Characteristics of atmospheric-pressure non-thermal N2 and N2/O2 gas mixture plasma jet

An atmospheric-pressure non-thermal plasma jet driven by high frequency alternating current and operating on N2 and N2/O2 gas mixture is investigated. The plasma jet can reach 55 mm in length at a gas flow rate of 2500 l/h. The gas temperature at a distance of 4 mm from the nozzle is close to room temperature. Optical emission spectroscopy is employed to investigate the important plasma parameters such as the excited species, rotational temperature, vibrational temperature, and excitation temperature under different discharge conditions. The results show that the plasma source operates under non-equilibrium conditions. The absolute irradiance intensity of the vibrational band N2(C-B) in the active region is measured. Taking into account the irradiance intensity of N2(C-B,0-0) and N2(B-X,0-0) as well as measured current, the electron density, which is determined by considering direct and step-wise electron impact excitation of nitrogen emission, reaches a maximum value of 5.6 × 1020/m3.