MAP MODEL FOR NONLINEAR ALPHA-PARTICLE INTERACTION WITH TOROIDAL ALFVEN WAVES

A map model has been developed for studying the nonlinear interaction of alpha particles with the toroidal Alfven eigenmodes. The map is con structed by assuming a linear interaction during a single poloidal tra nsit, which allows the study of the nonlinear interaction over many tr ansits. By using this map, analytic expressions are obtained for the p article nonlinear bounce frequency, and the wave amplitude threshold f or the onset of particle orbit stochasticity. The map model can also f acilitate self-consistent simulations which incorporate the time varia tion of the waves.