General evolution of discharge state with nitrogen content in atmospheric pressure helium/nitrogen dielectric barrier discharge

Atmospheric pressure dielectric barrier discharge (DBD) holds extensive application prospects in fields such as material processing, biomedicine, and energy conversion. Discharge stability plays a crucial role in achieving efficient, controllable, and reproducible plasma treatment. While the inevitable presence of impurity N2 in the working gas significantly influences discharge characteristics, the current understanding of N2 content on discharge stability remains insufficient. In this work, we systematically investigated the impact of N2 content on the temporal nonlinear behavior of atmospheric pressure He/N2 DBD using a one-dimensional fluid model. Our findings reveal a general characteristic of discharge evolution under different initial conditions: as the N2 content increases, the discharge initially develops into a chaotic state and then evolves into a symmetric single-period state through inverse period-doubling bifurcation. This evolution involves variations in electron backflow regions and the resulting differences in seed electron density between two consecutive applied voltage cycles. The present work provides an insight into the role of N2 content in modulating the temporal nonlinear dynamics of atmospheric pressure DBD, offering theoretical guidance for achieving stable discharge in plasma applications.