Chemical sputtering from the pump limiter neutralizer in Tore Supra

Carbon is widely used as plasma facing component in present fusion devices and is proposed for the divertor plates of ITER. The improvement in the con trol of the plasma edge parameters, limiting the power flux and the electro n temperature in the divertor leads to an acceptable erosion rate of carbon due to physical sputtering and radiation enhanced sublimation. In these co nditions, chemical sputtering will probably be the main mechanism of erosio n for the carbon plate. Tn situ measurements of hydrocarbon production on t he neutralizer plate of an outboard pump limiter have been obtained in Tore Supra. CD4 has been monitored by means of optical spectroscopy and mass sp ectrometry for different electron temperatures and densities. Simulations p erformed with a Monte Carlo code (BBQ), show a good agreement with experime ntal data at high flux, low electron temperature. (C) 1999 Elsevier Science B.V. All rights reserved.