Physical Plasma model research for radio-frequency electromagnetic analysis on plasma peripheral region

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K06944
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Nuclear fusion studies
• Research Institution: National Institute for Fusion Science
• Principal Investigator: KASAHARA Hiroshi 核融合科学研究所, ヘリカル研究部, 准教授 (50435517)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 周辺部のプラズマ物理モデル / 高周波電場 / 波動計算

Outline of Final Research Achievements

In order to make a physical model with high power radio-frequency electric-field on peripheral region of plasma, a multi-array electrostatic probe and high-frequency magnetic probe was designed and plasma measurements were performed. In actual plasma measurement, the measurement probe has strong damaged by the coupled electric field of excited radio-frequency, a large number of dielectric breakdowns had been occurred at the feedthrough part of the probe, and a non-contact measurement method is required to perform high-power radio-frequency electric field measurement. The need to develop feedthroughs for radio frequency measurement with high-voltage has increased.On excited wave patterns around the excitation antenna, cold plasma model and actual measurement agree well, qualitatively. However, the existence of equipment in vacuum vessel cause a density distribution associated with these equipment.

Free Research Field

高周波プラズマ

Academic Significance and Societal Importance of the Research Achievements

高周波を用いたプラズマ研究は周辺プラズマから核融合プラズマまで幅広く行われている。特にプラズマ点火や維持のために高周波を用いたプラズマ加熱に焦点が充てられ研究されているが、プラズマ周辺部の低密度域におけるプラズマ壁相互作用や低密度域における非伝搬領域での電磁波の伝搬が観測されていた。今回の研究で電磁波の伝搬としては冷たいプラズマモデルで十分なモデル形成が可能であることが分かったが、その反面、計測機器や電磁波励起用アンテナがもたらす密度分布形成のモデル化の重要性が明らかになった。