Surface interactions and conditioning techniques in tokamaks

摘要: Abstract It now appears that the removal of oxygen from surfaces a fusion device requires carefully generated hydrogen plasma where chemical effects are allowed to dominate. Two critical parameters must be considered: (1) temperature, and (2) plasma-wall sheath potential. Increasing either these two beyond certain values reduces rate at which is removed (in form H2O). For best results, bulk outgassing reduced by baking chamber moderate temperatures as in other high vacuum applications. Oxygen applied results corresponding increase level plasma, while impurities filling gas do not normally play significant role. Effective surface densities close 1% monolayer have been obtained.