Characterization of Unipolar Arcing Initiated on Materials Exposed to Helium Plasmas

2014 Fiscal Year Final Research Report

• Project/Area Number: 23686133
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Nuclear fusion studies
• Research Institution: Nagoya University
• Principal Investigator: KAJITA Shin 名古屋大学, エコトピア科学研究所, 准教授 (00455297)
• Project Period (FY): 2011-04-01 – 2015-03-31
• Keywords: ナノ構造 / タングステン / アーキング

Outline of Final Research Achievements

To investigate the influence of arcing in the nuclear fusion reactor, experiments were conducted to reveal the effect and conditions of arcing. Material properties of nanostructured tungsten (W) was evaluated, and the influence of arcing in a large experimental reactor JT-60U was investigated. To discuss the initial process of arcing, the effects of helium irradiation on the field electron emission characteristics were experimentally investigated. The motion and the temperature of the generated plasma around the cathode spot were revealed from analysis of arc trail and spectroscopic measurement. The temperature was ~0.8 eV, and the fractal feature of arc spot motion was revealed. In addition, it was shown that the erosion rate of W was about 0.1 mg/C on the nanostructured W.

Free Research Field

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