Abstract:
Background Water-dielectric self-breakdown switches are critical components in pulsed power devices such as the 10 MA facility. The plate-sphere electrode structure is specifically designed to achieve simultaneous multi-channel discharge, which is essential for minimizing switch inductance and reducing timing jitter.
Purpose This study investigates the factors affecting multi-channel formation in a water-dielectric, three-electrode plate-sphere self-breakdown switch operating at 3 MV, with the aim of validating the theoretical formation criterion.
Methods Theoretical analysis was conducted based on the specific parameters of the switch structure, focusing on key temporal characteristics influencing discharge behavior. Experimental validation was performed at the nominal breakdown voltage of 3 MV, utilizing diagnostic techniques to observe the development of discharge arcs across all electrode pairs.
Results The calculated characteristic value for multi-channel formation was determined to be 8.6 ns, exceeding twice the measured switch jitter time of 3 ns, thereby satisfying the theoretical criterion. Observations confirmed that discharge arcs initiated nearly synchronously at the three sphere electrodes and propagated toward the plate electrodes, with complete multi-channel formation achieved within approximately 30 ns.
Conclusions The study validates the criterion for multi-channel discharge in the plate-sphere switch structure. The design effectively enables simultaneous formation of multiple discharge channels within tens of nanoseconds, meeting essential requirements for high-performance pulsed power devices and contributing to improved operational stability.
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