Plasma facing materials, the materials that line the vacuum vessel, experience particularly hostile conditions as they are subjected to high particle and neutron flux and high heat loads. Plasma facing materials must have high thermal conductivity for efficient heat transport, high cohesive energy for low erosion by particle bombardment and low atomic number to minimize plasma cooling. These contradictory requirements make the development of plasma facing materials one of the greatest challenges ever faced by materials scientists. Modeling has made, and continues to make, a valuable contribution to the understanding of the various processes involved in the radiation damage of plasma facing materials. The techniques used to model the effects of high thermal and particle flux range from ab initio techniques that study processes occurring on femtosecond timescales and nanometre length scales, to molecular dynamics for intermediate length and timescales and finite element models for macroscopic length scales and experimental timescales. The synergy between the effects of the plasma, high heat flux and particle flux presents particular challenges for modeling. In this review we summarise the potential candidates for plasma facing materials and describe the methods used for modeling the response of these materials to the conditions experienced in a fusion reactor.
