Design and Characterization Study of a Pin-to-Pin Atmospheric Pressure Cold Plasma Jet System

This study presents an atmospheric-pressure air plasma jet system that utilizes two tungsten needle electrodes positioned diametrically opposite each other on the outer diameter of a cylindrical glass tube through which air is jetted. The electrodes were powered by a negative direct-current voltage source of 30 kV. The effects of electrode distance (9.6-13.6 mm), ballast resistance (5-20 kΩ) and electrode diameter (0.1-1.16 mm) on the discharge current and voltage (I-V) characteristics were inspected. The experimental results showed that increasing the electrode gap reduced the discharge current, while decreasing the electrode diameter increased it. The ballast resistor adjusts the voltage threshold between the corona, glow, and arc discharge systems. An optimal set of operational variables was identified to maximize discharge stability and plasma performance, where the investigation defined a power-law relationship between current and voltage, which is sensitive to the geometric and electrical parameters of the system. The study offers valuable highlights for the pin-to-pin plasma jet system, which could play an important role in plasma sterilization.