Numerical study on mechanisms of period-doubling bifurcation in pulsed dielectric barrier discharges at atmospheric pressure

In this paper, the mechanisms of the period-doubling bifurcation in pulsed Dielectric Barrier Discharges (DBDs) are numerically investigated at atmospheric pressure. Under the given discharge conditions, the pulsed DBDs could maintain a normal period-1 (P1) state at relatively larger repetition frequencies over 40 kHz, by decreasing the repetition frequency, namely, keeping the duration of the power-on phase unchanged but increasing the duration of the power-off phase, the simulation shows that the discharge bifurcates into a period-2 (P2) state after a transient period of instability. Although the charged particles can diffuse to the surface of dielectric plates more fully at a lower repetition frequency, the large quantities of ions in the sheath region produced by the relatively larger discharge current that have not yet dissipated completely before the next discharge event are proposed to play an important role in the discharge bifurcation process, and the spatial profiles of the charged particle density, electric field, and space charge density in the sheath region before the discharge ignition are examined deeply to further explore the corresponding underpinning physics. The large density of residual ions in the sheath region with the enhanced electric field can weaken the subsequent discharge event and induce the discharge to enter the period-doubling state. Moreover, the computational data indicate that the discharge evolves into the period-4 (P4) and period-8 (P8) state when the repetition frequency approaches 30 and 26 kHz at the given discharge conditions. The simulation data can effectively facilitate the understanding of the temporal nonlinear behaviors in pulsed DBDs and propose ways to further control the plasma stability in applications.