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

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; Ahdi Liu; Jinlin Xie; Hong Li; Wandong Liu; Chijin Xiao; Ge Zhuang

doi:10.1063/5.0212144

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

Rev Sci Instrum. 2024 Oct 1;95(10):103514. doi: 10.1063/5.0212144.

Authors

Tao Lan¹, Zeqi Bai¹, Han Zhang¹, Zhiling Mao¹, Weixing Ding¹, Jie Wu¹, Ke Wang¹, Xuan Sun¹, Min Wang¹, Wenzhe Mao¹, Sen Zhang¹, Qilong Dong¹, Yongkang Zhou¹, Chen Chen¹, Tianxiong Wang¹, Pengcheng Lu¹, Yuhua Huang¹, Zhengwei Wu¹, Jiaren Wu¹, Peng Deng¹, Zian Wei¹, Xiaohui Wen¹, Hai Wang¹, Chu Zhou¹, Ahdi Liu¹, Jinlin Xie¹, Hong Li¹, Wandong Liu¹, Chijin Xiao^{1

2}, Ge Zhuang¹

Affiliations

¹ Department of Plasma Physics and Fusion Engineering, University of Science and Technology of China, Hefei 230026, China.
² Plasma Physics Laboratory, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada.

PMID: 39392343
DOI: 10.1063/5.0212144

Abstract

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.