English: Schematic diagram of the superconducting stellarator Wendelstein 7-X. The last closed magnetic flux surface is indicated in magenta. The plasma vessel is shaped according to the magnetic field geometry. The 50 non-planar coils have an aluminum foil plated steel casing, the 20 planar coils a copper plated steel casing. The non-planar and the planar coils of each type are connected in series via superconducting bus bars. Coils, coil casings and the central support ring are supplied with liquid helium by means of a pipe system. The magnet system is operated in the vacuated cryostat volume between the plasma vessel and the outer vessel.