Lyman Spitzer, Jr., a professor of Astronomy at Princeton University, had for many years been involved in the study of very hot rarefied gases in interstellar space. He was inspired by the fascinating, but erroneous claims of controlled nuclear fusion achieved in Argentina by Ronald Richter, Spitzer. In 1950, he conceived of a plasma being confined in a figure-eight-shaped tube by an externally generated magnetic field, where the ionized hydrogen gas would fuse into helium, releasing energy for the production of power. He called this concept the stellarator, and took this design before the Atomic Energy Commission in Washington. As a result of this meeting and a review of the invention by designated scientists throughout the nation, the stellarator proposal was funded in 1951 as Project Matterhorn. In 1958, this magnetic fusion research was declassified following the 1955 United Nations International Conference on the Peaceful Uses of Atomic Energy. This generated an influx of graduate students eager to learn the "new" physics, which in turn influenced the lab to concentrate more on basic research.
The early figure-8 stellarators included : Model-A, Model-B, Model-B2, Model-B3. Model-B64 was a square with round corners, and Model-B65 was a racetrack configuration. The last and most powerful stellarator at this time was the 'racetrack' Model C (operating from 1961-69). The Model C was reconfigured as a tokamak in 1969, becoming the Symmetric Tokamak (ST).
In the 1970s research at the PPPL refocused on the Russian tokamak design when it became evident that it was a more satisfactory containment design than the stellarator. In May 1972 the Adiabatic Toroidal Compressor (ATC) began operation. The Princeton Large Torus, a tokamak, operated from 1975.
In 1999, the National Spherical Torus Experiment (NSTX), based on the spherical tokamak concept, came online at the PPPL. Laboratory scientists are collaborating with researchers on fusion science and technology at other facilities, both domestic and foreign. Staff are applying knowledge gained in fusion research to a number of theoretical and experimental areas including materials science, solar physics, chemistry, and manufacturing.