Investigation of zonal flows by using the collective scattering measurement of density fluctuations
Investigation of zonal flows by using the collective scattering measurement of density fluctuations
复制标题
使用密度涨落的集体散射测量研究纬向流
DOI：
10.1088/0029-5515/55/9/093004
复制
发表时间：
2015
期刊：
影响因子：
3.3
通讯作者：
Li J. G.
中科院分区：
文献类型：
--
作者：
Shen H. G.;Yu Y.;Lan T.;Li Y. D.;Liu A. D.;Xie J. L.;Liu W. D.;Yu C. X.;Zhang W. Y.;Ti A.;Li J. G.
利用瞬时频率法（IFM）研究了核心等离子体区的极向Ũ E B r T旋转速度，并在HT-7托卡马克上用CO2激光集体散射诊断仪测量了密度波动。在模频率为10 ~ 20khz的极向速度波动中观察到相干模。识别为极向对称（m= 0）的测地线声模（GAM）纬向流，其模态频率与理论期望GAM频率一致。利用包络分析对密度波动进行了非线性相互作用研究。结果证实了高频密度波动中的包络调制仅来自于GAM的剪切作用。本文还讨论了IFM和包络分析的比较。
The poloidal Ũ E B r T rotation velocities in the core plasma region are studied using the instantaneous frequency method (IFM) with the density fluctuations measured by the CO2 laser collective scattering diagnostics on the HT-7 tokamak. A coherent mode is observed in the fluctuations of poloidal velocities with the mode frequency from 10 to 20 kHz. It is identified as geodesic acoustic mode (GAM) zonal flow with poloidal symmetry (m= 0) and its mode frequency coinciding with the theoretical expected GAM frequency. The nonlinear interactions are investigated by applying the envelope analysis on the density fluctuations. The results confirm that the envelope modulation in the high frequency density fluctuations only comes from the shearing by GAM. The comparison between IFM and envelope analysis is also discussed.