BANG! Nuclear Fusion Test Achieves Unprecedented Milestone in Magnet Power

A significant achievement in nuclear fusion was attained at the University of Wisconsin-Madison, where researchers achieved a new milestone by creating the most powerful constant magnetic field to date for plasma confinement. This development injects fresh optimism into the feasibility of future reactors that aim to generate more energy than they consume.

This breakthrough involved state-of-the-art magnets supplied by Commonwealth Fusion Systems (CFS), a leader in the fusion sector, to UW-Madison’s WHAM project recently. The WHAM team managed to initiate operation of these magnets at the required low temperatures, activating them with a potent electrical current. This action achieved a magnetic field of 17 tesla, significantly outperforming the magnetic fields utilized by the most advanced MRI scanners for brain imaging, by more than a factor of two.

The role of powerful magnets is crucial in the fusion power generation method championed by CFS and its peers. It is established that with each doubling of magnetic field strength, the energy yield from a specific reactor design can increase exponentially, by a factor of 16.

Although WHAM has been operational for several years, “it was the first time plasma was confined using these advanced magnets,” remarked Kieran Furlong, who is at the helm of Realta Fusion, a company that evolved from WHAM in 2022 and maintains a strong collaboration with the UW-Madison team and the experiment.

The prior record for magnetic confinement was held by MIT’s Alcator C, according to Furlong.

This milestone with WHAM’s magnetic field exemplifies the tight-knit nature of the fusion research community, building upon the foundational work done on the Alcator C and its successor, Alcator C-Mod, which laid the groundwork for CFS’s reactor and magnet technology.

Launched by MIT in 2018, CFS was created to commercialize fusion energy through innovative magnet technology. CFS, along with Realta, is pioneering the development of reactors that utilize robust magnetic fields to maintain plasma in a stable state, enabling hydrogen nuclei to merge and release substantial heat. The design employed by CFS is known as a tokamak, which guides plasma into a toroidal or doughnut-shaped configuration.

Conversely, Realta and WHAM are exploring a different approach with a magnetic mirror design. This concept entails positioning two powerful magnets apart to generate a magnetic field that captures plasma in a cylindrical configuration similar to a Tootsie roll. The plasma is compressed at the ends by the magnets, causing hydrogen ions to oscillate and collide within the wider central section, facilitating fusion and the release of energy.

WHAM is currently a pivotal platform for testing the magnetic mirror reactor concept. Knowledge garnered from these trials will guide Realta in constructing its demonstration reactor, dubbed Anvil, expected to be completed in the latter part of the decade. Anvil, which will be an upscaled version of WHAM, aims to further our understanding of this reactor configuration and assess material behavior in a functional reactor environment.

Following the Anvil project, Realta envisions deploying Hammer, a next-generation model featuring dual magnets at each end for extended length and increased power generation capabilities.