Spatio-temporal dynamics of turbulence trapped in geodesic acoustic modes
Spatio-temporal dynamics of turbulence trapped in geodesic acoustic modes
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DOI：
10.1063/1.5008541
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发表时间：
2018-01
影响因子：
2.2
通讯作者：
M. Sasaki;Tatsuya Kobayashi;K. Itoh;N. Kasuya;Y. Kosuga;A. Fujisawa;S. Itoh
中科院分区：
文献类型：
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作者：
M. Sasaki;Tatsuya Kobayashi;K. Itoh;N. Kasuya;Y. Kosuga;A. Fujisawa;S. Itoh
研究了测地声学模（GAM）相互作用下湍流的时空动力学，重点研究了湍流的相空间结构，其中相空间由实空间和波数空间组成.基于波动动力学框架，数值求解了气溶胶与湍流的耦合方程。得到了被GAM速度场捕获的湍流。由于捕获效应，湍流强度在GAM速度的二阶导数（GAM的曲率）为负的地方增加。而在正曲率区，湍流得到抑制。由于被捕获的湍流与GAM一起传播，因此这种关系在空间和时间上都是持续的。将波数谱中的湍流动力学转化为频率谱的演化，并将模拟结果与JFT-2 M托卡马克装置的实验观测结果进行了比较，得到了相似的结果。湍流捕获效应
The spatio-temporal dynamics of turbulence with the interaction of geodesic acoustic modes (GAMs) are investigated, focusing on the phase-space structure of turbulence, where the phase-space consists of real-space and wavenumber-space. Based on the wave-kinetic framework, the coupling equation between the GAM and the turbulence is numerically solved. The turbulence trapped by the GAM velocity field is obtained. Due to the trapping effect, the turbulence intensity increases where the second derivative of the GAM velocity (curvature of the GAM) is negative. While, in the positive-curvature region, the turbulence is suppressed. Since the trapped turbulence propagates with the GAMs, this relationship is sustained spatially and temporally. The dynamics of the turbulence in the wavenumber spectrum are converted in the evolution of the frequency spectrum, and the simulation result is compared with the experimental observation in JFT-2M tokamak, where the similar patterns are obtained. The turbulence trapping eff...