Introduction to the interaction between energetic particles and Alfven eigenmodes in toroidal plasmas
Introduction to the interaction between energetic particles and Alfven eigenmodes in toroidal plasmas
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DOI：
10.1007/s41614-018-0022-9
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发表时间：
2018-12
期刊：
影响因子：
--
通讯作者：
Y. Todo
中科院分区：
文献类型：
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作者：
Y. Todo
高能粒子与Alfvén本征模的相互作用是聚变燃烧等离子体的重要研究课题之一。声发射的失稳机制是通过与高能粒子的共振相互作用产生的一种逆朗道阻尼。解释了声发射不稳定性的一些重要性质，如共振条件、相互作用中的守恒变量以及声发射对粒子的捕获等。声发射的时间演化可分为稳态、频率分裂、频率啁啾和周期性爆发等多种类型。Berk和Breizman提出了一个一维弱非线性边际稳定性理论和一个简化的模拟模型，定性地解释了各种类型的时间演化。本文介绍了Berk-Breizman的理论和简化的仿真模型，并讨论了它们的局限性和未来的工作。此外，高能粒子运输AE说明与表面的部分图。由AE捕获的粒子产生相空间岛，并导致高能粒子空间轮廓的局部平坦化。多个声发射的共振重叠和单个声发射的高阶共振重叠导致相空间中随机性的出现和高能粒子的全局输运。
This article is a tutorial review of the interaction between energetic particles and Alfvén eigenmodes (AEs) which is one of the important research issues for fusion burning plasmas. The destabilization mechanism of AEs is a kind of inverse Landau damping through the resonant interaction with energetic particles. The important properties of the AE instability, such as resonance condition, conserved variable during the interaction, and particle trapping by the AE, are explained. The time evolution of AEs is classified into various types, steady state, frequency splitting, frequency chirping, and recurrent bursts. Berk and Breizman presented both a one-dimensional weakly nonlinear theory for marginal stability and a reduced simulation model that qualitatively explain the various types of time evolution. Berk–Breizman’s theory and reduced simulation model are introduced, and their limitations and the future works are discussed in this article. In addition, energetic particle transport by AEs is illustrated with surface-of-section plots. The particle trapping by the AE creates phase space islands and leads to the local flattening of the energetic particle spatial profile. The resonance overlap of multiple AEs and the overlap of higher-order resonances of a single AE lead to the emergence of stochasticity in phase space and the global transport of energetic particles.