Time delay statistics modeling of megavolt self-triggered pre-ionized switch under nanosecond pulses

This paper establishes and validates a semi-quantitative calculation model for the breakdown time delay and jitter of a megavolt self-triggered pre-ionized switch under nanosecond pulses. The calculated error for the time delay ranges from 0.6% to 12.6%, and the observed variation trend in jitter is deemed reliable. The influence mechanisms of the breakdown time delay and jitter, as predicted by the model, align with experimental results. Notably, a jitter offset effect is identified in the pulsed breakdown process due to the time-varying electric field. The study predicts and confirms that the optimal breakdown time for the trigger gap under pulsed pre-ionization mode is ∼70% of the peak time of the input pulse and the gradient resistor should not exceed 4 kΩ under continuous pre-ionization mode to maintain the intensity of the switch leak current. This model is an extension of the Donaldson model, including the pre-ionization source with an inherent jitter and the formative time delay under nanosecond pulses. This framework may serve as a reference for analyzing time jitter statistics of other megavolt pulsed gas switches.