Shock wave release behavior of a pulsed positive streamer discharge in water

We performed experimental observations to distinguish an individual shock front released by a pulsed positive streamer discharge in water. The step length between two adjacent shock wave events was measured and its dependence on water conductivity and applied voltage was investigated. We found that the step length between two adjacent shock wave events is ∼160 μm, independent of both water conductivity and applied voltage, within the range studied. Based on the bubble theory of electrical discharge in liquid, we concluded that the individual shock front is released by the electrical breakdown of a gaseous micro-segment near the head of a streamer filament in water. After launching a shock wave, the filament head pauses and waits for another gaseous micro-segment to form in front of it.