1. Real-time processing system of a two-color CO2 laser interferometer for density feedback control in JT-60SA.
- Author
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Ohtani, Y., Sasao, H., Nakano, T., Fukumoto, M., Wakatsuki, T., Inoue, S., Kojima, S., Urano, H., and Yoshida, M.
- Abstract
A real-time processing system for the two-color CO2 laser interferometer on the JT-60SA has been developed for density feedback control. The system has a novel feature that can detect fringe jumps due to off-normal events, such as loss detection due to displacement of the beam axis and changes in the laser wavelengths. Because a phase change due to the JT-60SA plasma is smaller than π/2, corresponding to the line-integral electron density NL of ∼ 6 × 1 0 19 m−2 in a short interval of 500 ns, the threshold of the fringe jump detection is decided to be π/2. Hence, off-normal events can be detected from a fringe jump, leading to the abort of the real-time feedback control. In the density feedback control of the JT-60SA plasma, the system is employed as a density monitor, with NL being successfully controlled at 16.8% ± 6.6% lower than the reference. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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