The Pulsed Negative Corona in Nitrogen with Different Needle-Plane Electrodes

Corona discharge is widely used in many fields, such as material modification and pollution controlling. However, the understanding of pulse mode in electropositive gas is not deeper enough. In this work, the negative DC corona discharge in nitrogen with needle-plane electrodes is studied. Discharge phenomena under different needle radii (0.05-0.28mm) and interelectrode distances (5-15mm) are explored. The discharge modes of nitrogen corona include Townsend mode, pulsed mode and glow mode, which are similar to corona modes in air. With the increasing of needle radius and interelectrode distance, the quantity of electric charge transferring in single pulse increases. Because there will be more secondary electrons emission when needle radius increases. With interelectrode distance increasing the electrical field will be more non-uniform and higher around needle tip. So that the ionization will be stronger leading to larger current.