Absolute nitrogen atom density measurements by two-photon laser-induced fluorescence spectroscopy in atmospheric pressure dielectric barrier discharges of pure nitrogen

• Published in: Journal of applied physics 2009-10, Vol.106 (7), p.073302-073302-7
• Main Authors: Es-Sebbar, Et-Touhami, Sarra-Bournet, Christian, Naudé, Nicolas, Massines, Françoise, Gherardi, Nicolas
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ABSORPTION; ATMOSPHERIC PRESSURE; BOSONS; DIELECTRIC MATERIALS; ELECTRIC DISCHARGES; ELEMENTARY PARTICLES; ELEMENTS; EMISSION; EMISSION SPECTROSCOPY; Engineering Sciences; FLUID FLOW; FLUORESCENCE; FLUORESCENCE SPECTROSCOPY; GAS FLOW; IMPURITIES; LASERS; LUMINESCENCE; MANY-BODY PROBLEM; MASSLESS PARTICLES; MATERIALS; NITROGEN; NONMETALS; PHOTON EMISSION; PHOTONS; PLASMA DENSITY; PLASMA DIAGNOSTICS; PLASMA IMPURITIES; RECOMBINATION; SORPTION; SPECTROSCOPY; THREE-BODY PROBLEM; TOWNSEND DISCHARGE; WALL EFFECTS
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.3225569

In this paper, two-photon absorption laser induced fluorescence spectroscopy is used to follow the nitrogen atom density in flowing dielectric barrier discharges fed with pure nitrogen and operating at atmospheric pressure. Two different dielectric barrier discharge regimes are investigated: the Townsend regime, which is homogeneous although operating at atmospheric pressure, and the more common filamentary regime. In both regimes, densities as high as 3 × 10 14 ∕ cm 3 are detected. However, the N atoms kinetic formation depends on the discharge regime. The saturation level is reached more rapidly with a filamentary discharge. For a given discharge regime, the N atom density depends strongly on the energy dissipated in the plasma between the gas inlet and the measurement position, whether the energy is varied by varying the position of the measurements, the gas flow, or the dissipated power. Experiments performed in the postdischarge show that the N atom decay cannot be simply attributed to three-body recombination of atomic nitrogen with nitrogen molecules, meaning that other mechanisms such as surface recombination or gas impurities play a role.