Spatially resolved emission spectroscopic investigation of microwave-induced reactive low-power plasma jets

A microwave-induced Ar/SF6 plasma jet is characterized by means of optical emission spectroscopy. Rotational temperatures from unresolved N2 bands and excitation temperatures from Fe lines as well as electron densities (Hβ Stark broadening) have been estimated along the plasma jet axis using a side-on configuration. The SF6 gas flow rate and chamber pressure were varied from 10 to 250 sccm and 20 to 500 mbar, respectively. Three characteristic jet regions have been observed: the plasma ignition zone, followed by the gas mixing zone and a relaxing zone.