Pulsed filament current characteristics in dielectric barrier discharge

The magnitude distributions of filament current in dielectric barrier discharge were investigated under different supply voltage, barrier thickness and gap size. The experiment was carried out using two planar electrodes powered by 5 kHz and 2 kV power supply. One filament current could only affect a small space in the discharge gap. The number of filaments occurred depended on the rise rate of the supply voltage. Filament currents were measured and found to conform to the Normal distribution, with standard deviation weighted 40% of the mean value with 0.2 mm barrier thickness and 0.2 mm gap. The filament current was measured to be 4.7 times greater than the external current. The magnitude of filament current didn´t change with increased supply voltage but the number of filaments increased. The filament current didn´t change when increasing the gap size from 0.1 mm to 0.3 mm, but the external current increased with the gap size. With increased barrier thickness from 0.1 mm to 0.3 mm, both filament current and external current decreased by three times. The magnitude of the external current depends on the ratio between gap capacitance and dielectric barrier capacitance.