Importance of Plasma-Wall Interaction.The understanding and control of the interaction of a hotplasma with the surfaces of the surrounding first solid walls hasbeen recognized in recent years to be one of the key problemsin fusion research which should be solved if cleaner plasmaswith higher densities, longer confinement times and highertemperatures are to be achieved. The impurity concentrationsobserved in today's plasmas determine the achievable plasmaparameters and are still higher than the tolerable concentrationsin a future fusion reactor. Another aspect of plasma-wall interactionis the re-cycling of the plasma at the first wall which isdetermined by reflection, trapping, diffusion and release ofhydrogen in the solids. This is closely related to the problemsof re-fuelling and tritium inventory, which are a major concern inthe design of DT-experiments as, e.g. in TFTR and JET.
Fascinating physics at the edge of magnetic fusion devices