2005 Fiscal Year Final Research Report Summary
Quantization of precursor process of exfoliation dust occurrence
| Project/Area Number |
16560726
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nuclear fusion studies
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| Research Institution | National Institute for Fusion Science |
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Principal Investigator |
SAGARA Akio National Institute for Fusion Science, LHD project, Professor, 大型ヘリカル研究部, 教授 (20187058)
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| Co-Investigator(Kenkyū-buntansha) |
ASHIKAWA Naoko National Institute for Fusion Science, LHD project, Research Associate, 大型ヘリカル研究部, 助手 (00353441)
SHOJI Mamoru National Institute for Fusion Science, LHD project, Research Associate, 大型ヘリカル研究部, 助手 (00280602)
TOMITA Yukihiro National Institute for Fusion Science, Theory and Computer Simulation Center, Associate Professor, 理論・シミュレーション研究センター, 助教授 (40115605)
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| Project Period (FY) |
2004 – 2005
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| Keywords | dust / thin film / exfoliation / laser reflection / laser scattering / high-speed television camera / glow discharge / precursor |
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| Research Abstract |
The purpose is the quantization of precursor processes of exfoliation dust occurrence, aiming at the control of dust formation in plasma-wall interaction. The first stage of this research is device development in order to measure exfoliation of thin films and dust occurrence simultaneously under plasma irradiations. This device mainly consists of a polarized laser reflection to analyze film thickness and exfoliation, and a polarized light Mie scattering to measure the size distribution and spatial density of dust particle. Especially the real-time analysis with high-speed data processing of those measurements is the key to be established in this research. The second stage is to measure the precursor processes of exfoliation dust occurrence under various experimental parameters.
The first stage was achieved almost in the first year. Then the second stage was executed. Namely, (1)functional verification and noise reduction of the laser reflection device system, calibration and entire system adjustment using carbon particles, (2)the real-time film thickness measurement comparing with periodic oscillations and model calculations of laser surface reflectivity, (3)the real-time measurements of carbon film formation on SUS samples.
As the result, in methane mixed He glow discharges there is no remarkable change, but in several milli-sec to 2 sec immediately after the discharge stopping remarkable signs of dust occurrence were observed. Furthermore, under a quasi-static atmospheric introduction of 3 hours, remarkable signs of surface deformation and dust occurrence were observed, and in fact the exfoliation dusts around 10micrometer in diameter were identified by the SEM analysis. In conclusion, it has been firstly found that the direct microscopic measurements from outside the vacuum device are essentially important even for the open-to-air as future works.
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