Effect of Prebreakdown Time on Shock Wave Generation Characteristics of Underwater Plasma Sound Source

Acoustic array bunching is an effective method to realize the directional radiation of underwater plasma sound source (UPSS). The prebreakdown time is one of the decisive factors for the performance of acoustic array bunching. The working characteristics of the underwater plasma sound source and the prebreakdown process of underwater plasma arc discharge are deeply analyzed. The precondition of plasma sound source array bunching is given by analyzing the waveforms of electrical signals and acoustic signals. Through the experiments of arc discharge based on different aqueous solutions, a feasible scheme of underwater plasma sound source array bunching in salt water is proposed. Through the arc discharge experiments based on different system discharge parameters, the variation of prebreakdown time under the influence of different charging voltage, conductivity, and other parameters was studied. The experimental results show that the prebreakdown time decreases with the increase of charging voltage and conductivity. At the same time, the discharge current increases, the oscillation time decreases, and the energy injection rate on the electrode accelerates. The research results are helpful to understand the prebreakdown mechanism of plasma sound source and optimize the underwater plasma sound source array bunching scheme and the acoustic shock wave waveform.