Development of a triple-path, lowinductance, 0.5 MA, low-inductance, lowvoltage spark gap switch

• Published in: 2024 IEEE International Conference on Plasma Science (ICOPS) p. 1
• Main Authors: Yuan, W., Shen, Y., Thio, Y.C. F., Li, G., Wu, C., Hao, C., Zhang, C., Zhou, Y., Liang, F.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 16-06-2024
• Subjects: Jitter; Plasmas; Reproducibility of results; Spark gaps; Stability analysis; Switches; Time measurement
• ISSN: 2576-7208
• DOI: 10.1109/ICOPS58192.2024.10626742

We report on the development and testing of a triple-path, low-inductance, low-voltage, high-current, fielddistortion spark gap switch, as one of the key technologies in developing the next-generation coaxial plasma gun for plasma jet driven magneto-inertial fusion (PJMIF). The chamber of the spark gap switch has been designed to harbor three completely isolated, parallel electrical paths to achieve improved synchronization and low inductance. The idea is that if one of the switches triggers earlier, its ultraviolet radiation would help to trigger the other two switches. The mechanical design of the switch has been verified by FEM simulations, and the modular design of the switch significantly increases the efficiency of the testing by reducing the installation time. Paschen breakdown curve of the switch has been measured for Ar with a main gap spacing of 6 mm and gas pressure ranging from 0.1 BarG to 2.5 BarG, in an effort to determine the optimized operating parameters for the switch. The delay time and jitter of the spark gap switch have been measured on a dedicated switch test stand as well as in the single-trigger plasma-gunfiring experiments at operating voltages as high as 6 kV and peak currents as high as 900 kA, with a trigger voltage of 17 kV. The spark gap switches have demonstrated high stability and reproducibility in these experiments, with a jitter less than 200 ns.