Non-equilibrium plasma physics near criticality: phase-space cascades, wave-flow interactions, edge-of-chaos structures and turbulent transport

接近临界的非平衡等离子体物理：相空间级联、波流相互作用、混沌边缘结构和湍流传输

• 批准号: 2117056
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2117056
• 关键词: Non; equilibrium; plasma; physics; near

The question of how large a temperature difference can be maintained between the core and the edge of the plasma in a fusion machine opens a window onto some of the most fundamental theoretical questions about the structure of nonlinear, non-equilibrium states in magnetised plasma. These questions revolve around the ways in which free energy extracted from macroscopic inhomogeneities of the system (in the case of a fusion plasma, from the background temperature gradient) in the form of electromagnetic fluctuations is distributed in phase space (particles' positions and momenta) so as to give rise to a chaotic, multiscale (=turbulent) state that accommodates a steady flow of energy from macro to micro scales and its return to its inevitable resting place in the form of the thermal motion of the particles. This distribution of energy is then what determines how the turbulent plasma transports heat and momentum. This project's aim is to follow up on a number of recent developments in our understanding of these phenomena and investigate: the implications of the nonlinear suppression of energy flows into phase space [1,2] for transport models; the delicate balance between a chaotic field of plasma excitations ("drift waves") and self-generated regular "zonal" flows [3] that maintains the nonlinear state of a plasma near the critical threshold separating the turbulent and quiescent phases; the emergence of persistent coherent structures at this so-called "edge of chaos" [4] --- and how all this fits together and conspires to set limits on the background gradients. The project will have analytical, numerical and possibly experimental [5] components, depending on rate of progress and student's inclinations.1. A. A. Schekochihin et al., J. Plasma Phys. 82, 905820212 (2016)2. T. Adkins & A. A. Schekochihin, J. Plasma Phys. 84, 905840107 (2018)3. G. J. Colyer et al., Plasma Phys. Control. Fusion 59, 055002 (2017)4. F. van Wyk et al., J. Plasma Phys. 82, 905820609 (2016)5. M. F. J. Fox et al., Plasma Phys. Control. Fusion 59, 034002 (2017)

融合机中血浆之间的核心和边缘之间可以维持较大的温度差的问题，它将窗口打开一些关于磁性等离子体中非线性，非平衡状态结构的最基本理论问题。 These questions revolve around the ways in which free energy extracted from macroscopic inhomogeneities of the system (in the case of a fusion plasma, from the background temperature gradient) in the form of electromagnetic fluctuations is distributed in phase space (particles' positions and momenta) so as to give rise to a chaotic, multiscale (=turbulent) state that accommodates a steady flow of energy from macro to micro scales and its return to its不可避免的休息位置，颗粒的热运动形式。那么能量的分布是决定湍流等离子体如何运输热量和动量的原因。该项目的目的是跟进我们对这些现象的最新发展并进行了调查：非线性抑制能量流入相位空间[1,2]对运输模型的含义；血浆激发（“漂移波”）的混乱场与自我生成的常规“区域”流[3]之间的微妙平衡[3]，该流动在临界阈值附近保持血浆的非线性状态，从而将湍流和静态相分开；在这种所谓的“混乱的边缘” [4] ---以及所有这些如何拟合并密谋对背景梯度设置限制的所谓“ Chaos” [4] ---的出现。该项目将具有分析性，数值和可能的实验性[5]组成部分，具体取决于进步率和学生的倾向。1。 A. A. Schekochihin等人，J。PlasmaPhys。 82，905820212（2016）2。 T. Adkins和A. A. Schekochihin，J。PlasmaPhys。 84，905840107（2018）3。 G. J. Colyer等人，血浆Phys。控制。 Fusion 59，055002（2017）4。 F. van Wyk等人，J。PlasmaPhys。 82，905820609（2016）5。 M. F. J. Fox等人，血浆物理学。控制。 Fusion 59，034002（2017）