Imitation of deuterium plasma interaction with the surface of carbon materials in gaseous divertor conditions

The experiments on simulation of gas divertor conditions were done in the LENTA facility under interaction of a plasma flow with neutral gas. The samples of carbon materials were exposed in a steady-state deuterium plasma (ion energy 5 eV, ion flux 5×1021 m−2 s−1, fluence 1026 m−2) at 1470 K (MPG-8) and at 1320 K (SEP NB31). Heavy deuterocarbon molecules (C2D2, C2D4, C2D6) were observed in mass spectra of the discharge. This fact and high erosion yields show the presence of chemical erosion. Deuterium accumulation in carbon materials was studied by elastic recoil detection analysis. The integral deuterium content is 6×1018 m−2 in SEP NB31 and 1.95×1019 m−2 in MPG-8. The profiles of C and Mo atom distributions in deposited layer on Mo collector is ‘X’-like. Carbon atoms distribution in deposited layer on Si is uniform. The integral deuterium content in co-deposited layers is 1.4×1021 m−2 on Si and 4.8×1020 m−2 on Mo. A globular structure of co-deposited layer on Mo collector was found.