Electrical characterization of an atmospheric pressure Townsend discharge exposed to a conductive layer: an update of the equivalent circuit

Abstract We investigate how a dielectric barrier discharge is affected by a layer of iron nanoparticles deposited on top of one of the dielectrics. Specifically, an atmospheric pressure Townsend discharge is generated in pure nitrogen, and we find that when the Fe nanoparticle coating on the dielectric is conductive, it notably influences the dielectric capacitance. Due to the altered capacitance, an update to the equivalent circuit that is used to analyze the discharge is required. Employing the updated equivalent circuit, where the dielectric capacitance of the discharging fraction is replaced by the highest available dielectric capacitance, we show that the increased capacitance due to the conductive layer clearly affects the discharge characteristics, such as the current and deposited power. In addition, we observe a decrease in the discharge voltage caused by the iron nanoparticles, indicating that there may be surface effects enhancing the release of charges, enabling a discharge at lower voltages. This work offers additional insights into the mechanisms influencing dielectric barrier discharges, especially the effects of materials exposed to the plasma. Moreover, it enables a broader application and interpretation of the electrical characterization of DBDs, for example for an expanded discharge, which is crucial to understand the plasma properties.