Experimental studies on the behavior of carbon-containing molecules in the boundary plasma

This work continues an investigation of fusion reactor materials erosion and redeposition processes, whereby the molecular collision and transport processes of carbon-containing molecules in relation to erosion and redeposition in the fusion boundary plasma were investigated. For this purpose, the graphite target was exposed to laboratory-scale hydrogen plasma, whose parameters are close to a fusion boundary plasma that generates carbon containing molecules. Optical spectroscopy was employed to identify CH, C2 and H2 molecules in the plasma and the spatial distribution of their relative density was measured. In addition, equations and methods are proposed to determine the excitation temperatures of carbon-containing molecules. The spatial distributions of rotational and vibrational excitation temperatures were evaluated from the obtained C2 and CH emission spectra by fitting them with calculated spectra. We propose to test our method to monitor chemically sputtered particles near the actual Tokamak divertor.