講演情報
[21p-A302-13]Pressure Wave Formation of Atmospheric Pressure Plasma Jet by Optical Wave Microphone Measurement
〇THUZAR PHYO WAI1, MITSUGI FUMIAKI1 (1.Kumamoto University)
キーワード：
Plasma Jet
One of the most important observations on what plasma jets emit is pressure waves which have been focused on energic distribution of electric discharges in atmospheric pressure. Pressure waves can be detected by using some optical methods such as schlieren and shadowgraph that enable to visualize refractive index differences for phase objects. Those methods are useful to visualize the directivity and turbulence of gas flow in plasma jets, while they are not sensitive to detect very small refractive index changes such as pressure waves. In the previous studies, a unique optical technique called optical wave microphone technique had successfully detected shockwaves emitted a helium plasma jet was also successfully done at the downstream of the plasma jet in the frequency order of kilohertz. The rise timing of the pressure wave cannot be detected exactly because of the lack of frequency response of the microphone to higher frequency component by changing the distances in a set of electrodes. The intensity of the observed pressure wave is influenced by the irradiation distance and gas flow rate that influence in the compressibility of the helium/air mixture.