Gyrokinetic-MHD Hybrid Simulation of Energetic-Particle-Driven Toroidal Alfvén Eigenmodes with Radiative Damping in High-βp EAST Plasmas

Abstract The linear stability of energetic particle (EP) driven toroidal Alfvén eigenmodes (TAEs) in EAST high-β p plasmas is numerically investigated using the gyrokinetic MHD hybrid initial value code GMEC. The analysis focuses on an experimentally observed n = 3 TAE in an ion-cyclotron-resonance-heated discharge. The simulated unstable mode has a frequency of 145.3 kHz, in agreement with the measured value of approximately 145 kHz. The radiative damping rate is -γ d /ω = 1.8%, close to the analytical estimate. A systematic variation of EP-related parameters shows that increasing the EP beta primarily enhances the energetic-particle drive, while the birth energy and pitch-angle anisotropy modify the mode structure, excitation threshold, and the transition between EPM-like and TAE-like branches. Changes in the safety factor profile, local magnetic shear, and plasma shaping further modify the Alfvén continuum structure and the background damping. These results show that both EP phase space properties and equilibrium geometry are important for assessing TAE stability in EAST high βp plasmas.