)
  • Author(s): McCarthy Patrick、Hwangbo Dogyun、Bilton Matthew、Kajita Shin、Bradley James W.
  • Journal Title: Nuclear Fusion Volume: 60 Issue: 2 Pages: 026012-026012
  • DOI: 10.1088/1741-4326/ab6060
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Dynamics of the changes in the parameters of the arc plasma during the destruction of a helium-induced tungsten fuzz by arc pulses (2020)
  • Author(s): Barengolts S.A.、Hwangbo D.、Kajita S.、Ohno N.、Frolova V.P.、Nikolaev A.G.、Oks E.M.、Shmelev D.L.、Tsventoukh M.M.、Yushkov G. Yu
  • Journal Title: Nuclear Fusion Volume: 60 Issue: 4 Pages: 044001-044001
  • DOI: 10.1088/1741-4326/ab73c3
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Inspection of W 7-X plasma-facing components after the operation phase OP1.2b: observations and first assessments (2020)
  • Author(s): Dhard C P、?k?slompolo S、Balden M、Baldzuhn J、Biedermann C、Br?uer T、Brezinsek S、Endler M、Hayashi Y、Hwangbo D、Kajita S、Krause M、Kornejew P、Masuzaki S、Mayer M、Motojima G、Naujoks D、Otte M、Rohde V、the W7-X Team
  • Journal Title: Physica Scripta Volume: T171 Pages: 014033-014033
  • DOI: 10.1088/1402-4896/ab4b3f
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Helium irradiation effects on the surface modification and recrystallization of tungsten (2020)
  • Author(s): Khan A、De Temmerman G、Kajita S、Greuner H、Balden M、Hunger K、Ohno N、Hwangbo D、Tomita Y、Tokitani M、Nagata D、Yajima M
  • Journal Title: Physica Scripta Volume: T171 Pages: 014050-014050
  • DOI: 10.1088/1402-4896/ab52c6
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Ignition and Behavior of Arc Spots on Helium Irradiated Tungsten Under Fusion Relevant Condition (2019)
  • Author(s): Kajita Shin、Hwangbo Dogyun、Ohno Noriyasu
  • Journal Title: IEEE Transactions on Plasma Science Volume: 47 Issue: 8 Pages: 3609-3616
  • DOI: 10.1109/tps.2019.2908193
  • Peer Reviewed
• [Journal Article] Ignition and Sustainment of Arcing on Nanostructured Tungsten Under Plasma Exposure (2019)
  • Author(s): Hwangbo Dogyun、Nishijima Daisuke、Kajita Shin、Doerner Russell P.、Barengolts Sergey A.、Tsventoukh Mikhail M.、Tanaka Hirohiko、Ohno Noriyasu
  • Journal Title: IEEE Transactions on Plasma Science Volume: 47 Issue: 8 Pages: 3617-3625
  • DOI: 10.1109/tps.2019.2910839
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Field Emission From Nanostructured Tendril Bundles (2019)
  • Author(s): Sinelnikov Dmitry、Bulgadaryan Daniel、Hwangbo Dogyun、Kajita Shin、Kurnaev Valery、Ohno Noriyasu
  • Journal Title: IEEE Transactions on Plasma Science Volume: 47 Issue: 11 Pages: 5186-5190
  • DOI: 10.1109/tps.2019.2942725
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Growth process of nano-tendril bundles with sputtered tungsten (2019)
  • Author(s): Hwangbo Dogyun、Kajita Shin、Tanaka Hirohiko、Ohno Noriyasu
  • Journal Title: Nuclear Materials and Energy Volume: 18 Pages: 250-257
  • DOI: 10.1016/j.nme.2019.01.008
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Ignition and Sustainment of Arcing on Nanostructured Tungsten under Plasma Exposure (2019)
  • Author(s): Hwangbo Dogyun、Nishijima Daisuke、Kajita Shin、Russell P. Doerner、Sergey A. Barengolts、Mikhail M. Tsventoukh、Tanaka Hirohiko、Ohno Noriyasu
  • Journal Title: IEEE Transactions on Plasma Science Volume: 印刷中
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Ignition and erosion of materials by arcing in fusion-relevant conditions (2018)
  • Author(s): Hwangbo Dogyun、Kajita Shin、Barengolts Sergey A.、Tsventoukh Mikhail M.、Kawaguchi Shota、Mesyats Vadim G.、Ohno Noriyasu
  • Journal Title: Contributions to Plasma Physics Volume: 58 Issue: 6-8 Pages: 608-615
  • DOI: 10.1002/ctpp.201700157
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Growth of nano-tendril bundles on tungsten with impurity-rich He plasmas (2018)
  • Author(s): Hwangbo Dogyun、Kajita Shin、Ohno Noriyasu、McCarthy Patrick、Bradley James W.、Tanaka Hirohiko
  • Journal Title: Nuclear Fusion Volume: 58 Issue: 9 Pages: 096022-096022
  • DOI: 10.1088/1741-4326/aacd1f
