Magnetized Target Fusion Reaches 8.4 Million Degrees

In May 2025, General Fusion's chief executive published an open letter announcing layoffs and asking for money. The company had built a fusion machine it could not afford to run.

Thirteen months later, that machine produced the result it was built for.

What LM26 Achieved

On 22 June 2026, General Fusion reported that Lawson Machine 26 had heated plasma to approximately 8.4 million degrees Celsius — 0.72 keV, with a margin of 0.08. The figure represents more than a threefold temperature increase during mechanical compression.

What distinguishes the result is the method. Magnetized target fusion heats plasma solely by squeezing it after formation, with no external heating applied during compression. General Fusion states this is believed to be a unique outcome for the approach.

The company has posted a technical paper and submitted it for peer review. That review has not been completed.

How Mechanical Compression Works

Most fusion programmes take one of two paths. Tokamaks confine plasma using large superconducting magnets. Inertial confinement, as at the US National Ignition Facility, uses laser arrays.

General Fusion does neither. LM26 forms a magnetised plasma, then mechanically collapses a solid lithium liner around it. Compressing the plasma raises both temperature and density toward the conditions fusion requires.

The appeal is cost. No laser array, no large magnet system. The company describes LM26 as roughly half the diameter of a future commercial plant, which is why it calls the machine commercially relevant rather than purely experimental.

Development was fast. LM26 was assembled in December 2024, produced first plasma in February 2025, and completed its first plasma compression that April.

What Comes Next

The 0.72 keV result falls short of LM26's stated next target of 1 keV, or 10 million degrees. Beyond that sit 10 keV and eventually the Lawson criterion — the combination of temperature, density and confinement time required for net energy in the plasma.

General Fusion says experimental results closely matched its computer models, which it presents as evidence that further upgrades should behave predictably. Collaborators on the work include the UK Atomic Energy Authority, Princeton Plasma Physics Laboratory and General Atomics.

The Financial Story Behind the Physics

Founded in 2002 in Richmond, British Columbia, General Fusion has raised roughly US$400 million, including more than US$100 million from governments. Backers include Jeff Bezos and Shopify co-founder Tobias Lütke.

That history nearly ended in 2025. After the layoffs, the company raised US$88 million privately, then agreed in January 2026 to merge with Spring Valley Acquisition Corp. III.

The merger closed on 13 July 2026, making General Fusion the first pure-play fusion company on public markets, trading as GFUZ. Most SPAC investors redeemed. The Globe and Mail estimated the company received under US$30 million from the trust, though a separate US$108 million private placement was unaffected. General Fusion says it holds about US$150 million, enough to fund operations through the end of 2028.