Expansion of Direct-Current Discharge Structure in Ambient Air Under Atmospheric Pressure

Direct-current atmospheric pressure plasma in a simple setup between two metallic electrodes is subject to disturbances which lead to discharge constriction on the electrodes. This paper presents a novel method to get rid of this plasma constriction, replacing the metallic electrode, in particular the anode, to a temperature variable resistive ceramic. It is shown that after ignition, the plasma tends to spread out circularly over the surface of the resistor electrode. This stands in contradiction to the lateral contraction phenomena of the plasma column on the metallic anode.