Discussion on the influences of townsend ionization coefficient α and secondary electron emission coefficient γ on the characteristics of DBD

Abstract

Dielectric barrier discharge (DBD) has drawn great attentions in recent years, and the discharge physic is one of the research focuses. In this paper, both Townsend ionization coefficient α and secondary electron emission coefficient γ (SEEC) in DBD are discussed. The value and partial derivative of α in pure helium are compared with that of argon theoretically, which is related to the breakdown voltage and discharge channel radius. The changes of discharge channel radius under different electrical field is obtained, and the high nonlinear relationship between α and electrical field (∂(α)/∂(E)) is believed to be the main reason for discharge contraction1. Therefore, we mix a little NH3 in argon to make the α different from that of pure argon and work in the region where the ∂(α/∂(E) is relatively low. In this way, the uniform discharge, similar with He-DBD, can be obtained in the Ar/NH3 DBD.