How a stellarator works

Twisted superconducting coils shape a twisted plasma, so nothing has to be driven through the plasma itself and it can run steadily. Cool the coils, raise the field, start the plasma with microwaves and run the record six-minute pulse. Every number comes from one model.

Sources: Max Planck Institute for Plasma Physics, “Wendelstein 7-X sets new performance records” (June 2025: 1.8 GJ over 360 s, record triple product held 43 s, ions 20–30 million °C, 3% plasma pressure, ~90 pellets); IPP Wendelstein 7-X machine figures (5.5 m major radius, 0.53 m minor radius, 50 non-planar and 20 planar superconducting coils, up to 3 T, ~30 m³ plasma). The exact plasma and coil shapes and the day's pacing are illustrative. W7-X is a public research machine; the companies below are designing stellarator power plants on what it has shown. Others on this approach: Type One Energy, Thea Energy.