Experimental study of an atmospheric pressure DBD under unipolar pulsed HV excitation

This work presents a primary experimental study of a custom-made coaxial DBD reactor driven by a positive pulsed high voltage supply. The reactor is fed by N₂ or Air at atmospheric pressure and uses ceramic coatings as barriers. The high voltage generator delivers square pulses of variable rise/fall time, frequency, amplitude and pulse duration. Current oscillogrammes reveal the occurrence of two discharges during the HV pulse application: a primary one occurring at the rising part or the plateau of the applied voltage and a secondary (inverse) discharge taking place in the falling part of the applied HV signal. In these conditions short duration and high amplitude discharge current pulses were recorded, yielding instant plasma power peak values in the 50 kW range. Then, a parametric analysis of the discharge is made while varying the HV signal´s characteristics, showing the importance of the rise/fall time of the HV applied voltage for the unipolar DBD operation mode.