Chen J, Gao L, Zhuang G, Wang Z J, Gentle K W
Institute of Nuclear Fusion and Plasma Physics, College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
Rev Sci Instrum. 2010 Oct;81(10):10D502. doi: 10.1063/1.3464269.
A multichannel three-wave far-infrared polarimeter-interferometer will be constructed on the J-TEXT tokamak (R=1.05 m, a=0.27 m, B(T)≤3 T, and I(P)≤350 kA) for current density profile and electron density profile measurements. The system will adopt the three-wave polarimeter configuration which was first introduced on RTP. Three 432.5 μm HCOOH lasers pumped by three CO(2) lasers separately will be adopted, which could generate high output power, nearly 50 mW at each cavity. Two of them will be counter-rotating circularly polarized to probe the Faraday angle, while the third laser will be used as a local oscillator to get the phase shift caused by electron density. Excellent port access (600×76 mm(2)) and high laser power would promise a profile measurement across the whole plasma section with good signal quality. A high-speed digital phase comparator with a few (∼2) μs temporal resolution will be developed, so that fast changes of current or density profile could be measured. Six channels will be installed in the first stage.
将在J-TEXT托卡马克装置（R = 1.05米，a = 0.27米，B(T)≤3特斯拉，I(P)≤350千安）上构建一台多通道三波远红外偏振计-干涉仪，用于测量电流密度分布和电子密度分布。该系统将采用首次在RTP上引入的三波偏振计配置。将采用由三台CO(2)激光器分别泵浦的三台432.5微米的HCOOH激光器，每台腔体能产生近50毫瓦的高输出功率。其中两台将反向旋转圆偏振以探测法拉第角，而第三台激光器将用作本地振荡器以获取由电子密度引起的相移。良好的端口接入（600×76毫米(2)）和高激光功率将保证在整个等离子体截面进行分布测量时具有良好的信号质量。将开发一台具有约2微秒时间分辨率的高速数字相位比较器，以便能够测量电流或密度分布的快速变化。第一阶段将安装六个通道。
