Radiative Divertor Modelling for ITER and TPX

The B2.5 code for two‐dimensional multi‐species fluid modelling of the tokamak edge plasma is described and is applied for a parameter study of the effect of impurity seeding in ITER and TPX. Our modelling indicates that ITER must operate at an edge density of about 6.0 × 10 19 /m 3 and the extended performance TPX must operate at an edge density of about 5.0 × 10 19 /m 3 in order to obtain a robust divertor solution based on impurity radiation from the edge plasma only at neon concentration below 0.6% or argon concentration below 0.4%. For both devices, a high‐recycling divertor solution relying on impurity radiation from core and edge together appears very credible.