Researchers at the University of Wisconsin set a world record by sustaining plasma with a 17‑tesla magnetic field using high‑temperature superconducting magnets, revitalizing the compact magnetic mirror fusion concept. The magnets were supplied by Commonwealth Fusion Systems and the project is supported by Realta Fusion. Proponents say fusion could deliver large amounts of carbon‑free energy—one gram of fuel can be compared to roughly 11 tons of coal in energy terms—but experts warn commercial fusion is still many years away. International partnerships and diverse technical approaches continue to advance the field.
UW Team Sets 17‑Tesla Magnetic Containment Record, Revives Compact 'Magnetic Mirror' Fusion Approach
Researchers at the University of Wisconsin set a world record by sustaining plasma with a 17‑tesla magnetic field using high‑temperature superconducting magnets, revitalizing the compact magnetic mirror fusion concept. The magnets were supplied by Commonwealth Fusion Systems and the project is supported by Realta Fusion. Proponents say fusion could deliver large amounts of carbon‑free energy—one gram of fuel can be compared to roughly 11 tons of coal in energy terms—but experts warn commercial fusion is still many years away. International partnerships and diverse technical approaches continue to advance the field.
05:52 PM, 11/17/2025Science
Researchers achieve a 17‑tesla magnetic confinement milestone
Researchers at the University of Wisconsin have set a new world record for magnetic field strength in a magnetically confined plasma experiment by sustaining plasma using high‑temperature superconductor (HTS) magnets that reached 17 tesla. The magnet systems were delivered this year by Commonwealth Fusion Systems to the university's Physical Sciences Laboratory in Stoughton, Wisconsin, and the effort is run as a public–private collaboration supported by Realta Fusion, a UW–Madison spin‑off.
The work updates a classic fusion architecture known as the magnetic mirror. Once a leading approach through the 1980s, the magnetic mirror concept has been modernized here by pairing it with powerful HTS magnets that trap energetic plasma in a so‑called magnetic bottle. The apparatus also includes intense heating systems and remains a hands‑on platform for both graduate and undergraduate students.
Jay Anderson, Realta Fusion co‑founder and UW–Madison scientist, said the experiment 'is setting a world record in magnetic field strength for magnetically confined plasmas' and highlighted its educational role.
Fusion power is produced when light atomic nuclei combine to form a heavier nucleus. The small difference in mass is released as energy according to E=mc², the same fundamental process that powers the sun. Proponents note that, in principle, a tiny amount of fusion fuel could deliver an enormous amount of energy; estimates often compare one gram of fusion fuel to roughly the energy content of about 11 tons of coal, without direct carbon dioxide emissions.
German–American scientist and entrepreneur Frank Laukien has argued that fusion should become a third pillar alongside solar and wind for a fully renewable energy supply, calling it 'the key to a decarbonized future.' Realta Fusion CEO Kieran Furlong added that the demonstration 'puts the compact magnetic mirror firmly back in the race towards commercial fusion energy' and called it 'a giant leap forward' for a concept that could provide economically viable, zero‑carbon heat and electricity.
Governments and industry are taking note: the United States and Japan announced a partnership to accelerate fusion development and commercialization, and the field continues to explore various approaches — including some that do not rely on conventional magnet‑and‑laser configurations.
Outlook and caveats: While this record is a meaningful technical milestone, experts emphasize that commercial, grid‑scale fusion remains many years away. In the nearer term, expanding proven renewables such as wind and solar is essential for decarbonization while fusion research continues.