使用双色零差光纤干涉仪对线积分等离子体电子密度进行长时间测量。

Long-time measurements of line-integrated plasma electron density using a two-color homodyne optical fiber interferometer.

作者信息

Lan Tao, Zhang Sen, Ding Weixing, Zhuang Ge, Wu Zhengwei, Mao Wenzhe, Chen Chen, Lan Shijie, Xu Hangqi, Deng Tijian, Zhu Junfeng, Wu Jiaren, Zu Yiming, Kong Defeng, Zhang Shoubiao, Yao Yuan, Yuan Peng, Wei Zian, Zhou Haiyang, Wang Hai, Wen Xiaohui, Wu Jie, Zhou Chu, Liu Ahdi, Xie Jinlin, Li Hong, Xiao Chijin, Liu Wandong

机构信息

Department of Plasma Physics and Fusion Engineering, University of Science and Technology of China, Hefei 230026, China.

Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China.

出版信息

Rev Sci Instrum. 2021 Sep 1;92(9):093506. doi: 10.1063/5.0055570.

DOI:10.1063/5.0055570

PMID:34598546

Abstract

A two-color homodyne Mach-Zehnder (M-Z) optical fiber interferometer with wavelengths of 1.55 and 1.31 µm was developed for long-time measurement of line-integrated plasma electron density. A novel phase difference demodulation algorithm based on a single 3 × 3 optical coupler was implemented in a two-color optical fiber interferometer scheme for the first time. Our laboratory tests showed that this new optical fiber interferometer could determine the phase shift due to the low-frequency ambient vibration and could maintain high phase resolution measurement. The resolution of the new interferometer was less than 0.04 rad in 1000 s, corresponding to a line-averaged electron density of less than 1.0 × 10 m. Actual plasma discharge experiments performed on KTX-CTI, which is a new compact torus injector (CTI) constructed at the Keda Torus eXperiment (KTX), showed that this interferometer has excellent several-second stability.

摘要

为了长时间测量线积分等离子体电子密度，研制了一种波长为1.55和1.31μm的双色零差马赫-曾德尔（M-Z）光纤干涉仪。一种基于单个3×3光耦合器的新型相位差解调算法首次应用于双色光纤干涉仪方案中。我们的实验室测试表明，这种新型光纤干涉仪能够确定由于低频环境振动引起的相移，并能保持高相位分辨率测量。新干涉仪在1000秒内的分辨率小于0.04弧度，对应于线平均电子密度小于1.0×10米。在科达托勒斯实验（KTX）中建造的新型紧凑型托卡马克注入器（CTI）——KTX-CTI上进行的实际等离子体放电实验表明，该干涉仪具有出色的数秒稳定性。