Bochum 2015 – scientific programme

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P: Fachverband Plasmaphysik

P 9: Diagnostics I

P 9.5: Talk

Tuesday, March 3, 2015, 12:05–12:20, HZO 30

Transient emission from a ns-discharge — •Beatrix Biskup, Dirk Luggenhölscher, and Uwe Czarnetzki — Institute for Plasma and Atomic Physics, Ruhr-University, 44780 Bochum, Germany

To investigate transient continuum emission out of a ns-pulsed micro-thin cathode discharge (µTCD), a time resolved optical emission spectroscopy between 210 nm - 710 nm was applied. This µTCD was pulsed at atmospheric pressure in argon gas with a trigger voltage of 1400 V. The measured pulse lenght of the discharge had a duration of only 5 ns, with a peak current of 10 A. A continuum emission between 300 nm and 600 nm together with wide Ar II lines at the ignition point could be detected with a relatively calibrated spectrometer. The continuum is probably caused by an argon excimer (Ar₂⁺). In addition to the temporal evolution, the plasma density and temperature were calculated from measured Stark-broadening profiles, for atomic and ionic lines (H_α, Ar I and Ar II). For atomic lines a density ∼10¹⁸ cm⁻³ and for ionic lines even higher densities near neutral gas density (∼10¹⁹ cm⁻³) were optained. The difference could be due to variing density regions in the discharge orifice which are investigated by spatially resolved measurements.