HIGH-N STABILITY OF ALPHA-PARTICLE DRIVEN ALFVEN EIGENMODES

In the present work, we analyse the two dimensional (2-D) mode structu res and global stability of the Alfven branches, whose frequencies are close to the toroidicity induced Alfven continuum gap. The fully 2 D problem is solved using a two spatial-scale WKBJ formalism without emp loying perturbation theory in treating drive and damping terms. A code that solves the 2-D mode structures and global stability of the Alfve n branches is presented. Applications to a model toroidal equilibrium with ITER relevant plasma parameters are analysed. Results indicate th at no unstable modes are present in the considered reference scenario.