Scaling of ITER divertor parameters – interpolation from 2D modelling and extrapolation

Detailed modelling studies of the divertor plasma for ITER have been carried out. Using these results, scaling relationships are developed linking SOL power, density, throughput, pumping speed, peak divertor power load, and helium density for ITER conditions in order to systematise the results and to extrapolate them beyond the range presently covered by the simulations. The key parameter for the scalings is the neutral pressure in the divertor. Both peak power load and helium density vary as the square of the power at constant pressure. The inclusion of helium elastic collisions reduces the helium density and leads to a steeper reduction with increasing pressure. Variants of the input conditions, i.e. different geometry, no helium elastic collisions, carbon walls, are also discussed, the consistency of the edge modelling with conditions required in the core is treated, and extrapolation to higher power operation is carried out.