Materials experience with tokamak plasmas

摘要: The primary effects of using various wall and limiter materials have been in the amount kind impurities they introduce into plasma. employed to date include gold, stainless steel, inconel, glass, alumina titanium for first walls carbon, alumina, silicon carbide, boron molybdenum, tantalum, tungsten limiters divertors. Limiter surfaces bear brunt plasma bombardment so typically far out proportion their relative size. ratio bombarded area that is order 1 103. The effect per se on often largely masked by coatings foreign substances. Carbon oxygen compounds are most abundant observed with surface analysis techniques this correlates well spectroscopic observations which show carbon levels 1–6% typical tokamak plasmas. Metals intermediate atomic numbers such as Fe, Ni, Cr Ti usually constitute less than 1% density. Limiters normally principal contributors heavy metal contamination many Plasma act reduce energy stored through line, bremsstrahlung recombination radiationi Heavy metals particularly bad since radiated power a strong function number, ~Z3.7. As consequence tokamaks now employ either or steel limiters.