A diffusive air plasma in bi-directional nanosecond pulsed dielectric barrier discharge

In this study, a diffuse dielectric barrier discharge in air is generated by a bi-directional nanosecond pulsed power supply using a needle-plate electrode configuration at atmospheric pressure. Time-resolved spectra of N(2)(C (3)Pi(u) -> B (3)Pi(g), 0-0, 337.1 nm) for both positive and negative pulse discharges are recorded under severe electromagnetic interference. It is found that the lagged time of the photocurrent pulse compared with the voltage pulse in the negative pulse discharge is about 50 times longer than that in the positive pulse discharge at 16 kV pulse peak voltage and becomes shorter with an increase in pulse peak voltage. In addition, the gas temperature of the air plasma is determined to be approximately 395 K by measuring the optical emission spectra of the first negative band of N(2)(+)(B (2)Sigma(+)(u) -> X (2)Sigma(+)(g), 0-0, 391.4 nm).