Simulations of divertor target material composition during tokamak plasma operation with continuous boron powder injection*

Powder injection may be an effective method to continuously condition fusion device walls during operation. A key scientific question regarding real-time wall conditioning is the feasibility of maintaining a surface layer of injected material (e.g., boron) on a PFC substrate (e.g., carbon or tungsten) while it is undergoing erosion and redeposition. To address this issue, experiments with real-time wall conditioning by boron powder injection have recently been performed in DIII-D [1], which will be interpreted by means of multi-scale numerical simulations. Detailed calculations of the plasma sheath and surface composition resulting from the boron impurity flux on a divertor target will be presented. Impurity fluxes are calculated using the coupled codes UEDGE and DUSTT for plasma edge and dust physics, respectively. The particle-in-cell code hPIC is coupled to the binary collision approximation code F-TRIDYN to determine the surface response and the impurity flux implantation. Simulated material composition of the target after real-time boronization will be presented.

[1] Bortolon et al. this conference