ELM flushing and impurity transport in the H-mode edge barrier in ASDEX Upgrade

Density proles of He 2+ , C 6+ , Ne 10+ and Ar 16+ are measured at ASDEX Upgrade with high temporal (1:9 ms) and radial resolution (> 3 mm) using CXRS. This allows the transport coefcients at the edge transport barrier to be analyzed in between type-I ELMs during H-mode. All measurements resemble the neoclassical transport coefcients, which means that the diffusion coefcient ranges from 0.15-0.35 m 2 /s and the maximum of the inward convection velocity is Z-dependent increasing from 15 m/s (He 2+ ) to 90 m/s (Ar 16+ ). These results are combined into a simplied transport-erosion model for W which calculates the neoclassical transport coefcients self-consistently while taking several impurity species into account. The model also calculates erosion ux es at the wall, prompt redeposition of W and loss terms due to parallel o ws in the scrape-off layer. While several free parameters exist in the the model, it demonstrates that a quantitative consistency between the measured erosion ux es of W and the observed W concentration inside the plasma is obtainable.