Optical study of diffuse bi-directional nanosecond pulsed dielectric barrier discharge in nitrogen.

In this study, a bi-directional high voltage pulse with 20 ns rising time is employed to generate diffuse glow-like dielectric barrier discharge plasma with very low gas temperature in N2 using needle-plate electrode configuration at atmospheric pressure. Both the diffuse nanosecond pulsed dielectric barrier discharge images and the optical emission spectra of the discharge are recorded successfully under severe electromagnetic interference. The effects of pulse peak voltage, pulse repetition rate, and the concentrations of Ar and O2 on the emission intensities of NO (A2Σ→X2Π), OH (A2Σ→X2Π, 0-0), N2 (C3Πu→B3Πg, 0-0, 337.1 nm), and N2+ (B2Σu+→X2Σg+, 0-0, 391.4 nm) are investigated. The effects of the concentrations of Ar and O2 on the discharge diffuse performance are also studied. It is found that the emission intensities of NO (A2Σ→X2Π), OH (A2Σ→X2Π, 0-0), N2 (C3Πu→B3Πg, 0-0, 337.1 nm), and N2+ (B2Σu+→X2Σg+, 0-0, 391.4 nm) rise with increasing pulse peak voltage, pulse repetition rate, and the concentration of Ar, but decrease with increasing the concentration of O2. The main physicochemical processes involved are also discussed.