Resonant excitation of shear Alfven perturbations by trapped energetic ions in a tokamak

Full text: A new analytic expression is derived for the resonant drive of high-n Alfvenic modes by ICRH-accelerated particles. This derivation includes finite-orbit-width effects, and the formalism is completely non-perturbative. The high-n limit is used to calculate the complex particle response integrals along the orbits explicitly. This new theory is applied to downward sweeping Alfven Cascade quasimodes completing the theory of these modes, and making testable predictions. These predictions are found to be consistent with experiments carried out on the Joint European Torus. (author)