Radiative power exhaust with impurity seeding at Wendelstein 7-X

First radiative power exhaust experiments with impurity seeding have been conducted in the 3D island divertor at W7-X. Ne seeding showed substantial enhancement of 𝑃𝑟𝑎𝑑 by up to 40% in plasma scenarios with 𝑛𝑒≈1−2×1019m−3 and ECRH heating of 2.5-5MW accompanied by a drop of divertor peak heat fluxes from 𝑞𝑑𝑖𝑣, 𝑚𝑎𝑥≈2MWm−2 to 1MWm−2. 𝑃𝑟𝑎𝑑 decays over seconds after termination of Ne injection. N2 seeding results in weaker 𝑃𝑟𝑎𝑑 enhancement and fast recovery of divertor heat fluxes and SOL electron temperatures measured with the He beam in the seeded island. The effects of seeding on heat and particle fluxes will be analyzed. The impact of changes of the island geometry on 𝑃𝑟𝑎𝑑 will be discussed based on 3D transport calculations with EMC3-EIRENE and particle balance analysis.