Developing and Applying a Self-Consistent Model of Coupled Pedestal, Scrape-Off-Layer, and Divertor Physics

A self-consistent, predictive model for the edge plasma from the top of the pedestal to the divertor has been developed, and initial tests have been conducted. The model uses the IPS-CESOL framework to integrate an updated version of the EPED pedestal model with the SOLPS-ITER scrape-off-layer (SOL) and divertor code. In the coupled model, EPED predicts profiles in the pedestal region, using boundary conditions at the separatrix provided by SOLPS, while SOLPS predicts SOL and divertor conditions, and sources throughout the domain. The SOL width is calculated using either an empirical model or a physics model based on near-separatrix ballooning criticality. Initial tests on existing devices find that the coupled model predicts strong pedestal degradation due to high gas puffing to produce divertor detachment, in agreement with observation. However, for strongly shaped plasmas at higher field, the coupled model predicts that the pedestal remains limited by peeling modes (and in some cases can access the Super H-Mode regime) even at high pedestal density, and predicted pedestal performance increases substantially. Predictions for ITER and other future devices, as well as initial coupling to TGLF and optimization studies of a compact pilot plant are planned.