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 cm (2.0–3.0 in)
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 with the design based on Katherine Weimer's efforts in fundamental research.[2][3]

It started operating March 1962.[4]

The Model C was reconfigured as a tokamak in 1969,[1] becoming the Symmetric Tokamak (ST).[5]


  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. ^ Johnson, John L.; Greene, John M. (September 2000). "Katherine Ella Mounce Weimer". Physics Today. 53 (9): 88–88. doi:10.1063/1.1325250. ISSN 0031-9228.
  4. ^ See 1962
  5. ^ See 1969,1970

Further readingEdit

  • Experiments on the Model C stellarator. S. Yoshikawa and T.H. Stix
  • A CONCEPTUAL DESIGN OF THE MODEL C STELLARATOR. 1956 Says 9" vacuum tube, but 150 ft long seems unlikely. 150,000 kW peak of pulsed power to the magnets.