Progress in coupling a transport solver to global gyrokinetic simulations

Predictive modeling with transport solvers has tended to use surrogate models, such as quasilinear transport models, to represent turbulent fluxes. One route to improved predictive modeling is instead to couple with direct numerical simulations (DNS) of gyrokinetic turbulence. We have coupled the transport code Tango to the gyrokinetic code GENE. The first results used global gyrokinetic simulations with adiabatic electrons in a circular magnetic geometry, and the transport solver evolved ion pressure. Here, we report on progress in using a DIII-D-like geometry. We also report on progress using kinetic electrons and evolving ion pressure, electron pressure, and density. An additional complication of coupling a transport solver to turbulence simulations rather than a surrogate model is that the fluctuations hinder convergence, and we analyze this issue.