First operational phase of the superconducting magnet system of Wendelstein 7-X

The Wendelstein 7-X stellarator (W7-X), one of the largest stellarator fusion experiments, has accomplished successfully the first operational phase at the Max Planck Institute for Plasma Physics in Greifswald, Germany. To confine 30 m3 plasma the W7-X machine has a superconducting magnet system with 50 non-planar and 20 planar coils. The magnet commissioning was successfully performed until mid of 2015 with tests of the complete magnet system functionality required for plasma operation, at a magnetic field of 2.5 T. The first operational phase started mid of December 2015 with He plasmas heated by the ECRH (Electron Cyclotron Resonance Heating) system followed by H2 plasmas in February 2016. The magnet system operation was accompanied by an online monitoring of the mechanical sensors installed on the superconducting coils and their support structure to detect any deviations from the predicted behavior.