Use of pre-ionization electrodes to produce large-volume, densely distributed filamentary dielectric barrier discharges for materials surface processing

Scaling up atmospheric pressure dielectric barrier discharges is a challenging prerequisite to expanding their industrial applications. In this study, we present the results of large-volume dielectric barrier discharges (DBDs) with a parallel plate electrode configuration having an electrode surface of 50 x 200 mm(2) and an interelectrode gap of 5 mm. Highly dense filamentary DBD plasma was stably generated over a large area using pre-ionization electrodes embedded in the one of electrodes. We show that the role of the pre-triggering system is crucial in producing a densely distributed filamentary discharge over the electrode surface, especially at the main discharge voltage values of 14.0-18.0 kVp-p and pre-ionization voltage of 7.0-10.0 kVp-p at the same frequency, ranging from 1 to 4 kHz. By tuning the phase difference between the pre-ionization and main discharge voltages to around 180 degrees, both discharge current amplitude and duration time per period of main DBDs are maximized. The present results indicate that such a large-volume DBD is extremely versatile and suited for a wide range of industrial applications.