Optical fiber interferometer application for high electron density measurements on compact torus plasmas
Sen Zhang, Chen Chen, Tao Lan, Weixing Ding, G. Zhuang, Wenzhe Mao, Shijie Lan, Jie Wu, Hangqi Xu, Tijian Deng, Junfeng Zhu, Jiaren Wu, Yiming Zu, Defeng Kong, Shoubiao Zhang, Yuan Yao, Zian Wei, Zixi Liu, Haiyang Zhou, Hai Wang, Xiaohui Wen, A. D. Liu, Jinlin Xie, Hong Li, C. Xiao, Wandong Liu
Abstract
An optical fiber Mach–Zehnder interferometer at a wavelength of 1.55 µm has been developed for measurements of high electron density on compact torus (CT) plasmas with a high time resolution of 0.1 µs and high phase resolution of 6.4 × 10−4 rad. To improve density measurement accuracy, the phase noise of the interferometer has been investigated in detail and optimized. In the bench test, the interferometer was calibrated using a piezoelectric ceramic actuator with known stroke. Initial results on CT plasma show that the optical fiber interferometer provides reliable density measurements at two spatial locations and the bulk velocity of plasma can be determined by the method of time of flight.