Simulation study on impact of toroidal rotation on L-H transition

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K18342
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Nuclear fusion studies
• Research Institution: National Institutes for Quantum and Radiological Science and Technology
• Principal Investigator: Seto Haruki 国立研究開発法人量子科学技術研究開発機構, 六ヶ所核融合研究所 核融合炉システム研究開発部, 主任研究員(任常) (90733692)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: L-H遷移 / プラズマ乱流 / 径電場 / 数値シミュレーション / 周辺プラズマ安定性 / トカマクプラズマ

Outline of Final Research Achievements

For more quantitative understanding of the mechanism of L-H transition (a bifurcation phenomenon that improves plasma confinement performance) in high-beta magnetic confinement fusion devices such as ITER and DEMO, a numerical calculation code that can self-consistently simulate macroscopic electromagnetic field non-linearly generated by plasma turbulence is developed. Here a self-consistent interplay between macroscopic electromagnetic field and turbulence plays important role in numerical simulation of L-H transition.
As a proof of principle of the code, simulations of pedestal collapse are carried out. Here, the term "pedestal collapse" means a relaxation of steep plasma profile in the edge region in high confinement discharge due to edge localized modes. It is revealed that subsequent small energy releases triggered by an interplay between macroscopic electromagnetic field and plasma turbulence are observed after the primary pedestal collapse and rise energy loss level.

Free Research Field

核融合理論・シミュレーション

Academic Significance and Societal Importance of the Research Achievements

L-H遷移の数値シミュレーションに必要となる微視的なプラズマ乱流とプラズマ乱流から生成される巨視的な流れと磁場から構成されるマルチスケールの物理を自己無撞着に取り扱う数値手法を本課題では開発した。マルチスケールの物理を取り扱う数値手法の構築はプラズマ科学全般において非線形物理を取り扱う上で重要であり、他のプラズマシミュレーション研究への展開が期待できる。