Formation of stable direct current microhollow cathode discharge by venturi gas flow system for remote plasma source in atmosphere

We introduce a microhollow cathode configuration with venturi gas flow to ambient air in order to obtain glow discharge at atmospheric pressure. Stable microhollow cathode discharge was formed in a 200 μm diameter at 9 mA and the optimum value of gas velocity×diameter for hollow cathode effect was obtained in our system. In order to confirm hollow cathode effect, we measured the enhancement of EN strength for 200 μm (0.31 m2 s) and 500 μm (0.78 m2 s) air discharge at 8 mA under the velocity of 156 ms. As a result, an increase of 46.7% in EN strength of the discharge of 200 μm hole was obtained compare to that of 500 μm.