  This work presents the PORTALS framework, which leverages surrogate modeling
and optimization techniques to enable the prediction of core plasma profiles
and performance with nonlinear gyrokinetic simulations at significantly reduced
cost, with no loss of accuracy. The efficiency of PORTALS is benchmarked
against standard methods, and its full potential is demonstrated on a unique,
simultaneous 5-channel (electron temperature, ion temperature, electron
density, impurity density and angular rotation) prediction of steady-state
profiles in a DIII-D ITER Similar Shape plasma with GPU-accelerated, nonlinear
CGYRO. This paper also provides general guidelines for accurate performance
predictions in burning plasmas and the impact of transport modeling in fusion
pilot plants studies.
