Modelling radiative power exhaust in view of DEMO relevant scenarios

Power exhaust in future electricity producing fusion device features difficulties which, compared to ITER, are harder to tackle in terms of operational control requiring an improved physics understanding. Primarily, the heat flux problem must be solved in order to allow plasma facing components (PFCs) to withstand a maximum heat flux not exceeding 5MW/m² in steady state on timescales lasting days or weeks. For a given P_loss/R, with P_loss being the power arriving from the core into the pedestal region, a total dissipated fraction f_diss=P_diss/P_loss close to 95% or higher is required to reduce the total target heat load qt . P_diss covers the diverted plasma edge region, the full scrape-off layer (SOL) and parts of the confined core region and thus accounts for _losses from (impurity) radiation, transport towards the main-chamber and charge-exchange collisions with neutrals.