Effects of the shielding cylinder and substrate on the characteristics of an argon radio-frequency atmospheric glow discharge plasma jet

Abstract

With unique features of low breakdown voltages, large and uniform discharge areas and high concentrations of chemically reactive species, radio-frequency, atmospheric-pressure glow discharge (rf APGD) plasma sources produced with bare-metallic electrodes have shown promising prospects in the field of materials processing. In this paper, the spatial distributions (i.e., the directly measured integrated axial distribution and the radial distribution by using the inverse Abel transform) of the emission intensities of the Ar I 696.5 nm line are studied for the argon rf APGD plasma jet under different operation conditions, including variations of the rf power input or the argon flow rate, the existence of the solid shielding cylinder or the substrate. The experimental results show that, with other parameters being unchanged, the emission intensities of the Ar I 696.5 nm line increase with increasing the rf power input or the argon flow rate; and the solid shielding cylinder has more significant influences on the characteristics of the plasma impinging jet by reducing the mass flow rate of the ambient air entrained into the plasma jet region than those for the cases without the existence of the substrate at the downstream of the plasma torch nozzle exit.