Chemical sputtering of carbon in Tore-Supra outboard pump limiter

Abstract The use of a large amount of carbon in tokamaks induces two major problems mainly due to the chemical sputtering: erosion and tritium retention. In the Tore-Supra outboard pump limiter, the in situ chemical sputtering yield of the carbon neutralizer plate has been studied. Investigation of methane and heavier hydrocarbon (C 2 D x and C 3 D y ) emission has been performed in ohmic and lower hybrid heated discharges, by means of mass spectrometry and optical spectroscopy. Simulation performed with a Monte Carlo code (BBQ) allows validation of the sputtering yield calculation method and show good agreement with experimental data.