Progress in Integration of Critical Gradient Fast Ion Transport Modeling

A major challenge for the core plasma of a sustained, high power density advanced tokamak reactor is the self-consistent ability to reach both high self-generated "bootstrap" current (to reduce auxiliary or inductive current drive needs) and high pressure (to produce enough fusion power). In past DIII-D 'high qmin' experiments, Alfvén Eigenmode (AE) induced fast-ion transport has limited performance. In this work, we build upon recent success with using the TGLF-EP+Alpha fast-ion transport model to calculate AE-induced changes to neutral beam power fluxes, leading to more accurate TGYRO/TGLF thermal profile predictions. The TGLF-EP+Alpha model is implemented in time-dependent modeling workflows to better predict electron, ion temperature profiles and current evolution. The model is applied to high qmin scenario experiment planning to determine the effects of increased density and non-neutral beam heating and current drive, such as DIII-D's new microwave and RF sources. This approach is expected to reduce fast-ion stored energy fraction and reduce AE instability in order to move towards more classical fast-ion transport conditions to reach high performance and high bootstrap fraction.