synergistic irradiation effects of laser pulses and plasmas to the materials with high melting point

• Project/Area Number: 19860090
• Research Category: Grant-in-Aid for Young Scientists (Start-up)
• Allocation Type: Single-year Grants
• Research Field: Nuclear fusion studies
• Research Institution: Nagoya University (2008); Japan Atomic Energy Agency (2007)
• Principal Investigator: KAJITA Shin Nagoya University, エコトピア科学研究所, 講師 (00455297)
• Project Period (FY): 2007 – 2008
• Project Status: Completed (Fiscal Year 2008)
• Budget Amount: ¥2,902,000 (Direct Cost: ¥2,530,000、Indirect Cost: ¥372,000); Fiscal Year 2008: ¥1,612,000 (Direct Cost: ¥1,240,000、Indirect Cost: ¥372,000); Fiscal Year 2007: ¥1,290,000 (Direct Cost: ¥1,290,000)
• Keywords: ヘリウム損傷 / 金属ミラー / 間欠的熱負荷 / プラズマ照射 / 複合照射効果 / 核融合プラズマ / レーザーアブレーション / レーザーアブレーシ

Research Abstract

ダイバータ模擬装置NAGDIS-II(名古屋大学)において、タングステンへのヘリウム照射を行った. He-NeレーザーとPin-Photodiodeを組み合わせ、in situでの反射率計測機器を構築し、プラズマ照射に伴うタングステンの反射率変化を調べた. ナノ秒レーザー及びサブミリ秒レーザーを用いたアブレーションを、高速カメラとフィルタを組み合わせたフィルタ分光法を用いて調べた. プラズマとレーザーの複合照射によりアブレーション閾値が著しく減少することが明らかになった.

