ITER relevant ICRF heating scenarios with large ion heating fraction

The merits of a large ion heating fraction for the performance of a tokamak reactor are investigated. The abilities of different ICRF heating scenarios in providing significant ion heating are discussed. The 3 He minority scenario is found to be the most suitable scenario for a reactor. Simulations of ITER relevant scenarios suggest that the bulk ion heating fraction is in the range of 70% for most of the heating phase. The benefits of a large ion heating fraction are then discussed in the framework of transport simulations. In particular, a large ion heating fraction is shown to lead to an improved control over the path to ignition. Finally, the implications of a reduced size ITER are discussed. The steady state performance with 3 He minority scenario is improved by 30% as compared with pure electron heating schemes.