Time-Resolved Observation of Plasma Jets Synchronized With Fibered Optical Wave Microphone Measurement

Our concern with plasma jets is the generation of pressure waves that influence the surface or the inside of targets. In this paper, the detection of pressure waves emitted from plasma jets was carried out using a fibered optical wave microphone, which works based on Fraunhofer diffraction for phase objects, with a synchronized high-speed camera observation of the dynamic behavior of plasma jets and their electrical properties. The electrode configuration of typical dielectric barrier discharge tubes was used in He gas flow. Effects of the amplitude and frequency of applied voltages and He gas flow rates on relationships among the irradiation of plasma jets, the generation of pressure waves, and current waveform were studied. Pressure waves were detectable by the fibered optical wave microphone, even though the irradiation of plasma jets from the glass tube was not observed with the high-speed camera. Frequency dependence on the generation of pressure waves was confirmed.