Wendelstein 7-X is the world’s largest fusion device of the stellarator type. Its objective is to investigate the suitability of this type for a power plant. It will test an optimised magnetic field for confining the plasma, which will be produced by a system of 50 non-planar and superconducting magnet coils, this being the technical core piece of the device. It is expected that plasma equilibrium and confinement will be of a quality comparable to that of a tokamak of the same size. But it will avoid the disadvantages of a large current flowing in a tokamak plasma: With plasma discharges lasting up to 30 minutes, Wendelstein 7-X is to demonstrate the essential stellarator property, viz. continuous operation.
The main assembly of Wendelstein 7-X was concluded in 2014, the first plasma was produced on 10th December 2015.