Influence of He Gas Flow Rate on Optical Emission Characteristics in Atmospheric Dielectric-Barrier-Discharge Plasma Jet

We present here the analysis of the characteristics of a dielectric-barrier-discharge (DBD) plasma jet in open air using the optical emission spectroscopy (OES). The OES on oxygen emission is useful to estimate the presence of reactive excited O atoms. The O emission intensity is much higher near the quartz-tube outlet and abruptly decreases with distance from the quartz tube. Our experiments also show that the DBD plasma jet is quite sensitive to He gas flow rate (R_{He-gas flow}): increasing R_{He-gas flow} induces weak pulse discharge, resulting in decreasing O emission intensity.