Measurement of Radial Hydrogen-Deuterium Ratio in EAST by Charge Exchange Recombination Spectroscopy

doi:10.3969/j.issn.1007-5461.2025.05.003

Abstract

Abstract: In response to the significance of hydrogen isotope ratio measurement in fusion research, the paper investigates the measurement of the density ratio of hydrogen (H) to deuterium (D) in the core plasma of EAST superconducting tokamak using the main ion charge exchange recombination spectroscopic diagnosis (MICER) system. In experiment, the neutral beam injection (NBI) modulation method is employed to effectively subtract the plasma edge D (H) radiation background from the MICER signal. During the experimental data processing stage, a eight-Gaussian fitting approach combined with Zeeman effect analysis is utilized to separate the charge exchange emission lines of Hα and Dα. The eightGaussian fitting assumes that the main ion temperature and velocity are the same as those of carbon ions, utilizes the plasma rotation velocity as the Doppler frequency shift velocity, and estimates the broadening parameters of Hα and Dα emission spectrum based on the broadening of the carbon charges exchange spectrum. As a result, the number of free parameters of Gaussian fitting is reduced from 12 to 4. The spectral line fitting method successfully distinguishes the radiation lines of thermal Hα from thermal Dα, thus enabling the measurement of the density ratio of hydrogen (H) to deuterium (D) in the plasma core.

Key words: plasma physics, hydrogen-deuterium ratio in core plasma, spectroscopic diagnostics, Zeeman effect, Gaussian fitting

CLC Number:

SHI Chang, , HUANG Juan, GAO Wei , SUN Yanxu, , WANG Shusong , WANG Xihui , . Measurement of Radial Hydrogen-Deuterium Ratio in EAST by Charge Exchange Recombination Spectroscopy[J]. Chinese Journal of Quantum Electronics, 2025, 42(5): 611-619.

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