Augsburg 2006 – scientific programme

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P: Plasmaphysik

P 4: Diagnostik 1; Niedertemperaturplasmen / Plasmatechnologie 2; Magnetischer Einschluß 2

P 4.23: Poster

Monday, March 27, 2006, 17:00–19:00, Flure

The development of microdischarges of barrier discharges in N₂/O₂ mixtures - experimental investigations and modelling — •H. - E. Wagner¹, Yu. V. Yurgelenas², K. V. Kozlov³, and R. Brandenburg⁴ — ¹Institute of Physics, University of Greifswald, Domstr. 10a, 17489 Greifswald, Germany — ²General Physics Institute, Russian Academy of Science, Vavilova str. 38, Moscow 119991, Russia — ³Department of Chemistry, Moscow State University, Moscow 119899, Russia — ⁴Institute of Low Temperature Plasma Physics (INP), Jahnstr. 19, 17489 Greifswald, Germany

The spatially resolved cross-correlation spectroscopy (CCS) was used for systematic investigations of the barrier discharge (BD) in N₂/O₂ mixtures at atmospheric pressure. The spatio-temporal distributions of the microdischarge (MD) radiation intensities were recorded for the spectral bands of the (0-0) transitions of the 2^nd positive (λ = 337.1 nm) and 1^st negative system of molecular nitrogen (λ = 391.4 nm). The velocities of the cathode-directed ionization waves, the local electric field and the relative electron densities were evaluated from the CCS data. In the middle of the gap, the MD channel diameter was found to be about 0.3 mm and to expand towards both electrodes. On the dielectrics, outward propagating discharges were observed. A computational model of the BD is proposed, to explain the MD formation in short (1-2 mm) air gaps by a Townsend mechanism. The two-dimensional dynamics of the MD development and the channel radiation for the second positive system of nitrogen are simulated. The proposed model explains satisfactorily the experimental results.