Modeling the vapor shielding of a liquid lithium divertor target using SOLPS 4.3 code

摘要

In this letter, we report the very first results of SOLPS4.3 simulations of a liquid lithium (Li) divertor, including vapor shielding effects. A peculiarity of Li as a target coating material is the strong dependence of the erosion rate on the target temperature. We have implemented a new erosion model in SOLPS, taking this dependence into account. Simulations of the T15-MD tokamak divertor with Li-coated divertor targets have been performed. Li erosion is determined by physical sputtering, evaporation, and thermal sputtering. The results of the simulations show that a shielding effect occurs, providing a reduction of the target heat flux to values below 8 MW m~(-2). At the same time, the upstream plasma dilution in the high-power regimes, where shielding is most efficient, is very strong, meaning that in practical terms, it may be difficult to rely on the shielding effect for heat flux control in the configuration considered.