Application of an empirical saturation rule to TGLF to unify low-k and high-k turbulence dominated regimes

Abstract

We propose a phenomenological turbulence saturation model and apply it to the TGLF turbulence transport model (Staebler et al 2007 Phys. Plasmas 14 055909), which captures the physics of interaction between low-k and high-k turbulence consistent with the multi-scale gyro-kinetic simulation result reported by Howard (2016 Nucl. Fusion. 23 056109). The new model, TGLF-Vx is tested with three discharges from DIII-D and EAST tokamak, which cover both low-k and high-k turbulence dominated regimes. It is found that the profile match can be substantially improved over previous models when evolving Te, Ti and ne simultaneously. Good agreement for all three discharges is obtained with one fixed parameter in the model when taking experimental uncertainties into consideration. Lastly, TGLF-Vx is applied to explore the sensitivity of the predicted CFETR steady-state performance to different transport models. Our result shows that a scenario using only RF auxiliary heating could be significantly affected.