Simulations of Effects of Plasma Parameters and Geometry on ITER Performance

The dependence of ITER fusion power production, temperature and density pedestals, and core profiles on varying magnetic-q, edge density fueling strength, neoclassical transport, magnetic field strength, alpha-heating, circular, elongated and general geometries are examined. It should be noted that the quasilinear model used in the simulations stays within the accuracy of 10^-2 of a fully nonlinear approach. Simulations are made with the same model and gridsize over the whole radial profile. It is found that a large edge q tends to provide hollow density while a small edge q gives normal density profile. The rise in the source of the edge particle increases the density of the edge and the reaction rate close to the edge increases temperature fluxes, resulting in weak pedestal barriers. When neoclassical transport is turned off or the strength of B-field is increased, pronounced edge barriers are identified.  The slope of the H-mode pedestal is found to be reduced due to the alpha-heating. In general geometry, there are weaker ETBs, comparable ITBs, but a higher edge particle barrier than in elongated geometry. Higher density near the edge, on the other hand, causes more wall erosion, so elongated geometry might be the best option.