Methane Production from Carbon under Combined Electron and Atomic Hydrogen Bombardment: Evidence for a Synergistic Effect?

Abstract
Carbon is in widespread use as a first wall material for fusion experiments. Recent reports on the existence of a strong synergistic effect, when carbon is bombarded simultaneously by atomic hydrogen and electrons, create concern over this use of carbon. Such an effect could result in an unacceptably high chemical erosion of the walls and detrimental release of impurities into the plasma and fuel recycling system. Contrary to these reports, the authors have observed only a weak synergistic effect when carbon samples were strongly baked and the experiments performed in a specially cleaned UHV system.