Study on characteristics of acoustic signals generated by different DC discharge modes

Acoustic signals contain rich discharge information. In this study, the acoustic signal characteristics of transient glow, spark, and glow discharges generated through DC pin–pin discharge were investigated. The signals were analyzed in the time, frequency, and time–frequency domains, and the correlation between the electric and the acoustic signal was studied statistically. The results show that glow discharge does not produce measurable sound signals. For the other modes, with a decrease in the discharge gap, the amplitude of the acoustic signal increases sharply with mode transformation, the short-time average energy becomes higher, and the frequency components are more abundant. Meanwhile, the current pulse and sound pressure pulse have a one-to-one relationship in the transient glow and spark regimes, and they are positively correlated in amplitude. A brief theoretical analysis of the mechanism of plasma sound and the trends of signals in different modes is presented. Essentially, the change in the discharge energy is closely related to the sound generation of the plasma.