We study the nonlinear coupling mechanism and turbulent transition in magnetically confined plasma flows based on two representative limiting regime dynamics. The two-field flux-balanced Hasegawa–Wakatani (BHW) model is taken as a simplified approximation to the key physical processes in the energy-conserving nonlinear plasma flows. The limiting regimes separate the effects of finite non-adiabatic resistivity and extreme non-normal dynamics to enable a more detailed investigation on each individual aspect with the help of various mathematical tools. We adopt the strategy from the selective decay theory used for the simpler one-field system to develop new crucial a priori estimations in the two-field model framework. The competing effects from model dissipation, finite particle resistivity, as well as the nonlinear interaction with a zonal mean state to induce dual direction energy transports are characterized from the systematic analysis. Non-normal dynamics with aligned eigendirections is also shown to go through a sharp transition from turbulence to regularized zonal flows. The diverse phenomena implied from the limiting regime analysis are further confirmed from direct numerical simulations of the BHW model.

中文翻译：

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等离子体边缘湍流极限态中的非线性相互作用和湍流过渡

我们基于两个有代表性的限制状态动力学研究了磁约束等离子体流的非线性耦合机制和湍流过渡。长谷川和谷谷两场通量平衡模型（BHW）被用作节能非线性等离子体流中关键物理过程的简化近似。限制制度将有限的非绝热电阻率和极端的非正态动力学的影响分开，以借助各种数学工具对每个方面进行更详细的研究。我们采用来自选择性衰减理论的策略，用于更简单的单场系统，以开发新的关键先验两场模型框架中的估计。通过系统分析来表征模型耗散，有限颗粒电阻率以及与纬向平均态的非线性相互作用引起的双向能量传输的竞争效应。特征方向对齐的非法向动力学也显示出从湍流到规则的纬向流的急剧转变。BHW模型的直接数值模拟进一步证实了极限状态分析所隐含的各种现象。