Numerical Simulation of Multi-Peak Discharge and Its Radial Structures in Atmospheric Pressure Helium Dielectric Barrier Discharges

Abstract

Recent years have witnessed tremendous development of atmospheric pressure dielectric barrier discharges (DBDs) in theoretical studies as well as applications. Typically, DBD manifests itself as a “single peak” discharge, in which only one current pulse exists in every half cycle of the applied voltage 1. However, in certain conditions, multi-peak discharge, in which two or more current pulses exist in one voltage half cycle, can be observed 1, while its mechanisms are far from being understood. In this paper, the atmospheric pressure helium DBDs with multiple current peaks are investigated by a self-consistent two-dimensional fluid model. It is found that different current peaks occurs in different radial positions of the discharge gap, and the distribution of discharge columns conform to the characteristics of activation-inhibition effect 2. It is the concentration of surface charge and residual space charge that lead to the enhancement of local electric field in a certain radial position of the gap, thus initiating the breakdown. When a certain discharge column is formed, the breakdown process in the nearby region is inhibited, while the process in the other regions can be activated and another breakdown is induced. As a result, the multi-peak discharge is generated. This study provides a more insightful understanding on the mechanisms of multi-peak and filamentary discharges in DBDs.