Nanosecond pulsed uniform dielectric barrier discharge in atmospheric air: A brief spectroscopic analysis

The paper proposes a simple and convenient approach to represent the discharge uniformity of nanosecond-pulse dielectric barrier discharge (DBD) in air by observation of the ratio of N-2(+) (B-3 Sigma(+)(u) -> X-3 Sigma(+)(g), 0-0, 391.4 nm) to N-2 (C-3 Pi(u) -> B-3 Pi(g), 2-5, 394.3 nm) intensities. The DBDs at different pulse peak voltages, discharge gap distances, dielectric materials and thicknesses were investigated by recording their single-pulse-shot discharge images and N-2(+)-/N-2 ratios to verify the feasibility of the above innovative approach. The results show that the ratios of N-2(+)-/N-2 are in the range of 0.18-0.6within our experimental parameters, which is respect to the reduced electric field (E/N, where E is the field strength and N is gas number density) strength of 260-440 Td (1 Td = 10(-17) V.cm(2)). And it is indicated that a lower N-2(+)-/N-2 ratio would be found in a higher pulse peak voltage or/and a lower discharge gap distance, which benefits for improving the discharge uniformity of nanosecond-pulse DBD. The thickness and permittivity of dielectric material also affect the E/N strength and discharge uniformity to a certain extent, but the effects are ambiguous due to additional factors of dielectric materials. In addition, the theoretical basis and application scope of this approach were also discussed. (C) 2018 Elsevier B.V. All rights reserved.