Commonwealth Fusion Systems Installs First SPARC Magnet, Eyes 2026 Plasma Milestone

Commonwealth Fusion Systems has installed TF1, the first of 18 high-temperature superconducting magnets, in the Tokamak Hall at its Devens, Massachusetts facility, marking the most tangible hardware milestone yet on the path to first plasma in 2026. The remaining 17 magnets are due to arrive on an approximately fortnightly basis over the coming months.

The numbers behind these magnets are serious. Each unit weighs 24 tonnes and will be cooled to -253°C (-423°F) so it can safely conduct over 30,000 amps of current. Their job is to contain plasma burning at more than 100 million degrees Celsius inside the toroidal vessel, and CFS designed them for a stronger magnetic field through a more compact, economical form factor rather than the sprawling footprints of earlier tokamak designs.

Alongside the hardware progress, CFS arrived at CES 2026 in Las Vegas on January 6 with a high-profile digital partnership in tow. CEO Bob Mumgaard joined Siemens CEO Roland Busch on stage to announce a three-way collaboration with Nvidia to build a digital twin of SPARC. Siemens is supplying design and manufacturing software to collect data from the Devens magnet factory floor and feed it into Nvidia's Omniverse libraries, where AI and simulation technology will host the virtual model.

Mumgaard was direct about what changes with this approach. "These are no longer isolated simulations that are just used for design," he said. "They'll be alongside the physical thing the whole way through, and we'll be constantly comparing them to each other." The goal is to run experiments and tweak parameters in the digital twin before touching SPARC itself: "It will run alongside so we can learn from the machine even faster."

CFS also works with Google DeepMind AI systems alongside the Nvidia collaboration, and the company uses a pointed analogy to explain the division of labor: DeepMind is the co-pilot, the Nvidia digital twin is the virtual airplane.

Del Costy, president and managing director of the Americas for Siemens Digital Industries Software, framed the manufacturing side of the collaboration in characteristically direct terms. "Fusion is complex, but data doesn't lie," Costy said. "When you aggregate real manufacturing intelligence, apply AI, and run thousands of scenarios, you remove guesswork and accelerate innovation. This is the future of industrial engineering."

Busch made the commercial case from the stage at CES: "AI factories and data centers require gigawatts of electric power. What if we had an energy source that was clean, safe, affordable, and practically limitless?"

On timeline, CFS has set first plasma as a 2026 target, though the company has previously noted that SPARC could begin producing energy sometime after this year, a slightly more cautious framing. Either way, the fortnightly magnet delivery schedule means the machine will be substantially populated well before any plasma attempt. SPARC is itself a stepping stone: CFS plans to follow it with ARC, a grid-scale commercial device targeted for the early 2030s.

The IEA has noted that fusion is advancing rapidly but that further technology innovation is still needed to address near-term challenges at the MW-pilot scale. CFS, with 18 magnets now queued up and a digital twin running in parallel, is staking its answer to that challenge on the convergence of physical hardware and AI-driven simulation.