New directions for computer simulations and experiments in plasma–surface interactions for fusion: Report on the Workshop (Oak Ridge National Laboratory, Oak Ridge TN, USA, 21–23 March 2005)

Designing the interface between a thermo-nuclear plasma and the solid material environment is one of the most stringent technical challenges of ITER as well as for the successful development of future fusion power reactors. Although carbon-based materials are recognized to have superior thermal–mechanical properties, they could retain high levels of tritium by co-deposition with eroded carbon that could severely constrain plasma operations. Thus, a mix of several different plasma-facing materials is now proposed in ITER to optimize the requirements of areas with different power and particle flux characteristics. The need to base such an optimization on reliable material properties is well accepted. In this regard, questions arise over what is the best use of existing experimental facilities for surface experiments and what are the possible qualitatively new developments which could be pursued by exploitation of the greatly enhanced computational capability which is on the horizon. To address such questions, a workshop dedicated to the identification of possible new directions for advanced computer simulations and laboratory experiments in the area of plasma–surface interactions relevant to fusion (PSIF), and especially to ITER, was held at the Oak Ridge National Laboratory from 21 to 23 March 2005. Representatives from many fusion research laboratories attended and 25 talks were given. The workshop talks dealt with identification of needs from the perspective of integrated fusion simulation and ITER design, recent developments and perspectives on the computation of plasma-facing surface properties using the current and expected new generation of computation capability, and with the status of dedicated laboratory experiments which characterize the underlying processes of PSIF. The proceedings of the workshop will be published in Physica Scripta. This workshop summary will discuss contributions on the needs for ITER and integrated fusion predictive simulation codes, as exemplified in the US by the Fusion Simulation Project (FSP), and describe the status of models for fusion plasma experiments, of surface experiments and of the state-of-the art in simulation of surface properties. Finally, the conclusions and recommendations of the workshop participants for further work will be presented.