Optimisation of target plates for the W7-X divertor at stationary operation

The open divertor structure of the Wendelstein 7-X stellarator allows an effective particle and energy exhaust for a wide range of plasma and magnetic parameters. Ten 3D-shaped surfaces are located along the helical edge of the five-fold rotational symmetry magnetic configuration of the machine. The plasma outflow concentrates onto the target plates, so that the plasma is decoupled from the wall. The target plates are designed to withstand a maximum stationary heat flux of 10 MW/m2. The present optimised design of the target plates, which takes into account the latest results of the physics, the requirements of the heatings and diagnostics systems, the manufacturing costs and the mounting operations in order to build a technical reliable system is presented.