Key Lab of Materials Modification by Laser, Ion and Electron Beans, Dalian University of Technology, Ministry of Education, Dalian 116024, China. Electronic address: [Email]
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 N2+ (B3Σu+ → X3Σg+, 0-0, 391.4 nm) to N2 (C3Πu → B3Πg, 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 N2+/N2 ratios to verify the feasibility of the above innovative approach. The results show that the ratios of N2+/N2 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·cm2). And it is indicated that a lower N2+/N2 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.
