Simulation of Fast Alfv\'en Wave Interaction with Resonant Ions in Tokamaks Using Monte Carlo Orbit Code Coupled with Full Wave Code

Recent DIII-D fast Alfv\’en FW wave current drive experiments have demonstrated much stronger beam ion acceleration at 4th harmonic than at 8th harmonic. Recent \hbox{C-Mod} fundamental heating experiments have also measured rf-induced non-Maxwellian tails. The Monte-Carlo code, ORBIT-RF provides a comprehensive physics package to investigate the interactions between non-Maxwellian ions with finite orbit and FW. ORBIT-RF coupled with TORIC4 wave fields using a single dominant toroidal and poloidal Fourier mode reproduces qualitatively experimental observations in both \hbox{C-Mod} and \hbox{DIII-D}. This suggests that ORBIT-RF may be used to predictively model the interactions of rf-induced non-Maxwellian ion distribution with FW. To study the contributions of multiple poloidal modes, we will couple the full wave code AORSA to ORBIT-RF to evaluate rf-induced changes in perpendicular energy.