Droplet Striations Formed in a 900-MHz Microwave Argon Atmospheric-Pressure Plasma Jet

Unique striations were observed in the formation of 900-MHz microwave argon atmospheric-pressure plasma jet in air. The striated patterns are easily observed even with the naked eyes at a flow rate of above 3 slm and an input power of below 3 W. Moreover, the striated patterns, which were associated with shortening in the plasma jet length, are obtained by adding less than 1 vol.% of O
₂
gas to Ar.