Optical study of a diffuse bipolar nanosecond pulsed dielectric barrier discharge with different dielectric thicknesses in air

In this paper, a bipolar nanosecond high-voltage pulse power supply with about 20 ns rising time is employed to generate a diffuse dielectric barrier discharge using dielectric plates of different thicknesses. Dielectric thickness, which is regarded as an important discharge parameter, can improve diffuse discharge characteristics. Both the images of the diffuse dielectric barrier discharge and the optical emission spectra with different dielectric thicknesses are recorded successfully under severe electromagnetic interference. The effects of the discharge gap distance, pulse peak voltage, and pulse repetition rate on the emission intensity of N₂ (C³Π _u → B³Π _g ) of nanosecond pulsed dielectric barrier discharge with different dielectric thicknesses were investigated. It was found that increasing dielectric thickness is not conducive to acquiring a larger area of diffuse discharge. Also, the intensity of discharge decays and the discharge volume constricts in a horizontal direction with increasing dielectric thickness. The experimental result also shows that the emission intensity of N₂ (C³Π _u → B³Π _g ) decreases with the increase of the dielectric thickness and the discharge gap distance, but rises with both increasing both pulse peak voltage and pulse repetition rate.