  The energetic electrons (EEs) generated through auxiliary heating have been
found to destabilize various Alfven eigenmodes (AEs) in recent experiments,
which in turn lead to the EE transport and degrade the plasma energy
confinement. In this work, we propose a global fluid-kinetic hybrid model for
studying corresponding kinetic-magnetohydrodynamic (MHD) processes by coupling
the drift-kinetic EEs to the Landau-fluid model of bulk plasmas in a
non-perturbative manner. The numerical capability of Landau-fluid bulk plasmas
is obtained based on a well-benchmarked eigenvalue code MAS [Multiscale
Analysis of plasma Stabilities, J. Bao et al. Nucl. Fusion accepted 2023], and
the EE responses to the electromagnetic fluctuations are analytically derived,
which not only contribute to the MHD interchange drive and parallel current but
also lead to the newly kinetic particle compression with the precessional drift
resonance in the leading order. The hybrid model is casted into a nonlinear
eigenvalue matrix equation and solved iteratively using Newton's method. By
calibrating the EE precession frequency against the particle equation of motion
in general geometry and applying more realistic trapped particle distribution
in the poloidal plane, MAS simulations of EE-driven beta-induced Alfven
eigenmodes (e-BAE) show excellent agreements with gyrokinetic particle-in-cell
simulations, and the non-perturbative effects of EEs on e-BAE mode structure,
growth rate and damping rate are demonstrated. With these efforts, the upgraded
MAS greatly improves the computation efficiency for plasma problems related to
deeply-trapped EEs, which is superior than initial-value simulations restricted
by the stringent electron Courant condition regarding to the practical
application of fast linear analysis.
