Investigation of plasma confinement transition in toroidal system by active control of poloidal flow

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K03911
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 14020:Nuclear fusion-related
• Research Institution: National Institute for Fusion Science
• Principal Investigator: Takahashi Hiromi 核融合科学研究所, ヘリカル研究部, 准教授 (00462193)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 電極バイアス / ポロイダル粘性 / 径電場 / 閉じ込め改善 / 核融合プラズマ

Outline of Final Research Achievements

For the control of electric field and viscosity in toroidal field devices, construction of an electrode biasing system and electric field control experiments were carried out in the TJ-II in Spain. Although there were delays in the plan due to COVID-19, the unexpected results were obtained, including the observation of differences in the effects of electrode bias on ExB transport due to turbulence and ExB transport due to AE modes. In addition, in a rotational transformation scan experiment under electrode biasing, it was found that the poloidal flow velocity (radial electric field) has a radial structure that is clearly related to the rotational transform profile, especially the low-order rational surface. Furthermore, in order to further develop this research in the future, we have spearheaded a programme of controlled electric field experiments on the CFQS at Southwest Jiaotong University, China.

Free Research Field

プラズマ物理学

Academic Significance and Societal Importance of the Research Achievements

制御熱核融合炉の実現を指向とするトロイダル磁場閉じ込めプラズマ研究領域において、プラズマ中の電場、あるいは、フローはプラズマの熱閉じ込め性能を決定づける最も重要な物理量である。本研究において、電極バイアスによる電場制御下における特徴的な輸送の振る舞いや、磁場構造に強く関連したプラズマの構造形成を観測した。これらの研究成果は実験を行ったTJ-II装置でのみ得られたものであるが、今後、閉じ込め磁場構造の異なる他のプラズマ実験装置において、実験結果の蓄積とデータベース化を行い、メカニズムの定式化ができれば、電場やフロー、さらには、閉じ込め性能を機能的に制御する手段の確立につながる。