AN IMPURITY SEEDED RADIATIVE MANTLE FOR ITER

Self-consistent, coupled transport/MHD/scrape-off layer (SOL) divertor calculations indicate that a stable, radiating mantle can be maintained just inside the separatrix by iron impurity injection into the SOL in an ITER EDA model. The power flux to the divertor plate is reduced thereby by an order of magnitude or more. This reduction of the power exhausted to the divertor is predicted to be achieved without significant deleterious effect on the core power balance, without producing significant changes in the current profile that might trigger a disruptive collapse of the current channel and without inducing an H to L mode transition. These results suggest that an impurity seeded radiative mantle should be considered as part of the solution to the divertor heat load problem in ITER and other future tokamaks.