First results from the J-TEXT high-resolution three-wave polarimeter-interferometer.
First results from the J-TEXT high-resolution three-wave polarimeter-interferometer.
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DOI：
10.1063/1.4729674
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发表时间：
2012-06
期刊：
影响因子：
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通讯作者：
J. Chen;G. Zhuang;Z. J. Wang;L. Gao;Q. Li;W. Chen;D. Brower;W. Ding
中科院分区：
文献类型：
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作者：
J. Chen;G. Zhuang;Z. J. Wang;L. Gao;Q. Li;W. Chen;D. Brower;W. Ding
在J-TEXT托卡马克装置上实现了一个基于激光的三波远红外偏振干涉仪系统。偏振计通过测量两个共线、反向旋转的圆偏振激光束之间的相位差来确定法拉第效应。为J-TEXT设计的偏振干涉仪的第一个结果已经在最近的J-TEXT实验活动中获得。在50 kHz带宽下，实现了偏振测量和干涉测量的同时进行，相位分辨率可达0.1°。时间分辨率取决于激光器的频率偏移，为0.1 μs。利用一维抛物面光束扩展光学器件实现了45 cm（等离子体截面的80%）的连续空间测量。安装了三个初始测试弦，未来计划要求扩展到30个弦，弦间距为1.5 cm，为电子密度和电流密度分布的测量提供高空间分辨率。通过与氢氰酸（HCN）干涉仪的计算和数据的比较，证实了偏振和干涉测量的可靠性。在高的时间和相位分辨率下，观测到了与磁流体活动和磁流体循环有关的扰动。
A laser-based far-infrared polarimeter-interferometer system utilizing the three-wave technique has been implemented on the J-TEXT tokamak. The polarimeter determines the Faraday effect by measuring the phase difference between two collinear, counter-rotating, circularly polarized laser beams. The first results of the polarimeter-interferometer designed for J-TEXT have been obtained in the most recent J-TEXT experimental campaign. Simultaneous polarimetric and interferometric measurement is achieved, with phase resolution up to 0.1°, at bandwidth of 50 kHz. The temporal resolution, which is dependent on the laser's frequency offset, is ∼1 μs. Continual spatial measurement covering 45 cm (80% of the plasma cross-section) is realized by utilizing 1D parabolic beam expansion optics. Three initial test chords are installed and future plans call for expansion up to 30 chords with 1.5 cm chord spacing, providing high spatial resolution for measurement of electron density and current density profiles. Reliability of both polarimetric and interferometric measurement is confirmed by comparison with computation and data from a hydrocyanic acid (HCN) interferometer. With the high temporal and phase resolution, perturbations associated with the sawtooth cycle and MHD activity have been observed.