Energy · 1951

Stellarator

Twisted magnetic fields try to confine a fusion plasma.

Lyman Spitzer proposed the figure-eight stellarator at Princeton in 1951 and the first devices ran soon after. Germany's Wendelstein 7-X, first plasma in 2015, revived the design with computer-optimized coils.

See it in the living tree Wikipedia

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 2

Quantum mechanics 1925
Special relativity 1905

What it led to 1

Tokamak 1958

Watch

Wendelstein 7-X fusion device – visualized from construction dataMax-Planck-Institut für Plasmaphysik · YouTube

Related measurements

The dashed line marks when it first worked.

Record fusion triple product Latest: 1.73×10²² keV·s/m³ (2017) Source: Wurzel & Hsu 2022, Physics of Plasmas 29, 062103; Wurzel & Hsu 2025 update, Physics of Plasmas 32, 112106

Nuclear electricity generation Latest: 2.81k TWh (2025) Source: Our World in Data