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Fusion energy: Progress, partnerships, and the path to deployment
Over the past decade, fusion energy has moved decisively from scientific aspiration toward a credible pathway to a new energy technology. Thanks to long-term federal support, we have significantly advanced our fundamental understanding of plasma physics—the behavior of the superheated gases at the heart of fusion devices. This knowledge will enable the creation and control of fusion fuel under conditions required for future power plants. Our progress is exemplified by breakthroughs at the National Ignition Facility and the Joint European Torus.
G. J. Hartwell, S. F. Knowlton, J. D. Hanson, D. A. Ennis, D. A. Maurer
Fusion Science and Technology | Volume 72 | Number 1 | July 2017 | Pages 76-90
Technical Paper | doi.org/10.1080/15361055.2017.1291046
Articles are hosted by Taylor and Francis Online.
The Compact Toroidal Hybrid (CTH) is a low-aspect-ratio (), low-beta (%) torsatron with a major radius of . CTH is operable as a pure stellarator, but most research on this device is conducted with hybrid discharges in which a toroidal plasma current is driven in order to study magnetohydrodynamic instabilities and disruptions in current-carrying stellarator plasmas. The vacuum helical field of CTH is produced by a continuously wound helical coil with poloidal and toroidal periodicities of and , respectively. The maximum on-axis toroid al magnetic field is . The helical coil encloses a circular vacuum vessel of major radius = 0.75 m with a circular cross section of minor radius 0.29 m. A toroidal plasma current up to 80 kA is produced with an ohmic heating (OH) transformer. The average plasma radius is typically 0.20 m. Five independently controllable magnet coil sets produce the base stellarator magnetic field configuration. With 15-kW electro.n cyclotron heating at the fundamental frequency, densities of and electron temperatures of 20 eV are achieved. With the addition of OH, densities reach with temperatures of . Ten motor/generator power supplies provide up to 10 MW of power to energize the magnet set providing the equilibrium field, and a capacitor bank provides the pulsed current for the OH system. Design considerations, constraints, and construction techniques of the CTH magnet coils, vacuum vessel, and support structure are discussed, and an operational overview is given.