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Effect of the Nanostructured Layer Thickness on the Dynamics of Cathode Spots on Tungsten (2018)
  • Author(s): Barengolts Sergey A.、Mesyats Vadim G.、Tsventoukh Mikhail M.、Kajita Shin、Hwangbo Dogyun、Ohno Noriyasu
  • Journal Title: IEEE Transactions on Plasma Science Volume: 46 Issue: 11 Pages: 4044-4050
  • DOI: 10.1109/tps.2018.2859953
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Pulsation Effects of Incident Ion Energy on W Fuzz Growth (2018)
  • Author(s): KAJITA Shin、KAWAGUCHI Shota、HWANGBO Dogyun、TANAKA Hirohiko、OHNO Noriyasu
  • Journal Title: Plasma and Fusion Research Volume: 13 Issue: 0 Pages: 1205001-1205001
  • DOI: 10.1585/pfr.13.1205001
  • NAID: 130006434144
  • ISSN: 1880-6821
  • Peer Reviewed
• [Journal Article] Field Emission From Metal Surfaces Irradiated With Helium Plasmas (2017)
  • Author(s): Dogyun Hwangbo, Shin Kajita, Noriyasu Ohno, Dmitry Sinelnikov
  • Journal Title: IEEE Transactions on Plasma Science Volume: 45 Issue: 8 Pages: 2080-2086
  • DOI: 10.1109/tps.2017.2679211
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Erosion of nanostructured tungsten by laser ablation, sputtering and arcing (2017)
  • Author(s): Hwangbo Dogyun、Kawaguchi Shota、Kajita Shin、Ohno Noriyasu
  • Journal Title: Nuclear Materials and Energy Volume: 12 Pages: 386-391
  • DOI: 10.1016/j.nme.2017.03.004
  • Peer Reviewed / Open Access
• [Presentation] Arc behavior on tungsten nanostructure under helium plasma exposure (2019)
  • Author(s): D. Hwangbo, D. Nishijima, S. Kajita, R.P. Doerner, H. Tanaka and N. Ohno
  • Organizer: 34th International Conference on Phenomena in ionized Gases
  • Int'l Joint Research
• [Presentation] Inspection of arc trails formed in stellarator/heliotron devices W7-X and LHD (2019)
  • Author(s): D. Hwangbo, S. Kajita, C. P. Dhard, M. Tokitani, M. Krause, D. Naujoks, S. Masuzaki, N. Ohno, S. Klose and The W7-X team
  • Organizer: The 28th International Toki Conference on Plasma and Fusion Research
  • Int'l Joint Research
• [Presentation] ヘリウム照射ナノ構造タングステン上でのアークの運動計測 (2019)
  • Author(s): 皇甫度均、西島大輔、梶田信、R.P. Doerner、田中宏彦、大野哲靖
  • Organizer: 第36回プラズマ・核融合学会年会
• [Presentation] 不純物添加ヘリウムプラズマ照射によるタングステンnano-tendril bundlesの生成 (2018)
  • Author(s): 皇甫度均
  • Organizer: 第35回プラズマ・核融合学会年会
• [Presentation] Growth process of nano-tendril bundles with sputtered tungsten (2018)
  • Author(s): Hwangbo Dogyun
  • Organizer: 23rd International Conference on Plasma Surface Interactions in Controlled Fusion Devices
  • Int'l Joint Research
• [Presentation] Ignition and sustainment of arcing on nanostructured tungsten under plasma exposure (2018)
  • Author(s): Hwangbo Dogyun
  • Organizer: 28th International Symposium on Discharges and Electrical Insulation in Vacuum
  • Int'l Joint Research
• [Presentation] Ignition and sustainment of arcing on nanostructured tungsten with ambient plasma exposure (2018)
  • Author(s): Dogyun Hwangbo, Daisuke Nishijima, Sergey A. Barengolts, Mikhail M. Tsventoukh, Shin Kajita, Russell P. Doerner, Hirohiko Tanaka, Noriyasu Ohno
  • Organizer: 28th International Symposium on Discharges and Electrical Insulation in Vacuum
  • Int'l Joint Research
• [Presentation] Growth process of nano-tendril bundles with sputtered tungsten (2018)
  • Author(s): Dogyun Hwangbo, Shin Kajita, Hirohiko Tanaka and Noriyasu Ohno
  • Organizer: 23rd International Conference on Plasma Surface Interactions in Controlled Fusion Devices
  • Int'l Joint Research
• [Presentation] Ignition and Erosion of materials by arcing in fusion relevant conditions (2017)
  • Author(s): Dogyun Hwangbo, Shin Kajita, Shota Kawaguchi, Hirohiko Tanaka and Noriyasu Ohno
  • Organizer: 16th International Workshop on Plasma Edge Theory in Fusion Devices
  • Int'l Joint Research
• [Presentation] Growth of nano-tendril bundles on tungsten in impurity-rich helium plasmas (2017)
  • Author(s): Dogyun Hwangbo, Shin Kajita, Shota Kawaguchi, Hirohiko Tanaka and Noriyasu Ohno
  • Organizer: 33th The International Conference on Phenomena in Ionized Gases
  • Int'l Joint Research