IT/P6-7 Integrated Modelling for ITER in EU

The ITER Scenario Modelling Working Group (ISM WG) is organised within the European Task Force on Integrated Tokamak Modelling (ITM-TF). The main responsibility of the WG is to advance a panEuropean approach to integrated predictive modelling of ITER plasmas with the emphasis on urgent issues, identified during the ITER Design Review. Three major topics were selected, which are considered as urgent and where the WG has the best possible expertise. These include modelling of current profile control, modelling of density control and impurity control in ITER (the two last topics involve modelling of both core and SOL plasma). Different methods of heating and current drive are tested as controllers for the current profile tailoring during the current ramp up in ITER. These include Ohmic, NBI, ECRH and LHCD methods. Simulation results elucidate the available operational margins and rank different methods according to their ability to meet different requirements. A range of “ITER-relevant” plasmas from existing tokamaks were modelled. Simulations confirmed that the theory-based transport model, GLF23, reproduces the density profile reasonably well and can be used to assess ITER profiles with both pellet injection and gas puffing. In addition, simulations of the SOL plasma were launched using both H-mode and L-mode models for perpendicular transport within the edge barrier and in the SOL. Finally, an integrated approach was also used for the predictive modelling of impurity accumulation in ITER. This includes helium ash, extrinsic impurities (like argon) and impurities coming from the wall (including tungsten). The relative importance of anomalous and neo-classical pinch contributions towards impurity penetration through the edge transport barrier and further accumulation in the core was assessed. a) See annex to M. Watkins et al, Fusion Energy 2006 (Proc. 21 IAEA Conf., Chengdu, 2006) IAEA Vienna