Mechanisms of low-frequency dielectric barrier discharge (DBD) plasma driven by unipolar pulses and bipolar pulses

In this study, experimental results presenting the development of Dielectric Barrier Discharge (DBD) powered by bipolar and unipolar pulses are compared. The experimental results showed that discharge current peaks in the case of DBD driven by repetitive unipolar pulses were about three times lower than those in the case of DBD driven by bipolar pulses. It is well known that if DBD is driven by bipolar pulses, the effect of surface charge on dielectric layers from the preceding discharge helps to ignite consecutive discharges at the same locations where the previous discharges already struck. In contrast, in the case of DBD generated by using the low-frequency unipolar pulses, the consecutive DBDs just could be initiated after the system erases part of the prehistory effect of surface charge deposition on dielectric layers from the preceding discharge, and then the following discharge was ignited at erased or uncharged areas. It was critical that a part of the energy stored in the dielectric layer and discharge gap by the previous discharge needed to be released to develop the next discharge. The results of this study provided an outlook for estimating the effectiveness of the DBD plasma system used in specific applications such as DBD for flow actuators or surface treatment where the use of unipolar DBDs at low frequency may be necessary.