Investigation of detached recombining deuterium plasma and carbon chemical erosion in the toroidal divertor simulator NAGDIS-T

Detached deuterium recombining plasma has been generated in the toroidal divertor simulator. The electron temperature (0.1–0.4 eV) and density (∼1018 m−3) in the detached plasmas were evaluated with a spectroscopic method using a series of deuterium Balmer line emission from highly excited levels and the Stark broadening of D(2–12). We have investigated the role of volume plasma recombination through Electron–Ion Recombination (EIR) and Molecular Activated Recombination (MAR) processes. Moreover, the carbon erosion in the detached deuterium plasma has been studied with a weight loss method. It is found that deuterium neutrals generated by EIR process could have strong influence on the carbon chemical erosion.