Effect of lower hybrid wave heating on alpha-particle dynamics

Effects of lower hybrid wave (LHW) heating on alpha particle dynamics in a large Tokamak such as TFTR are investigated numerically. By use of a single particle code which includes the interaction with LHW, the diffusion coefficients of the particles in real and magnetic moment spaces are evaluated. The characteristic feature of the wave-particle interaction is that the alphas interact with almost whole poloidal cross-section of the wave due to their large Larmor radii. It is found that LHW heating causes spatial diffusion as well as velocity diffusion and the characteristic time of orbit loss due to stochastic diffusion of the alpha particles with rather large banana width is of the order of or shorter than their slowing-down time.