Metastable Oxygen Formation in an Atmospheric Pressure Plasma Jet

Presented here are detailed measurements of an argon atmospheric pressure plasma jet producing metastable oxygen through the (O(¹S)-O(¹D)) transition. The emission at 557 nm, which is also referred to as the “auroral green” line, is observed regardless of electrode design, and various operating parameters such as applied voltage, gas flow and electrode gap. The plasma jet is characterized in detail using optical emission spectroscopy and analysis of electrical diagnostics. The intensity of oxygen and other reactive species are monitored with a high resolution spectrometer and CCD camera. The temporal behavior of the jet is monitored with a fast imaging CMOS camera. We also present analysis of the mean electron energy, electron density, and gas temperature. The stable behavior of the jet provides a large surface area for plasma treatment. Lastly, we present evidence of the plasma jet’s ability for industrial applications such as wastewater treatment.