Electric and spectroscopic analysis of a pure nitrogen mono-filamentary dielectric barrier discharge (MF-DBD) at 760 Torr

Mono-filamentary dielectric barrier discharge (MF-DBD), occurring within 1 mm gap of atmospheric pressure pure nitrogen and operating with a sinusoidal electric supply at about 8 kHz, is studied in this paper. A thorough electrical analysis allows experimental determination of the ignition and extinction voltages, respectively (15 750 +/- 50) V and (2097 +/- 7) V, the injected energy (158 +/- 2) J and charge (17.22 +/- 0.22) nC in a single filament. The mean axial reduced electric field is equal to (644 +/- 2) Td at ignition. An empirical technique is proposed to evaluate these discharge parameters by avoiding bulky calculations. Optical emission spectroscopic measurements of the vacuum ultraviolet (VUV), ultraviolet (UV), visible and near infrared (IR) emissions are presented and discussed. Two atomic nitrogen lines attributed to the decay of the N[2s(2)p(2)3s P-2] triplet towards N[2s(2)2p(3) D-2 degrees] level are observed at 150 and 175 nm, together with the Lyman-Birge-Hopfield system (N-2[a (1)Pi(g)] -> N-2[X (1)Sigma(+)(g)]) in the VUV range. The second positive system (N-2[C (3)Pi(u)] -> N-2[B (3)Pi(g)]) dominates the UV and visible-blue spectra. The (0-0) transition of the first negative system (N-2(+)[B (2)Sigma(+)(u)] -> N-2(+)[X (2)Sigma(+)(g)]) peaking at 391.4 nm, the first positive system (N-2[B (3)Pi(g)] -> N-2[A (3)Sigma(+)(u)]) and the Herman IR transitions (N-2[C ''(5)Pi(u)] -> N-2[A'(5)Sigma(+)(g)]) are also present. Both our VUV and near IR spectra are consistent with recently reported results in hollow cathode and cylindrical DBDs. The electrical and spectroscopic experimental results reported here are useful for ongoing and forthcoming modelling of filamentary nitrogen dielectric barrier discharges.