Integrated multi-time-scale simulation of energetic ion dynamics in tokamak plasmas

2015 Fiscal Year Final Research Report

• Project/Area Number: 25820443
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Nuclear fusion studies
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: Bierwage Andreas 国立研究開発法人日本原子力研究開発機構, 核融合研究開発部門 六ヶ所核融合研究所, 研究副主幹 (10584691)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 核融合学 / トカマク / 高エネルギーイオン / アルフベン波 / 波・粒子共鳴 / マルチ時間スケール動力学 / 非線形シミュレーション

Outline of Final Research Achievements

A combination of integrated and self-consistent multi-time-scale simulations of beam-driven JT-60 tokamak plasmas were performed on the high-performance supercomputer Helios. These simulations reproduced, for the first time, experimentally observed relaxations known as Abrupt Large Events (ALE), which play an important role in the regulation of nuclear fusion performance and plasma confinement. An analysis of the results revealed key physics mechanisms that determine the intervals between ALEs and their sudden onset. In particular, the duration of the intervals is determined by collisional slow-down of energetic ions and wave-particle resonance conditions. The overlap of resonances associated with three distinct magnetohydrodynamic (MHD) modes is proposed as a key component of the ALE trigger mechanism. The numerical results were successfully validated against experimental data, which helps to build confidence in their relevance and reliability as needed for making predictions.

Free Research Field

工学