In search of zonal flows by using direct density fluctuation measurements
In search of zonal flows by using direct density fluctuation measurements
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DOI：
10.1088/0741-3335/49/10/002
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发表时间：
2007-10
影响因子：
2.2
通讯作者：
Y. Nagashima;K. Itoh;S. Itoh;A. Fujisawa;Masatoshi Yagi;Katsumichi Hoshino;K. Shinohara;A. Ejiri;Y. Takase;T. Ido;K. Uehara;Y. Miura
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文献类型：
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作者：
Y. Nagashima;K. Itoh;S. Itoh;A. Fujisawa;Masatoshi Yagi;Katsumichi Hoshino;K. Shinohara;A. Ejiri;Y. Takase;T. Ido;K. Uehara;Y. Miura
本文提出了一种利用密度脉动直接测量研究纬向流的方法。当环境漂移波湍流被纬向流调制时（即在漂移波纬向流系统中），环境密度波动的包络在纬向流频率附近具有谱峰。在JFT-2 M托卡马克边缘等离子体测量的环境密度起伏包络中，观测到了测地声学模（GAM）频率处的谱峰。环境密度涨落与其GAM频率包络之间存在显著的交叉双相干。这一结果表明，我们可以测量的GAM只使用密度涨落数据。该方法为利用微波反射等密度涨落诊断技术研究燃烧堆芯等离子体中的纬向流提供了可能。
A method for zonal flow study by using direct density fluctuation measurements is proposed. When ambient drift-wave turbulence is modulated by zonal flows (i.e. in the drift-wave-zonal flow systems), an envelope of the ambient density fluctuations has spectral peaks around zonal flow frequencies. A spectral peak at the geodesic acoustic mode (GAM) frequency is observed in the envelope of the ambient density fluctuations measured in edge plasma of the JFT-2M tokamak. The significant cross-bicoherence is also found between the ambient density fluctuations and its envelope in the GAM frequency. This result demonstrates that we can measure the GAM only by using density fluctuation data. This method provides a possibility of zonal flow research in burning core plasma by density fluctuation diagnostics such as microwave reflectometry.