Hannover 2010 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 19: Poster: Low Temperature Plasmas II

P 19.3: Poster

Donnerstag, 11. März 2010, 16:00–18:00, Lichthof

Net emission coefficients for argon-iron plasmas with Stark broadening scaled to experiments — Martin Wendt, Marie-Emilie Rouffet, Heinz Schöpp, and •Dirk Uhrlandt — INP Greifswald e.V., Felix-Hausdorff-Str 2, 17489 Greifswald

This work presents values of the net emission coefficient for argon-iron plasmas at a pressure of 1 bar, temperatures from 1 to 30 kK and iron fractions from 0 to 100 %. The linewidths of electron Stark broadening, which is the dominant broadening mechanism at higher temperatures, are calculated according to Griem and then scaled to widths measured on a pulsed argon-iron welding arc. The net emission coefficient may be used as an approximation of the energy transport by radiation, which plays a decisive role in the formation of the temperature profile of free-burning, atmospheric arcs. The net emission coefficient circumvents the computational costs of ray tracing calculations, which are particularly high for welding arcs containing iron because it shows several thausand radiative transitions. The presented net emission coefficients take into account line emission, bound-free and free-free continua and they are compared with literature values. The line profile functions obey natural, resonance, Doppler, van der Waals, and electron and ion Stark broadening.