LAUSR

The inclusion of reduced-physics energetic particle (EP) transport models in the tokamak transport code TRANSP has resulted in a considerable improvement of interpretive and predictive capabilities for time-dependent simulations including the effects of EP transport by instabilities. The kick model has recovered the measured toroidal Alfvén eigenmode (TAE) spectrum on NSTX-U and DIII-D, and has reproduced details of the fast ion diagnostic data measured on DIII-D for EP-driven modes and tearing modes. Being able to predict the occurrence and effect of those instabilities is one of the grand challenges for fusion and a necessary step to mitigate their negative effects. The kick model has proven the potential of phase-space resolved EP simulations to unravel details of EP transport for detailed theory/experiment comparison and for scenario planning based on optimization of NBI parameters. Work is also ongoing to complement the kick model approach with the RBQ-1D model based on the resonance-broadened quasi-linear theory to develop a self-consistent, numerically efficient predictive EP transport model for integrated tokamak simulations. Both models are undergoing extensive verification and validation against analytical, numerical and experimental data to confirm their validity and identify potential applicability limitations.