Theory of the momentum flux probability distribution function for drift wave turbulence
Theory of the momentum flux probability distribution function for drift wave turbulence
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漂移波湍流动量通量概率分布函数理论
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
P. Diamond
中科院分区：
文献类型：
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作者：
Eun Jin Kim;P. Diamond
本文给出了强迫Hasegawa-Mima湍流中局部雷诺应力（R）概率分布函数（PDF）尾部的解析理论。PDF尾被视为一个过渡振幅从初始状态，没有流体运动，最终状态与不同的R值，由于非线性相干结构在长的时间限制。由于模型假设非线性结构是空间中的modon（非线性Hasegawa-Mima方程的精确解），该跃迁幅度由瞬子决定。瞬子在时间上是局部化的，并且可以与被认为是造成PDF尾部的突发和间歇事件相关联。瞬子是通过鞍点法应用于PDF，由路径积分表示。这意味着R的PDF尾部具有特定的形式exp[− cR 3/2]，这是一个拉伸的非高斯指数。
An analytical theory of the tails of the probability distribution function (PDF) for the local Reynolds stress (R) is given for forced Hasegawa–Mima turbulence. The PDF tail is treated as a transition amplitude from an initial state, with no fluid motion, to final states with different values of R due to nonlinear coherent structures in the long time limit. With the modeling assumption that the nonlinear structure is a modon (an exact solution of a nonlinear Hasegawa–Mima equation) in space, this transition amplitude is determined by an instanton. An instanton is localized in time and can be associated with bursty and intermittent events which are thought to be responsible for PDF tails. The instanton is found via a saddle-point method applied to the PDF, represented by a path integral. It implies the PDF tail for R with the specific form exp[−cR3/2], which is a stretched, non-Gaussian exponential.