Model C stellarator

The Model C stellarator was the first large-scale stellarator to be built, during the early stages of fusion power research. Planned since 1952, construction began in 1961 at what is today the Princeton Plasma Physics Laboratory (PPPL).[1] The Model C followed the table-top sized Model A, and a series of Model B machines that refined the stellarator concept and provided the basis for the Model C, which intended to reach break-even conditions. Model C ultimately failed to reach this goal, producing electron temperatures of 400 eV when about 100,000 were needed. In 1969, after UK researchers confirmed that the USSR's T-3 tokamak was reaching 1000 eV, the Model C was converted to the Symmetrical Tokamak, and stellarator development at PPPL ended.

Model C stellarator
Device TypeStellarator
LocationPrinceton, New Jersey, United States
AffiliationPrinceton Plasma Physics Laboratory
Technical specifications
Minor Radius5–7.5 m (16–25 ft)
Magnetic field3.5 T (35,000 G)
Date(s) of construction1961
Year(s) of operation1962 – 1969
Preceded byModel A/B stellarators[1]
Succeeded bySymmetric Tokamak (ST)

Design parametersEdit

The Model C had a racetrack shape. The total length (of the tube axis?) was 1.2m. The plasma could have a 5-7.5 cm minor radius. Magnetic coils could produce a toroidal field (along the tube) of 35,000 Gauss.[1] It was only capable of pulsed operation.

It had a divertor in one of the straight sections. In the other it could inject 4 MW of 25 MHz ion cyclotron resonance heating (ICRH).

It had helical windings on the curved sections.


An average ion temperature of 400 eV was reached in 1969.


Construction funding/approval was announced in April 1957.[2]

Starts operating March 1962.[3]

The Model C was reconfigured as a tokamak in 1969,[1] becoming the Symmetric Tokamak (ST).[4]


  1. ^ a b c d Stix, T. H. (1998). "Highlights in early stellarator research at Princeton" (PDF). J. Plasma Fusion Res. 1: 3–8.
  2. ^ Princeton Alumni Weekly, Volume 57. April 19. p9
  3. ^ See 1962
  4. ^ See 1969,1970

Further readingEdit