2020 Fiscal Year Final Research Report
Development of a high-precision modulation-based plasma polarization spectroscopic system for the measurement of the electron velocity distribution
| Project/Area Number |
18K03576
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 14010:Fundamental plasma-related
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | ECH / 電子速度分布 / プラズマ分光 / 偏光 / 衝突輻射モデル / 輻射輸送 |
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| Outline of Final Research Achievements |
A polarization spectroscopic method that can measure anisotropy in the electron velocity distribution (EVD) was developed. A modulation spectroscopic system was developed to measure small polarization degree in emission lines, and it was confirmed that the polarization degree of less than 1% is detectable. Using the developed system, we measured the EVD near the ECR surface in a helium ECR plasma and confirmed that the EVD has larger average energy in the direction perpendicular to the magnetic field. Moreover, the polarization of hydrogen Balmer-alpha emission line was measured to apply the method to a wide range of plasmas. The polarization degree of up to about 1.5% was observed.
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| Free Research Field |
プラズマ分光学，光工学
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| Academic Significance and Societal Importance of the Research Achievements |
等方なマクスウェル分布からずれた非等方な電子の速度分布が関連するプラズマ現象が，近年，宇宙プラズマから産業応用プラズマまで数多く報告されている．これらの報告は，3次元の電子速度分布を基礎パラメータとして把握することが，プラズマ科学を発展させる鍵となることを示している．
電子速度分布の従来の計測法では，速度分布の非等方性の情報まで得ることは容易ではなく，また，接触計測の必要性やプラズマへの擾乱，レーザーや波動の入射・出射ポートの確保，計測可能なプラズマパラメータの制限といった課題がある．本研究では，原子から放射される発光線の偏光を利用し，幅広いパラメータのプラズマに適用可能な手法を開発した．
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