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 type	Stellarator
Location	Princeton, New Jersey, United States
Affiliation	Princeton Plasma Physics Laboratory
Technical specifications
Minor radius	5–7.5 cm (2.0–3.0 in)
Magnetic field	3.5 T (35,000 G)
History
Date(s) of construction	1961
Year(s) of operation	1962–1969
Preceded by	Model A/B stellarators[1]
Succeeded by	Symmetric Tokamak (ST)

Design parameters

The Model C had a racetrack shape. The total circumference of the magnetic axis was 12 m.^[2] 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.

Results

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

History

Construction funding/approval was announced in April 1957 with the design based on Katherine Weimer's efforts in fundamental research.^[3][4]

It started operating March 1962.^[5]

The Model C was reconfigured as a tokamak in 1969,^[1] becoming the Symmetric Tokamak (ST).^[6]

References

1. Stix, T. H. (1998). "Highlights in early stellarator research at Princeton" (PDF). J. Plasma Fusion Res. 1: 3–8.
2. Yoshikawa, S.; Stix, T.H. (1985-09-01). "Experiments on the Model C stellarator". Nuclear Fusion. 25 (9): 1275–1279. doi:10.1088/0029-5515/25/9/047. ISSN 0029-5515.
3. Princeton Alumni Weekly, Volume 57. April 19. p9
4. Johnson, John L.; Greene, John M. (September 2000). "Katherine Ella Mounce Weimer". Physics Today. 53 (9): 88. doi:10.1063/1.1325250. ISSN 0031-9228.
5. See 1962
6. See 1969,1970

Further reading

• 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.