Experimental investigation of an atmospheric pressure DBD under bi-polar pulsed High Voltage excitation

This work presents a primary experimental study of a custom-made coaxial DBD reactor driven by a bipolar pulsed High Voltage supply. The reactor is fed by nitrogen or air at atmospheric pressure conditions and uses a dielectric coating on the HV electrode. The High Voltage generator delivers a ¿pulse-like¿ bipolar signal in the 10-50 kHz frequency range. This set-up has been conceived for surface treatment applications in afterglow conditions. Electrical and optical diagnostics are employed for the investigation of the nitrogen and air DBD while varying the frequency of the HV bipolar signal and the maximum applied voltage. Current and voltage oscillogrammes are used in order to derive the mean plasma power injected in the gap. Photomultiplier scans reveal the discharge´s filamentary character whereas Optical Emission Spectroscopy (OES) shows the excited species present in such conditions. Comparisons between electrical and OES results show a correlation between the mean plasma power and the production of active species.