Spectral characteristics of zonal flows in the edge plasmas of the HT-7 tokamak
Spectral characteristics of zonal flows in the edge plasmas of the HT-7 tokamak
复制标题
DOI：
10.1088/0741-3335/52/8/085004
复制
发表时间：
2010-08
影响因子：
2.2
通讯作者：
A. Liu;T. Lan;C X Yu;W. Zhang;H. Zhao;D. Kong;J. Chang;B. Wan
中科院分区：
文献类型：
--
作者：
A. Liu;T. Lan;C X Yu;W. Zhang;H. Zhao;D. Kong;J. Chang;B. Wan
利用两点相关技术和双谱分析方法，对HT-7托卡马克上几个朗缪尔探针阵列测量的浮位起伏进行了研究，得到了包括测地线声学模（GAM）和零/低频纬向流（LFZF）在内的纬向流的谱特征。计算了这两种模式的三维波数和频谱。径向波数谱表明，LFZF包既向外传播又向内传播，而GAM包主要向外传播。在两相流中观察到了纬向流与环境湍流之间的非线性耦合，而在GAM频率下的双相干比在LFZF频率下的双相干大得多。报道了一种频率高于GAM的模态，这种模态也可能以类似于纬向流的方式由环境湍流产生。
The spectral characteristics of zonal flows, including both the geodesic acoustic mode (GAM) and the zero/low frequency zonal flow (LFZF), are investigated by applying the two-point correlation technique and bispectral analysis to the floating potential fluctuations measured by several Langmuir probe arrays on the HT-7 tokamak. The three-dimensional wavenumber and frequency spectra for the two modes have been estimated. The radial wavenumber spectra show that the LFZF packages propagate both outward and inward while the GAM packages propagate outward mostly. Nonlinear couplings betweeen zonal flows and ambient turbulence are observed in the biphase while the bicoherence at the GAM frequency is much larger than that at the LFZF frequency. A kind of mode with frequencies higher than that of GAM, which may also be generated from the ambient turbulence in a similar way as the zonal flows, is reported.