Measurement of electron and neutral particle densities using a two-color optical fiber interferometer

作者：Tao Lan, Zeqi Bai, Han Zhang, Zhiling Mao, Weixing Ding, Jie Wu, Ke Wang, Xuan Sun, Min Wang, Wenzhe Mao, Sen Zhang, Qilong Dong, Yongkang Zhou, Chen CHEN, Tianxiong Wang, Pengcheng Lu, Yuhua Huang, Zhengwei Wu, Jiaren Wu, Peng Deng, Zian Wei, Xiaohui Wen, Hai Wang, Chu Zhou, A. D. Liu, Jinlin Xie, Hong Li, Wandong Liu, C. Xiao, G. Zhuang · 发表于：Review of Scientific Instruments · 年份：2024 · DOI：10.1063/5.0212144 · 被引用次数：5 · 研究领域：Magnetic confinement fusion research、Plasma Diagnostics and Applications、Dust and Plasma Wave Phenomena

A two-color homodyne Mach-Zehnder optical fiber interferometer is developed for the measurement of electron and neutral particle densities in a high-density capsule θ-pinch device. The interferometer leverages the disparate contributions of distinct particles to the refractive index across two discrete wavelengths of 1310 and 1550 nm and incorporates the contributions of both electron and neutral particle densities to the phase shift in the plasma. The temporal evolutions of line-integrated electron and neutral argon densities are successfully measured by the interferometer. Comparing the electron density waveforms under various working gas pressures as well as the results obtained using the monochromatic and two-color measurements, it is inferred that the influence of neutral particle density can be neglected when measuring the electron density using a long-wavelength laser. Moreover, the maximum electron density is linearly correlated with the capacitor bank voltage for the θ-pinch device (5-9 kV). Overall, the proposed interferometer is capable of simultaneously measuring the electron and neutral particle densities.