Publications in Scientific Journals:

S. Dai, A. Kirschner, J. Sun, D. Tskhakaya, D. Wang:
"Modelling of surface roughness effects on impurity erosion and deposition in TEXTOR with a code package SURO/ERO/SDPIC";
Nuclear Fusion, 54 (2014), 1230151 - 12301511.

English abstract:
The roughness-induced uneven erosion-deposition behaviour is widely observed on plasma-wetted surfaces in tokamaks.
The three-dimensional (3D) angular distribution of background plasma and impurities is expected to have an impact on the
local erosion-deposition characteristic on rough surfaces. The investigations of 13C deposition on rough surfaces in TEXTOR
experiments have been re-visited by 3D treatment of surface morphology to evaluate the effect of 3D angular distribution
and its connection with surface topography by the code package SURO/ERO/SDPIC. The simulation results show that the
erosion/deposition patterns and evolution of surface topography are strongly affected by the azimuthal direction of incident flux.
A reduced aspect ratio of rough surface leads to an increase in 13C deposition due to the enhanced trapping ability at surface
recessions. The shadowing effect of rough surface has been revealed based on the relationship between 3D incident direction
and surface topography properties. The more realistic surface structures used by 3D SURO can well reproduce the experimental
results of the increase in the 13C deposition efficiency by a factor of 3-5 on a rough surface compared with a smooth one. The
influence of sheath electric field on the local impact angle and resulting 13C deposition has been studied, which indicates that
the difference in 13C deposition caused by sheath electric field can be alleviated by the use of more realistic surface structures.
The difference in 13C deposition on smooth graphite and tungsten substrates has been specified by consideration of effects of
kinetic reflection, enhanced physical sputtering and nucleation.

edge plasma, surface roughness, Monte Carlo methods

Created from the Publication Database of the Vienna University of Technology.