Core to Edge Variation of Multiscale Turbulent Transport in ITER Baseline Discharges at DIII-D

High fidelity gyrokinetic simulations and dedicated experiments that measured the heat and impurity transport from r/a = 0.5 to 0.9 in reactor relevant, ITER baseline discharges find compelling evidence of multi-scale turbulence. Ion-scale (ITG/TEM), electron-scale (ETG), and multiscale (coupled ion and electron-scale) simulations have been used to probe the radial variation of cross-scale coupling and its role in setting experimental levels of transport. Validation quality profile and fluctuation data (BES, DBS, & PCI) were collected in conditions predicted to exhibit measurable characteristics of cross-scale coupling in intermediate scale density fluctuations (k$_\theta$ $\rho_s$ $\sim$ 3.0). Over 70 nonlinear CGYRO simulations were performed to study ion and electron-scale turbulence and probe the sensitivity of results within experimental uncertainty at 5 radial locations. The simulations were compared directly with experimental heat transport levels, low and intermediate-k density fluctuations, and predicted trace impurity transport (D and V) across the profile. Simulated ion-scale turbulence reproduces experimental ion heat flux levels but under-predicts electron heat flux in many radial locations, pointing to a likely role of electron and multi-scale turbulence. To confirm the multiscale nature of the turbulence and validate the gyrokinetic model, cutting-edge simulation was performed at r/a = 0.7 on the Titan Supercomputer that spans ion and electron scales (up to k$_\theta$ $\rho_s$ = 54.0) with unprecedented physics fidelity (E&M turbulence, realistic electron mass, rotation effects, collisions, all experimental inputs). The presented comparisons of ion, electron, and multi-scale simulation with experimental fluxes & fluctuations reveal the physical mechanisms dictating radial variation of heat and particle transport in reactor-relevant conditions.