Why the 1 keV threshold matters
Canadian technology firm General Fusion superheated plasma above 12 million degrees Celsius inside its experimental prototype, the Lawson Machine 26 (LM26). The device reached an electron temperature of 1.1 kiloelectronvolts (keV) just before peak compression. In fusion physics, passing 1 keV is an internationally recognized milestone, and only a handful of experimental reactors worldwide have ever reached it.
A different route: mechanical compression
Until now, every lab that crossed this mark used massive superconducting magnets or high-powered lasers. General Fusion instead relies on a mechanical method called Magnetized Target Fusion (MTF): magnetically confined plasma is injected into a chamber and crushed over several milliseconds by a contracting solid metal wall. According to the company, LM26 is the first machine to reach this temperature through low-speed physical compression.
How the measurement was made
Proving the temperature required a joint effort with the UK Atomic Energy Authority (UKAEA). The team used Thomson scattering, shining a laser through the plasma and measuring how light scatters off high-energy particles; the hardware relied on a custom polychromator built at Culham. The test data is now published on the company's portal and submitted to an academic journal for peer review.
What comes next
Technicians are already refitting LM26 and boosting its compression systems toward a 10 keV target, roughly 100 million degrees Celsius. That milestone leads toward the Lawson criterion, the balance of heat, density and confinement time needed for net electricity. If these engineering milestones hold, General Fusion expects to build its first operational grid pilot plant around 2035.
