Aachen PK 2003 – scientific programme
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P: Plasmaphysik
P 17: Poster III
P 17.8: Poster
Thursday, March 20, 2003, 17:30–19:15, Foyer
Analysis of the Intensity Ratio C2/CH Radiation from Different Plasmas in Hydrocarbons — •A. Zymara, U. Fantz, and K. Behringer — Lehrstuhl für Experimentelle Plasmaphysik, Institut für Physik, Universität Augsburg, D-86135 Augsburg
In plasmas containing hydrocarbons, radiation of CH (around 431 nm) and C2 (around 517 nm) can be detected. Since the radiation can be produced by different excitation mechanisms, i.e. direct excitation (e.g. CH + e− → CH∗ + e−) or dissociative excitation (e.g. CH4 + e− → CH∗ + e−), the contribution of each channel has to be investigated first. It turns out that the CH radiation either refers to CH or CH4 (depending on the gas mixture) whereas the C2 radiation refers directly to the C2 density. Therefore the intensity ratio of radiation from C2/CH provides information of the particle density of these species in a plasma. The intensity ratio is measured in different hydrocarbon plasmas (ECR source) with admixtures of He (CH4/He, C2H2/He, C2H4/He and C2H6/He). A strong variation of the intensity ratio is observed and will be compared with line ratios measured during gas puff experiments (CH4, C2H6) in the divertor of ASDEX Upgrade. The underlaying formation processes will be discussed also.