3D Modeling of RMP Erosion and Impurity Transport in L-Mode Discharges in the DIII-D Open Divertor using the ERO2.0 Code

The 3D kinetic Monte Carlo ERO2.0 code is used to model PWI and impurity transport for three L-mode discharges in the DIIID tokamak reconstructed with EMC3-EIRENE: (1) a no RMP reference, (2) 0-degree phasing, and (3) 60-degree phasing for n = 3. The discharges correspond to an open divertor configuration and (a) a fully carbon (C) target and (b) a tungsten (W) metal ring. A parameter scan for anomalous diffusion and starting carbon background concentrations show higher toroidally averaged net erosion for the no-RMP reference cases across all parameters, whereas the 60-degree RMP phasing performs best. Divertor surface maps show that particle re-erosion contributes to significant C deposition between the lobe structures, and their perimeter on the low-field side. Location tracing for C show radially outward particle trajectories along lobe structures. No full buildup of C is observed along the W ring cases for low concentrations of C in the background (<1%), with it occupying a maximum of ~15% of the ring surface concentration increasing the integrated C erosion as the mixing layer composition changes. This analysis can be used for H-Mode scenarios, experimental validation of tungsten erosion, and divertor studies considering the impact of RMP induced impurity transport.