Skip to content

Commonwealth Fusion Systems creates viable path to commercial fusion power with world’s strongest magnet

Cambridge, Mass. - September 8, 2021Commonwealth Fusion Systems (CFS) and MIT’s Plasma Science and Fusion Center (PSFC) today announced the successful test of the world’s strongest high temperature superconducting (HTS) magnet, the key technology for a device that will unlock the path to clean commercial fusion energy for the world.

The milestone test, conducted at MIT’s Plasma Science and Fusion Center, proved that the magnet built at scale can reach a sustained magnetic field of more than 20 tesla, enough to enable CFS’s compact tokamak device, called SPARC, to achieve net energy from fusion, a historic first.

“This record-breaking magnet is the culmination of the last three years of work and will give the world a clear path to fusion power for the first time,” said Bob Mumgaard, CFS CEO. “The world needs a fundamentally new technology that will support efforts to decarbonize on a timeline that can mitigate climate change. This test of our magnet proves we have that technology, and we’re on our way to producing clean, limitless energy for the entire world.”

CFS and MIT’s PSFC used new commercially available high temperature superconductors (HTS) to build the magnets that will enable significantly stronger magnetic fields in a fusion device called a tokamak. While existing tokamaks rely on device scale to attempt net energy, HTS magnets enable a high-field approach that will enable CFS to reach net energy from fusion with a device that is substantially smaller, lower cost, and on a faster timeline.

“This groundbreaking magnet opens a widely identified transformational and accelerated opportunity for advancing fusion science and commercial fusion energy,” said Dennis Whyte, Director of MIT’s PSFC and CFS Co-Founder.

Tokamaks are donut-shaped devices that use magnets to control and insulate a plasma in which fusion occurs. While no fusion device has yet to achieve net energy from fusion, tokamaks have come the closest with more than 160 tokamaks built and successfully operated around the world. In the past, tokamaks used low-temperature superconducting magnets that required them to be enormous in size to create the magnetic field needed to attempt to achieve net energy. CFS HTS magnets will enable significantly stronger magnetic fields and as a result significantly smaller tokamaks. Fusion power plants will have advantages over traditional power plants as they will be carbon-free, dispatchable, have limitless fuel supply, and are inherently safer than other types of plants.  

This HTS magnet technology will next be used in SPARC, which is under construction in Devens, Massachusetts and on track to demonstrate net energy from fusion by 2025. SPARC will pave the way for the first commercially viable fusion power plant called ARC. “This is the fastest path to commercialization of affordable fusion energy across the globe,” explains Mumgaard.


 About CFS

CFS is on track to bring fusion energy technology to market. CFS was spun out of MIT and combines the decades of research experience of MIT’s Plasma Science and Fusion Center with the innovation and speed of the private sector. Supported by the world’s leading investors in breakthrough energy technologies, CFS is uniquely positioned to deliver the fastest path to commercial fusion energy.


Supporting Assets:      

MIT Release:


Magnet animation: