Measurement of density fluctuation propagation direction via the far-forward collective scattering diagnostic based on polarimeter-interferometer.
Measurement of density fluctuation propagation direction via the far-forward collective scattering diagnostic based on polarimeter-interferometer.
复制标题
基于旋光干涉仪的远前集体散射诊断测量密度涨落传播方向。
DOI：
10.1063/1.5038845
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发表时间：
2018
影响因子：
1.6
通讯作者：
Zhou C X
中科院分区：
文献类型：
--
作者：
Shi P;Qiu Q S;Zhuang G;Gao L;Zhou Y N;Zhou C X
在此之前，J-TEXT托卡马克装置上的17通道三波偏振干涉仪系统（POLARIS）已被用于测量电子密度涨落的远向前集体散射（FFCS）。最近，该系统已被用来测量密度波动的传播方向。在考虑激光探测光束通过等离子体后的折射后，光线追迹结果表明，POLARIS探测器可以接收到非对称的远场散射光束。因此，FFCS的外差探测可以通过分辨非对称散射谱来确定密度涨落的传播方向。实验上观察到外差散射谱由对称向非对称的转变，同时折射效应变强，证明了测量涨落传播方向的能力。此外，通过改变等离子体电位通过使用施加的正电极偏置，确定的外差散射谱的频率偏移的反转，确认的有效性的密度波动的方向歧视。
Previously, the 17-channel three-wave polarimeter-interferometer system (POLARIS) on the J-TEXT tokamak has been implemented to measure far-forward collective scattering (FFCS) from electron density fluctuations. Recently, this system has been exploited to measure the propagation direction of density fluctuation. After considering the refraction of the laser probe beam passing through plasma, the ray tracing result shows that the detector of POLARIS may receive asymmetric far-forward scattering beams. Thus, the heterodyne detection of FFCS is available to identify the propagation direction of density fluctuation by resolving the asymmetric scattering spectrum. Experimentally, the transform of the heterodyne scattering spectrum from symmetry to asymmetry has been observed, while the refraction effect becomes strong demonstrating the capacity of measuring the propagation direction of fluctuation. Furthermore, by changing the plasma potential through the use of an applied positive electrode biasing, the reverse of frequency shift for the heterodyne scattering spectrum is identified, confirming the validity of direction discrimination of density fluctuation.