Research Products

• [Journal Article] Prompt ignition of a unipolar arc on helium irradiated tungsten (2009)
  • Author(s): Shin Kajita, Shuichi Takamura, Noriyasu Ohno
  • Journal Title: Nuclear Fusion Vol. 49
  • Peer Reviewed
• [Journal Article] Visualized Blow-off from helium irradiated tungsten in response to ELM-like heat load (2009)
  • Author(s): Shin Kajita, Noriyasu Ohno, Wataru Sakaguchi, Makoto Takagi
  • Journal Title: Plasma and Fusion Research Vol.4
  • NAID: 130000103677
  • Peer Reviewed
• [Journal Article] Prompt ignition of a unipolar arc on helium irradiated tungsten (2009)
  • Author(s): Shin Kajita, et al.
  • Journal Title: Nuclear Fusion 49 Pages: 261501-261501
  • Peer Reviewed
• [Journal Article] Visualized Blow-off from helium irradiated tungsten in response to ELM-like heat load (2009)
  • Author(s): Shin Kajita, et al.
  • Journal Title: Plasma and Fusion Research 4 Pages: 4-4
  • NAID: 130000103677
  • Peer Reviewed
• [Journal Article] Design Study of Polychromators for ITER Edge Thomson Scattering Diagnostics (2008)
  • Author(s): Shin Kajita, et al.
  • Journal Title: Review of Scientific Instruments 79
  • NAID: 120006763952
  • Peer Reviewed
• [Journal Article] Assessment of Laser Transrson Mirror for ITER Edge Thom son Scattering Diagnostics (2008)
  • Author(s): Shin Kajita, Takaki Hatae, V. S. Voitsenya
  • Journal Title: Plasma and Fusion Research 3 Pages: 32-32
  • Peer Reviewed
• [Journal Article] Plasma-assisted laser ablation of tungsten : Reduction in ablation power threshold due to bursting of holes/bubbles (2007)
  • Author(s): Shin Kajita, Noriyasu Ohno, Shuichi Takumura, Wataru Sakaguchi, Dai Nishijima
  • Journal Title: Applied Physics Letters Vol. 91
  • NAID: 120006733926
  • Peer Reviewed
• [Journal Article] Plasma-assisted laser ablation of tungsten: Reduction in ablation power threshold due tobursting of holes/bubbles (2007)
  • Author(s): S. Kajita, N. Ohno, S. Takumura, W. Sakaguchi, D. Nishijima
  • Journal Title: Applied Physics Letters 91
  • Peer Reviewed
• [Journal Article] Formation and mitigation of fiberform nanostructured tungsten by helium and sub-ms laser pulse irradiations
  • Author(s): Shin Kajita, Wataru Sakaguchi, Noriyasu Ohno
  • Journal Title: Plasma Devices and Operations (in press)
  • Peer Reviewed
• [Journal Article] In situ reflectivity of tungsten mirrors under helium plasma exposure
  • Author(s): Wataru Sakaguchi, Shin Kajita, Noriyasu Ohno, Makoto Takagi
  • Journal Title: Journal of Nuclear Materials (in press)
  • Peer Reviewed
• [Presentation] タングステンへのレーザーとヘリウムプラズマの照射効果プラズマ科学シンポジウム2009 (2009)
  • Author(s): 梶田信、大野哲靖、坂口亙
  • Organizer: 第26回プラズマプロセシング研究会
  • Place of Presentation: 名古屋
  • Year and Date: 2009-02-03
• [Presentation] Formation condition of fiberform nanostructured tungsten by helium plasma irradiation (2009)
  • Author(s): W.Sakaguchi, S.Kajita, N.Ohno, M.Takagi
  • Organizer: IC-PLANTS 2009
  • Place of Presentation: Nagoya, Japan
  • Year and Date: 2009-01-23
• [Presentation] ヘリウムプラズマ照射によるタングステンナノ構造の形成条件 (2008)
  • Author(s): 坂口亙、梶田信、大野哲靖、高木誠
  • Organizer: 第25回プラズマ・核融合学会年会
  • Place of Presentation: 宇都宮
  • Year and Date: 2008-12-05
• [Presentation] タングステンへのプラズマ・レーザー複合照射効 (2008)
  • Author(s): 梶田信、大野哲靖、坂口亙
  • Organizer: 第25回プラズマ・核融合学会年会
  • Place of Presentation: 宇都宮
  • Year and Date: 2008-12-02
• [Presentation] タングステンへのプラズプラズマ・レーザー複合照射効果 (2008)
  • Author(s): 梶田信
  • Organizer: 第25回プラズマ・核融合学会年会
  • Place of Presentation: 宇都宮
  • Year and Date: 2008-12-02
• [Presentation] Irradiation Effects of helium and laser on in-vessel mirror material (2008)
  • Author(s): S. Kajita
  • Organizer: International Workshop on Microwave-Laser diagnostics and particle-Mirror interaction for burning plasma experiment
  • Place of Presentation: Shikano-shima, Japa
  • Year and Date: 2008-09-13
• [Presentation] Spectroscopy Study of High Z Material Ablation Phenomena under Helium Plasma Exposure (2008)
  • Author(s): W.Sakaguchi, S.Kajita, N.Ohno, M.Takagi
  • Organizer: 18th PSI Conference
  • Place of Presentation: Toledo, Spain
  • Year and Date: 2008-05-29
• [Presentation] Design Stody of Polychromators for ITER Edge Thomson Scattering Diagnostics (2008)
  • Author(s): 梶田信
  • Organizer: 17th Topical Conference on High-Temperature Pl asma Diagnostics
  • Place of Presentation: アルバーカーキ, ニューメキシコ(米国)
  • Year and Date: 2008-05-13
• [Presentation] ヘリウムプラズマ照射下における高Z材のアブレーション現象の観測 (2008)
  • Author(s): 坂口 亙、梶田 信、大野哲靖、高木 誠
  • Organizer: 電気学会全国大会
  • Place of Presentation: 福岡工業大学
  • Year and Date: 2008-03-21