UEDGE simulation of detached divertor operation in DIII-D with a chemically sputtered carbon source

摘要

We describe the response of the scrape-off layer (SOL) plasma to variations in the intensity, and geometry of an intrinsic carbon source in DIII-D. Using the multi species 2-D fluid plasma code UEDGE we find plasma modes which are similar to those seen experimentally. At high sputtering coefficient the plasma discontinuously transitions to a state in which the radiation power exceeds the input power and no steady state solution is obtained. We believe this corresponds to the MARFE (Multifaceted Asymmetric Radiation from Edge) state seen experimentally, in which the core confinement is reduced.