Nonlinear Hybrid Simulation of the Toroidicity-Induced Alfvén Eigenmode

Gyrokinetic-magnetohydrodynamic hybrid simulations have been carried out to study the nonlinear saturation of the torodicity-induced Alfvén eigenmode driven by energetic particles in a tokamak plasma. It is shown that wave-particle trapping is the nonlinear saturation mechanism for the parameters considered. The corresponding density profile flattening of the hot particles is observed. The saturation amplitude is proportional to the square of the linear growth rate. In addition, a new $n=1,m=0\mathrm{}$ global Alfvén eigenmode is shown to be excited by the energetic particles.