Berlin 2001 – scientific programme

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P: Plasmaphysik

P 11: Dusty Plasmas and Low Temperature Discharges (Poster Session)

P 11.25: Poster

Thursday, April 5, 2001, 12:30–15:00, AT2

Spectroscopical and optical investigations for the determination of plasma parameters near the electrodes of short arc lamps — •M. Kettlitz and H. Pursch — Institut für Niedertemperatur-Plasmaphysik, Friedrich-Ludwig-Jahn-Str. 19, 17489 Greifswald

It is the aim of the work to understand the operating conditions of thermal arcs in short arc lamps especially in the transition region from the arc to the electrodes. Spectroscopical and optical studies with a high spatial and temporal resolution are performed to measure the radial and axial distribution of the plasma parameters and to observe the shape of the arc attachment at the electrodes. Simultaneously the electrical parameters of the arc are recorded to verify the influence of the temporal variation of the energy input. The investigations are carried out at industrially manufactured short arc lamps which are operated with an electronic ballast. The discharge is established horizontally between pure tungsten electrodes in a xenon mercury atmosphere with additives of metal halides. The plasma temperature is measured using the radiance of the self reversal maxima of the optically thick Hg spectral line at 546 nm (Bartels method). First calculations provide temperatures of about 7000 K in the constricted plasma near the electrodes and temperatures below 6000 K in the centre of the arc between the electrodes.

This work is supported by the German Ministry of Education and Research (FKZ 13N7762).