Stellarator profile predictions using Trinity3D and GX

We present stellarator transport calculations using a first-principles gyrokinetic approach, based on a new multi-scale transport framework composed of the Trinity3D transport solver and the GX gyrokinetic code. GX computes the full nonlinear turbulent fluxes from the gyrokinetic equations, using a pseudo-spectral formulation. Trinity3D leverages an implicit time step to model transport scale evolution from micro turbulent scale fluxes. It recomputes the equilibria by using self-consistent profiles in VMEC. Our model includes alpha heating, collisional equilibration between species, and bremsstrahlung radiation. Since Trinity solves the time dependent power balance equation, it is also possible to introduce time dependent sources, for example experimental auxiliary heating. We will present our attempt to explain the ion-clamping phenomena observed experimentally in W7X, and how it is alleviated by peaking the density profile. We will also present simulations of a hypothetical stellarator reactor heated to ignition.