A Short History of Fusion Energy

From 1950s tokamaks and mirrors to today's compact, high-field machines.

Fusion research began in earnest in the 1950s, splitting early into toroidal devices (the Soviet tokamak, stellarators) and open-ended magnetic mirrors. Tokamaks came to dominate after demonstrating superior confinement, and the field spent decades building ever-larger machines that steadily climbed the performance ladder.

Two developments reopened the compact path: high-temperature superconductors that reach fields once impossible, and cheap computation for design and validation. Kronos's architecture draws on both lineages — the tokamak for its breeder, the mirror for its burner.