论文标题
模型降低湍流的边缘性问题
The Problem of Marginality in Model Reductions of Turbulence
论文作者
论文摘要
降低的准线性（QL）和非线性（梯度驱动）模型具有比例分离的模型，通常用于解释实验，并预测磁化等离子体中的湍流传输水平，对没有规模分离的非线性模型进行了测试（Flux-drux驱动）。通过Boltzmann电子研究了两个不同的湍流机制 - 远高于阈值或接近边际稳定性。还原模型的成功，尤其是取决于非线性通量的繁殖。模型之间的良好一致性在阈值以上，而减少的模型将大大低估边缘性的通量，俯瞰中尺度流动组织和湍流自变量。讨论了改善减少模型的建设性处方。
Reduced quasilinear (QL) and nonlinear (gradient-driven) models with scale separations, commonly used to interpret experiments and to forecast turbulent transport levels in magnetised plasmas are tested against nonlinear models without scale separations (flux-driven). Two distinct regimes of turbulence -- either far above threshold or near marginal stability -- are investigated with Boltzmann electrons. The success of reduced models especially hinges on the reproduction of nonlinear fluxes. Good agreement between models is found above threshold whilst reduced models would significantly underpredict fluxes near marginality, overlooking mesoscale flow organisation and turbulence self-advection. Constructive prescriptions whereby to improve reduced models is discussed.
