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arXiv 1909.05066physics.plasm-phphysics.flu-dyn
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作为有效量子等离子体不稳定性的turbulence结构形成

Structure formation in turbulence as instability of effective quantum plasma

Vasileios Tsiolis, Yao Zhou, Ilya Y. Dodin

摘要:

湍流中的结构形成实际上是由作为粒子的波动形成的“等离子体”的不稳定性。这些“粒子”是类量子的;也就是说,它们的波长与背景相干结构的大小相比是不可忽略的。相应的“动力学方程”描述了湍流场的维格纳矩阵,相干结构充当集体场。这种形式主义通常适用于明显的类量子波或标量波。在这里,我们将其扩展到可压缩的Navier-Stokes湍流,波动哈密顿量是一个五维矩阵算子和不同的调制模式。作为一个例子,我们计算这些模式的正弦剪切流,并找到两个调制不稳定性。其中之一是特定的超音速流,另一个是开尔文-亥姆霍兹型不稳定性,这是一个推广的已知的纬向不稳定性。这项工作作为一个垫脚石,朝着提高磁流体动力学湍流的理解,这可以接近类似。

英文摘要:

Structure formation in turbulence is effectively an instability of "plasma" formed by fluctuations serving as particles. These "particles" are quantumlike; namely, their wavelengths are non-negligible compared to the sizes of background coherent structures. The corresponding "kinetic equation" describes the Wigner matrix of the turbulent field, and the coherent structures serve as collective fields. This formalism is usually applied to manifestly quantumlike or scalar waves. Here, we extend it to compressible Navier--Stokes turbulence, where the fluctuation Hamiltonian is a five-dimensional matrix operator and diverse modulational modes are present. As an example, we calculate these modes for a sinusoidal shear flow and find two modulational instabilities. One of them is specific to supersonic flows, and the other one is a Kelvin--Helmholtz-type instability that is a generalization of the known zonostrophic instability. This work serves as a stepping stone toward improving the understanding of magnetohydrodynamic turbulence, which can be approached similarly.

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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