Search for Ion Heating Scenarios in Burning D-T Plasmas with ICRH.

Paper in proceeding, 2011

Various ICRH scenarios relevant for the D-T phase of the JET tokamak operation are studied. It is known that an enhancement of the heating efficiency in the mode conversion regime (when the concentrations of D and T species are comparable) is possible due to the constructive interference of the reflected fast waves. Such a heating enhancement in D-T plasma is investigated first for the JET-like conditions for both dipole and +π/2 ICRH antenna phasings, and for T concentration varied from 0 to 100%. It is shown that most of the considered scenarios suffer from the parasitic absorption caused by the presence of fusion-born alpha-particles and NBI-produced fast particles. It is found that thermal ion heating becomes dominant in tritium-rich plasmas with T concentration ~80%. This scenario is compared with the alternative 3He minority ICRH scenario in D:T=50:50 plasmas.