MHD stability of the ITER pedestal and SOL plasma and its influence on the heat flux width

Proceedings of the 21st International Conference on Plasma-Surface Interactions in Controlled Fusion Devices Kanazawa, Japan May 26-30, 2014 MHD stability of ITER plasmas has been analyzed for QDT = 10 edge and SOL plasma conditions, showing that the SOL plasma is MHD stable down to pressure gradient scale lengths of kp 1 mm, but that MHD pedestal plasma stability can limit kp to values of 5–8 mm just inside the separatrix. Modelling of the corresponding plasma conditions with the SOLPS code shows that heat flux widths kq 1.2–1.5 mm can be obtained which are compatible with kp 5–8 mm. This is due to the fact that the ITER divertor plasma enters the high recycling regime at low values of separatrix densities (4.0 1018 m3), which leads to the appearance of a region with reversed flow near the separatrix, modifying plasma transport and leading to high SOL density gradient scale lengths and divertor plasma pressures near the separatrix.