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 maintain ed 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 signific ant deleterious effect on the core power balance, without producing si gnificant changes in the current profile that might trigger a disrupti ve collapse of the current channel and without inducing an H to L mode transition. These results suggest that an impurity seeded radiative m antle should be considered as part of the solution to the divertor hea t load problem in ITER and other future tokamaks.