Atmospheric pressure ejected plasma sources have been developed for processing arbitrary shaped objects. Plasma sources with
two coaxial electrodes are characterised experimentally by varying source design parameters such as discharge volume and
discharge gap distance under various operating conditions such as RF power, gas flow rate, and gas compositions. Using optical
emission spectroscopy (OES), gas temperatures and radical densities are qualitatively evaluated for flexible applications of the
source. Discharge characteristics as glow has been confirmed with voltage and current (V–I) probes. Based on these source
characteristics, specific design rules are presented for various applications such as polymer surface modification and metal surface
decontamination.