Self-consistent modelling of a liquid metal box-type divertor with application to the Divertor Tokamak Test (DTT) facility: Li vs. Sn

In the present work a model for a liquid metal (LM) box-type divertor is presented, aimed at including the most relevant aspects of its rich physics, as well as some engineering elements. Given the upstream plasma conditions and for a fixed divertor geometry, the model self-consistently evaluates the plasma heat and particle flux on the LM surface, the thermodynamic state of the metal (liquid and vapor) in the divertor boxes and the temperature distribution in the solid walls. The model is then applied to the Divertor Tokamak Test (DTT) facility, which is currently being designed in Italy, comparing Li and Sn as possible LM choices, in terms of operating temperatures and of metal vapor flux from the divertor box system towards the main plasma chamber.