ALPHA-PARTICLE-DRIVEN NONIDEAL TOROIDAL ALFVEN EIGENMODES

The excitation of Toroidal Alfven Eigenmodes by high energy alpha part icles is examined. Specifically, the kinetic alpha-particle response i s retained directly in the linear mode coupling-equations, and represe nts a driving source proportional to the spatial gradient of the alpha distribution. The model is an extension of the recently studied high- m, large-aspect-ratio, asymptotic boundary layer theory of the nonidea l TAE [1], and provides a self-consistent method for the determination of the instability threshold and growth rate of the excited TAE. Anal ytical and numerical stability thresholds are presented for the simple case of slowly varying density and shear.