Toroidal Alfven eigenmode experiments in TFTR

In toroidal magnetically confined plasmas, eigenmodes of Alfven waves can be destablized by energetic ions with velocities comparable to the Alfven velocity. With the advent of tokamak experiments in which populations of energetic ions could be introduced by neutral beam injection, radio frequency wave heating or by fusion reactions, major advances have been made in Alfven eigenmode research in the past ten years. After introducing the basic concepts on the Alfven eigenmode instability, data on this subject from the Tokamak Fusion Test Reactor (TFTR) are briefly described, emphasizing the interplay between experiment and theory.