Wendelstein 7-X is an experimental stellarator device built in Greifswald, Germany, at the Max Planck Institute of Plasma Physics, and completed in October 2015. It is based on a five field-period Helias configuration. It is mainly a toroid, consisting of 50 non-planar and 20 planar superconducting magnetic coils, 3.5 m high. The 50 non-planar coils …

TJ-II is a flexible heliac installed at the National Fusion Laboratory in Spain. Its first plasma run was in 1997, and as of 2022 is still operational. It is a four period low magnetic shear stellarator with major radius R = 1.5 m, average minor radius a < 0.22 m, and magnetic field on axis …

Plasma rotation has become one of the key ingredients of fusion plasma performance, specially after the discovery of a reduction of turbulence and transport through a sheared E × B rotation. With regard to stability, large toroidal rotation can stabilize resistive wall modes and neoclassical tearing modes. For these reasons, the physics of toroidal momentum …

In magnetic confinement fusion, atomic species other than the fusion reactants (e.g. deuterium and tritium for the fuel mix envisaged for the first demonstration reactors) are termed ‘impurities’. The presence of even small concentration of impurities (especially those of high charge number Z ) in the confinement volume has deleterious consequences on plasma performance, due …