Breakdown voltage scaling relation of isolated gas bubbles in liquid water

Atmospheric pressure plasma discharges have been investigated as a means to purify contaminated water, as these discharges efficiently produce a variety of highly reactive species¹. While much investigation has involved electrode-drive plasma initiation, the use of an electrode-less set up is attractive as it avoids electrode contamination. However, the breakdown of isolated bubbles in liquid water is still poorly understood. Fundamental breakdown relation may be investigated by determining the applied breakdown voltage necessary to produce plasma in bubbles of various pd, typically by changing the bubble size. Preliminary studies have seen a Paschen-like breakdown curve for isolated bubbles of various sizes²; this study examines the breakdown behavior for a parallel plate electrode set up, including time evolution of the discharge dynamics.