After a series of smaller devices from 1960 onwards Wendelstein 7-A, IPP’s first large stellarator, went into operation in 1975.
Its magnetic field was generated by 40 planar coils installed around the plasma vessel. This was accompanied by helical current leads wound right on the plasma vessel, these serving to twist the magnetic field lines.
Wendelstein 7-A gave a major boost to the stellarator line. In 1980 the device was able to demonstrate with a hot plasma for the first time in the world the “pure” stellarator principle, i.e. confinement without plasma current.