Large wetted areas of divertor power loads at Wendelstein 7-X

Wendelstein 7-X(W7-X), an optimized stellarator, conducted its first divertor operation. It uses an island divertor concept for the heat and particle exhaust. Large wetted areas of up to 1.5 m2 have been reached, showing the benefits of the divertor concept and very efficient heat flux spreading. Moreover, a positive scaling of the wetted area with increasing SOL power is observed, which is important for operations at high input power. A definition of the wetted area is made based on thermographic camera observations for the 3D structure of W7-X with comparability to the definitions of other machines (e.g. tokamaks).