Evolution of the Discharge Mode From Chaos to an Inverse Period-Doubling Bifurcation in an Atmospheric-Pressure He/N₂ Dielectric Barrier Discharge in Increasing Nitrogen Content

This work presents a numerical investigation on the evolution of the temporal nonlinear behavior in an atmospheric pressure He/N ₂ DBD with nitrogen content, based on a 1-D fluid model. A complete evolution pathway of the discharge mode with nitrogen content has been revealed. This pathway is in order of chaotic discharge, period-doubling discharge, and asymmetric single-period discharge, presenting the feature of an inverse period-doubling bifurcation and indicating that the chaos mode in a pure helium DBD can evolve into an asymmetric single-period discharge by adding N ₂ to He working gas. The evolution mechanism has been shown. The behavior of the seed electron density from cycle to cycle is the same as that of the discharge, thus correlating with the discharge mode. With increasing nitrogen content, the behavior of the electron backflow in the discharge from cycle to cycle evolves from nonuniformity to near uniformity, leading to a similar evolution behavior of the seed electrons. The increase in nitrogen content induces an increasingly strong minor discharge through Penning ionization, making the evolution of the electron backflow be similar to that of the seed electrons and thus producing the discharge mode evolution presented above. The surface charges are of a strong correlation with the evolution of the discharge mode because of their contribution to the seed electrons.