Study of the impact of resonant magnetic perturbation fields on gross tungsten erosion using DiMES samples in DIII-D

An experiment was conducted in DIII-D to compare gross tungsten (W) erosion on samples exposed to outer strike point (OSP) sweeps in L-mode plasmas for three conditions. These included two phases of resonant magnetic perturbations (RMPs), and a set with no perturbations. Upon RMP application, lobe structures indicative of strike point splitting of the OSP were evident in divertor camera data and on Langmuir probes. Gross W erosion flux, ${\Gamma }_W,$ inferred spectroscopically using the S/XB method applied to the 400.9 nm W-I line, was generally in the range ${\Gamma }_W/{\Gamma }_{D+,\perp }=2\times {10}^{-4}$ referenced to incident deuterium ion flux ${\Gamma }_{D+,\perp },$ and was increased in the RMP cases by no more than 30% of the level observed in unperturbed discharges. A large reduction in gross erosion (50%) was observed in the private flux region at the W sample for one specific toroidal phase of the RMP field. (paper)