Spectroscopic investigations of microwave microplasmas in various gases at atmospheric pressure

In this paper results of the experimental investigations of a coaxial microwave (2.45 GHz) microplasma source (MMS) with graphite or tungsten inner conductor operated in Ar, N2 and Ar/C2H2 mixture at atmospheric pressure are presented. The microwave power absorbed by the microplasmas and the intensity of UV-C emission from the microplasmas were measured. Using optical emission spectroscopy, the electron number density in Ar microplasma, and rotational and vibrational temperatures in N2 and Ar/C2H2 microplasmas were determined. All experiments were performed with a gas flow rate from 0.3 to 8 l/min and absorbed microwave power from 5 to 300 W. The simplicity of the MMS, stability of its operation with atmospheric pressure gases, and parameters of the microplasmas allow concluding that the MMS can be used in various applications.