Acoustic characterization of atmospheric-pressure dielectric barrier discharge plasma jets

In this work, we report the acoustic measurements performed on an atmospheric-pressure plasma jet (APPJ) ignited at various electrical conditions, and attempt to describe the origin of plasma-generated sound waves. The working principle of the APPJ source used for this investigation was based on a DC-pulsed dielectric barrier discharge in a helium flow. Our results indicated that the sound is generated in the plasma core in a glass tube between two cylindrical electrodes, rather than in the plasma jet that extends into the open atmosphere. We also explored the electrical conditions at which the sound level is below 85 dBA; that is, still within the safe level recommended by the National Institute for Occupational Safety and Health. Therefore, our findings can be used to advance our basic and applicable knowledge of APPJs.