Ruptures in the box? Metallic melt pools, flying droplets and adhered dust in fusion devices

The interdisciplinary field of plasma material interactions encompasses all physical processes that lead to the exchange of particles, momentum and energy between plasmas and condensed matter bodies. Modelling of the interface between the plasma and the fusion reactor wall is a highly challenging task as the problem involves various aspects of disparate physics disciplines. On one side of ‘the border’, complicated plasma effects are dictated by classical electromagnetism. Near the interface, intense plasma-material interactions are governed by quantum mechanics. On the other side, the metallic melt (produced by incident heat loads) evolves according to the fluid mechanics laws. In addition to solid or liquid material boundaries surrounding plasmas, there are also dust particles, a by-product of plasma-surface interaction, whose remobilization from surfaces and collisions with the vessel are described by contact mechanics and impact mechanics. In this talk, we discuss some of the microscopic processes occurring on the plasma-material boundaries and modelling approaches for predictive studies of metallic plasma-facing component damage under energetic transient events, including the relevant issue of dust transport and in-vessel accumulation.