Gross and net erosion balance of plasma-facing materials in full-W tokamaks

Gross and net erosion of tungsten (W) other plasma-facing materials in the divertor region have been investigated deuterium (D) helium (He) plasmas during dedicated experiments L- H-mode on ASDEX Upgrade after full-length experimental campaigns WEST tokamak. Net was determined via post-exposure analyses plasma-exposed samples full-size wall components, we conclude that same approach is applicable to gross if marker structures with sub-millimeter dimensions are used eliminate contribution prompt re-deposition. In plasmas, ELMs may exceed situation inter-ELM conditions by 1–2 orders magnitude while typically higher a factor 2–3. The largest impact attributed electron temperature role impurity mixtures weaker, even though both significant amounts impurities present edge plasmas. Impurities, hand, will lead formation thick co-deposited layers. We also noted increasing surface roughness, strongly suppressed growth layers enhanced. He increased compared D due mass charge states plasma particles, resulting from larger energies sheath acceleration, but strong fluxes can result apparent deposition divertor. Our results comparable indicate typical net-erosion rates 0.1–0.4 nm s?1, excluding immediate vicinity strike-point regions.