Influence of pre-ionization parameters on multi-channel discharge characteristics of field-distortion switch gaps

The UV pre-ionized field-distortion gas switch has advantages such as low jitter, low trigger threshold, low inductance, and long lifetime, making it highly suitable for widespread use in pulsed power devices. To investigate the influence of key pre-ionization parameters on the multi-channel discharge characteristics of field-distortion switch gaps, an experimental method is proposed to study the effect of individual pre-ionization parameters on a single switch gap. The effects of pre-ionization injection time, pre-ionization current amplitude, and pre-ionization duration on the number of discharge channels in the trigger gap and overvoltage gap are examined. For the trigger gap, the number of discharge channels increases as the pre-ionization injection time is advanced, and it also increases with higher pre-ionization current amplitude and longer pre-ionization duration. When there is no pre-ionization, the trigger gap typically exhibits only a single discharge channel. For the overvoltage gap, due to ultraviolet radiation from the discharge in the trigger gap, multi-channel discharge can still occur without pre-ionization current. The number of discharge channels increases with higher pre-ionization current but is unaffected by pre-ionization applied before the breakdown of the trigger gap. With the increase in the pre-ionization duration after the breakdown of the trigger gap, the number of discharge channels increases and eventually tends to saturation. Based on the quantitative experimental results, a new switch with more than three discharge channels in both gaps is developed, and the switch inductance and electrode erosion loss are reduced obviously.