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arXiv 1809.06368physics.plasm-ph
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等离子体鞘层和不稳定性的连续动力学模拟

Continuum Kinetic Simulations of Plasma Sheaths and Instabilities

Petr Cagas

摘要:

仔细研究等离子体-材料相互作用对于理解和改进等离子体接触壁的设备的操作是必不可少的。这项工作的主要贡献包括(i)新的连续动力学算法与新的边界条件,直接离散的弗拉索夫/玻尔兹曼方程使用不连续Galerkin方法,(ii)等离子体鞘物理的基础研究与碰撞,电离和基于物理的壁发射,和(iii)动力学韦伯不稳定性的线性增长和非线性饱和的理论和数值研究,包括其在等离子体鞘中的作用。连续动力学算法已被证明是比较好的朗缪尔波的朗道阻尼和双流不稳定性的理论预测。基准也进行了电磁韦伯不稳定性和良好的协议之间的理论和模拟。电场的作用是显着的非线性饱和的韦伯不稳定性,这是没有注意到在以前的研究。重点放在了解等离子体鞘层物理是必不可少的研究等离子体-材料相互作用。初始模拟使用无碰撞模型来匹配经典鞘层理论和玻姆准则。介绍了碰撞算子和基于体积物理的源项,并简要讨论了热通量的影响。新的物理为基础的边界条件的开发和包括在一般的方式与连续动力学算法有界等离子体模拟。这是第一个连续动力学模拟使用自洽,壁发射边界条件,具有广泛的适用性,在各种制度。

英文摘要:

A careful study of plasma-material interactions is essential to understand and improve the operation of devices where plasma contacts a wall. Key contributions of this work include (i) novel continuum kinetic algorithms with novel boundary conditions that directly discretize the Vlasov/Boltzmann equation using the discontinuous Galerkin method, (ii) fundamental studies of a plasma sheath physics with collisions, ionization, and physics-based wall emission, and (iii) theoretical and numerical studies of the linear growth and nonlinear saturation of the kinetic Weibel instability, including its role in plasma sheaths. The continuum kinetic algorithm has been shown to compare well with theoretical predictions of Landau damping of Langmuir waves and the two-stream instability. Benchmarks are also performed using the electromagnetic Weibel instability and excellent agreement is found between theory and simulation. The role of the electric field is significant during nonlinear saturation of the Weibel instability, which was not noted in previous studies. A focus is put on understanding plasma sheath physics which is essential for studying plasma-material interactions. Initial simulations are performed using a collisionless model to match classical sheath theory and the Bohm criterion. A collision operator and volumetric physics-based source terms are introduced and effects of heat flux are briefly discussed. Novel physics-based boundary conditions are developed and included in a general manner with the continuum kinetic algorithm for bounded plasma simulations. These are the first continuum kinetic simulations using self-consistent, wall emission boundary conditions with broad applicability across a variety of regimes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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