Effects of parallel dynamics on vortex structures in electron temperature gradient driven turbulence
Effects of parallel dynamics on vortex structures in electron temperature gradient driven turbulence
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DOI：
10.1063/1.3535584
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发表时间：
2011-01
影响因子：
2.2
通讯作者：
M. Nakata;Tomo-Hiko Watanabe;H. Sugama;W. Horton
中科院分区：
文献类型：
--
作者：
M. Nakata;Tomo-Hiko Watanabe;H. Sugama;W. Horton
采用非线性回旋动力学Vlasov方法，对平板电子温度梯度（ETG）驱动的湍流中的涡旋结构和相关的热输运性质进行了全面的研究，旨在阐明从湍流态到相干态转变的物理机制.数值结果显示了三种不同类型的涡结构，相干的旋涡街道伴随着运输减少，湍流旋涡与稳定的运输，和一个带状流为主的状态，取决于平行压缩的相对大小的抗磁漂移。特别是，相干涡街的形成与弱平行压缩的情况下，即使线性ETG模式的最大增长率是相对较大的强生成的纬向流。采用截断流体模型对ETG湍流进行了调制不稳定性分析，研究了ETG湍流中纬向流的产生。
Vortex structures and related heat transport properties in slab electron temperature gradient (ETG) driven turbulence are comprehensively investigated by means of nonlinear gyrokinetic Vlasov simulations, with the aim of elucidating the underlying physical mechanisms of the transition from turbulent to coherent states. Numerical results show three different types of vortex structures, i.e., coherent vortex streets accompanied with the transport reduction, turbulent vortices with steady transport, and a zonal-flow-dominated state, depending on the relative magnitude of the parallel compression to the diamagnetic drift. In particular, the formation of coherent vortex streets is correlated with the strong generation of zonal flows for the cases with weak parallel compression, even though the maximum growth rate of linear ETG modes is relatively large. The zonal flow generation in the ETG turbulence is investigated by the modulational instability analysis with a truncated fluid model, where the parallel dynam...