United States · Magnetic confinement (compact tokamak)
SPARC
Operated by Commonwealth Fusion Systems · MIT PSFC · First operation 2027
Status: Under construction
Commonwealth Fusion's compact high-field tokamak designed to be the first device to achieve Q > 2 — and the prototype for the commercial ARC reactor.
SPARC uses high-temperature superconducting (HTS) REBCO magnets to reach 12.2 T — more than double conventional tokamaks — allowing a compact device to achieve net-energy fusion. First plasma targeted 2027; the design then scales to ARC, a 400 MWe commercial reactor.
Key specifications
- Major radius
- 1.85 m
- Magnetic field
- 12.2 T HTS
- Target Q
- >2 (sustained burning plasma)
- Fusion power
- ~140 MW
Milestones
Sep 2021
HTS magnet prototype hits 20 T, validates design
2023
Construction begins in Devens, MA
2027
Targeted first plasma