Effect of dielectric aging on the behavior of a surface nanosecond pulsed dielectric barrier discharge

In this study, surface Dielectric Barrier Discharge (DBD) actuators powered by a nanosecond pulsed high voltage are investigated. The goal is to experimentally analyze the effect of dielectric aging on the electrical behavior of the discharge and the surface plasma morphology. The used actuator is made of two conducting electrodes separated by a thin dielectric made of polyimide and arranged asymmetrically. The active electrode is connected to a nanosecond pulsed high voltage power supply and the second electrode is grounded and encapsulated inside a dielectric material. The actuator is aged by using the surface DBD supplied continuously during 15 minutes with a voltage pulse of + 10 kV at a frequency of 1 kHz and a pulse width of 250 ns. The experimental results show the existence of two discharges during both rising and falling periods of the voltage for both virgin and aged actuators. After aging, a third discharge current component is observed during the voltage plateau due to the ignition of additional discharges, which enhance the energy per pulse. ICCD camera images indicate that the plasma layer extends further on the dielectric surface in the case of aged actuators. In addition, large and non-localized filaments appear during the voltage plateau after aging due to the non-homogenous positive space charge distribution that intensifies the electric filed locally.