Clarification of dynamic interaction among turbulence, flow, and solitary eddy in a linear magnetized plasma

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K14897
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Nuclear fusion studies
• Research Institution: Shimane University (2018-2019); Teikyo University (2017)
• Principal Investigator: Arakawa Hiroyuki 島根大学, 学術研究院理工学系, 准教授 (00615106)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: プラズマ乱流 / 孤立渦 / 帯状流 / プラズマ計測 / レーザー誘起蛍光法

Outline of Final Research Achievements

In this study, we clarified dynamics among turbulence (drift wave type), flow (zonal flow) and a solitary eddy in a linear magnetized plasma. The solitary eddy is a perturbation with circumnavigating motion localized radially and azimuthally. The solitary eddy is organized/damped in synchronization with the phase modulation of the fundamental drift wave type mode and nonlinearly excited modes. The modes are modulated by the flow fluctuations. In addition, it was observed that a coherent structure with a shorter life and a larger wave number was formed at the formation of the solitary eddy. The amplitudes of particle transport by the solitary eddy and the coherent structure are close, which indicates that the coherent structure would have great impact on the turbulent transport.

Free Research Field

プラズマ物理学

Academic Significance and Societal Importance of the Research Achievements

本研究成果による、孤立渦形成機構の解明により、これまで考えられてきた乱流と流れの２体系の乱流物理理論を、孤立渦を加えた３体系に拡張する指標ができた。加えて、孤立渦に伴うコヒーレント構造の観測とこれらの輸送の評価により、４次的効果を含めた多体の乱流物理の重要性を示した。本研究成果を基礎として、核融合プラズマにおいても、閉じ込め改善・新しい制御手法の開発ができる可能性がある。加えて物理的共通点が知られている惑星流体等、中性乱流理論への寄与も期待できる。