CASTOR-K: Stability analysis of Alfven eigenmodes in the presence of energetic ions in tokamaks

A hybrid magnetohydrodynamic-gyro-kinetic model is developed for the stability analysis of global Alfven waves in the presence of energetic ions. The ideal MHD model is extended to take into account the perturbed parallel electric field and the finite Larmor radius which are relevant for high temperature plasmas. The gyrokinetic formulation fully includes the tokamak geometry and the effects of non-standard orbits of energetic ions, which experience large excursions away from the magnetic flux surfaces. The algorithms implemented in the CASTOR-K code are presented together with tests of the numerical accuracy. The orbit integration algorithms are optimized. An efficient algorithm is developed for evaluation of the wave-particle energy exchange expressed by the quadratic form delta W-hot. (C) 1999 EURATOM.