Imaging and Optical Emission Spectroscopy of Surface Dielectric Barrier Discharge (SDBD) Plasma Generated Using Reactors with Planar and Cylindrical Electrodes

We characterized non-thermal plasma generated in two types of Surface Dielectric Barrier Discharge (SDBD) reactors, one with a planar and the other with a cylindrical electrode. Plasma was examined using the time-resolved imaging and Optical Emission Spectroscopy (OES) methods. We observed that the cylindrical electrode suppresses plasma formation during both discharge modes: positive streamers and pseudo-Trichel microdischarges. The propagation velocity of the plasma front was estimated to be in the range 12–15 m/s, regardless of the discharge mode and electrode type. Spectral analysis showed that the plasma emission spectrum consisted mainly of the first and second positive nitrogen bands. Using Specair software, we calculated the plasma thermodynamic parameters and found that, despite morphological differences, the plasma generated in both reactors had similar thermodynamic properties. Finally, we discussed the temporal evolution of the discharge and attributed the plasma suppression caused by the cylindrical electrode to the characteristic uniformity of the electric field around and along this electrode.