Electronegative microchannel guided streamer propagation for in-liquid spark breakdown applications

Applied Physics Letters, Volume 118, Issue 10, March 2021. One of the well-known challenging issues of in-liquid spark breakdown is electrode wear and wear-dependent deposit energy fluctuation, regardless of the electrode materials. This work suggests a method that can reduce the breakdown threshold by an order of magnitude and hence enhances the likelihood of breakdown, regardless of wear. Generally, the negative streamer propagates in a branching way; however, the present experiment indicates that the electronegative microchannel is converged with the streamer propagation and extends the breakdown gap distance between the electrodes. Subsequently, the breakdown-possible gap distance was extended by 14.3 times, leading to an enhancement of shockwave intensity by 33%. Such an extension of the breakdown conditions was achievable without any additional source energy input or changing the substance of dielectric electrodes. Thus, the results provide a favorable scheme for energy reduction in high-voltage systems, cost saving for electrode replacement, and enhancement of the propagating shock pressure.