Kinetic Stability of Alpha Driven TAEs in ITER Plasmas

A hybrid gyrokinetic ions/fluid electron model is implemented in the Particle-in-Cell code GEM and used to study high-n TAEs in ITER. The adequacy of the model for simulating TAEs has been previously demonstrated\footnote{J. Lang, Y. Chen, S. E. Parker, and G-Y. Fu, Phys. Plasmas 16 102101 (2009)}, by comparing the simulated TAE mode frequency and structure with an eigenmode analysis, and the thermal ion kinetic damping with analytic theory. By using a global PIC code the effects of large orbit width and non-local mode structures can be accurately included. Damping rate due to numerical filtering is carefully monitored, and convergence with respect to particle number, grid resolution, etc., is thoroughly tested. The simulations show that the most unstable modes in ITER lie in the rage of $10