Speaker: Thomas Klinger, Max-Planck-Institut für Plasmaphysik and Greifswald University
Abstract: Stellarators are disruption-free and inherently capable to operate in steady-state. The optimized superconducting stellarator device Wendelstein 7-X (major radius 5.5 m, minor radius 0.5 m, 30m3 plasma volume) restarted operation after the assembly of a graphite heat shield and 10 inertially cooled island divertor modules. With 2.5 T magnetic field on axis and 8 MW micro wave heating power, high performance divertor plasmas are generated that allow one to establish the scientific basis for the extrapolation to a next step device. Wendelstein 7-X was designed for steady-state high-power operation, more specifically for 1800 s at 10 MW input power. This talk summarizes the physics results obtained during the recent first operation phases, notably high density and performance discharges, stellarator physics optimization, and island divertor operation. We also discuss the key physics subjects for optimized stellarators and briefly review the construction of such a first-of-a-kind device.