ABSTRACT
This chapter considers instabilities driven by high-energy particles interacting with toroidicity-induced Alfven eigenmodes (TAE) and kinetic TAE (KTAE) modes. The role of high-energy particles can be played by fusion-produced a-particles and high-energy ions generated by neutral beam injection and radio-frequency heating. The chapter aims to generalize the preceding formalism to the case when the particles interact with both poloidal harmonics. It examines a general expression for the growth rate of TAE and KTAE modes due to high-energy particles. The chapter discusses the problem of excitation of TAE modes by trapped high-energy particles. The interaction of strongly circulating high-energy particles was studied by Fu and Van Dam in the zero-drift-orbit approximation. The effect of a finite orbit in the TAE mode instability was allowed for in assuming that the orbit width exceeds the inner layer of the mode but is smaller than the width of the outer region.
