The High-Field-Tokamak Path to Fusion Energy: Alcator to SPARC to ARC†
Earl Marmar, Plasma Science and Fusion Center, Massachusetts Institute of Technology
This presentation will review the physics and technology basis of a path to realizing fusion energy using the compact, high-magnetic-field tokamak approach. Innovations underway include increasing energy and particle confinement; improving transport barriers; maximizing the functionality of heating and current drive; effectively exhausting the extreme heat and particle fluxes in the boundary plasma; and controlling and optimizing (1) fusion-output-power handling, (2) the removal of helium ash from cooled alpha particles, and (3) non-hydrogen/non-helium impurities. With conservative assumptions about energy confinement, a pre-conceptual design has been developed for a net energy gain facility, SPARC (major radius R=1.65m, toroidal magnetic field BT=12T), using hightemperature, high-critical-magnetic-field superconducting magnets. Extrapolation to a larger, slightly lower-field (R=3.3m, BT =9.2T), steady-state pilot plant design, ARC [1,2], is projected to produce 500 MW of fusion power and would put a new electricity source on the grid. The extrapolations to SPARC and ARC rely heavily on the high-field results from Alcator C-Mod. Possible technology advantages of the high-temperature superconductors, including development of jointed coils for configuration flexibility and facility maintainability, will also be discussed.
 B.N. Sorbom, et al., Fus. Eng. Des. 100(2015)378.
 A.Q. Kuang, et al., Fus. Eng. Des. (2019) in press.
†This work supported by US DOE and Commonwealth Fusion Systems.