Mechanism Governing the Dependence of Temporal Nonlinear Behavior on the Gap Width in Atmospheric-Pressure Helium Dielectric Barrier Discharge-Role of Residual Charged Particles

In this article, the mechanism governing the dependence of temporal nonlinear behavior on the gap width in atmospheric-pressure helium dielectric barrier discharges has been numerically investigated based on a 1-D fluid model. The emphasis is placed on the role of residual charged particles. A complete evolution line of the discharge mode with the gap width has been given; it is in order of the symmetric single-period discharge, the asymmetric single-period discharge, the period-doubling discharge, and the chaotic discharge. In the asymmetric single-period discharges, the residual current coupling has been proposed for describing the effect of the residual positive column on the discharge, which dominates the asymmetry level of the asymmetric single-period discharge. The correlation of the residual current coupling with the seed electrons for the discharge in the positive half-cycle of the applied voltage has been revealed. This correlation indicates that the residual current coupling governs the evolution of the discharge mode with the gap width. Before it evolves into the chaos, the discharge will always first bifurcate from a symmetric single-period discharge into an asymmetric single-period discharge because an asymmetric discharge is governed mainly by the seed electrons after the residual electron peak which strongly correlates with a very weak discharge occurred in the negative half-cycle of the applied voltage.