Berlin 2014 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
P: Fachverband Plasmaphysik
P 19: Poster Session - Low Temperature Plasmas
P 19.12: Poster
Wednesday, March 19, 2014, 16:30–18:30, SPA Foyer
Comparison of the measured and modeled N2(A3Σu+) metastables density in diffuse nitrogen barrier discharges — •Sebastian Nemschokmichal and Jürgen Meichsner — Universität Greifswald
The absolute density of the N2(A3Σu+,v=0) metastable is measured by laser-induced fluorescence spectroscopy in a diffuse nitrogen barrier discharge. Besides, the measured external electrical characteristics of the discharge are taken to determine the time dependent electron density and the rate coefficients for the excitation of the nitrogen metastables in an 1D-model for the nitrogen metastables density. As depletion processes, the pooling reaction of two metastables, the quenching with nitrogen atoms and the diffusion to the walls are considered in the model. Both the measurement and the simulation show an increase in metastables density during the discharge pulse and a decrease afterward. The measured axial metastables density profiles differ from the modeling, probably because of missing loss processes during the discharge pulse. Besides the comparison with the measurements, the model enables the calculation of the secondary electron emission by metastables to estimate the influence of this process on the discharge ignition. The calculation points out that the metastables density is large enough to have a significant influence on the formation of the diffuse discharge mode. Nevertheless, the modeled metastables diffusion current to the cathodic dielectric shows a bottleneck at the beginning of the discharge pulse caused by the delayed metastables production with respect to the discharge pulse.