非表示:
キーワード:
15th International Conference on Plasma Surface Interactions in Controlled Fusion Devices (PSI 15), Gifu, 2002-05-26 to 2002-05-31
要旨:
This paper reviews the erosion properties of high-Z plasma facing materials due to the
bombardment with typical impurity ions. The different impurity species present in today's fusion
experiments are compared in terms of their importance for erosion of high-Z metals, showing that C
is the main source of erosion. As example results are presented here from controlled ion beam
experiments on the temperature dependent erosion and deposition processes occurring during
bombardment of W by keV C-ions. It is shown that radiation enhanced sublimation (RES) and
diffusion are responsible for the observed temperature dependence. A new code was developed to
simulate the influence of thermally activated processes on the complex temperature dependence of
protective C layer growth on W during simultaneous bombardment by keV C and eV hydrogen
isotopes. To model RES, diffusion and chemical erosion of C the Monte Carlo program TRIDYN
was coupled with a newly developed diffusion code DIFFUSEDC and a chemical erosion module
YCEHM. This combination was validated by comparing calculated W erosion yields in D plasma
with C as main impurity to spectroscopically measured values from ASDEX Upgrade as well as ion
beam experiments using CH3+.
