General Fusion partners with General Atomics on LM26 plasma diagnostics

As General Fusion and General Atomics turn their attention to measuring plasma at 100 million degrees Celsius, the diagnostics race traces back to a machine that took under two years to build from the ground up

(Image courtesy of General Fusion)

General Fusion and General Atomics have announced a collaboration to develop advanced diagnostic systems for the LM26 fusion demonstration program, targeting the precise plasma measurement capabilities the Vancouver-based company will need as it pushes toward a 10 keV plasma heating milestone. The partnership directly addresses one of the hardest instrumentation challenges in fusion development: accurately measuring plasma temperatures at 100 million degrees Celsius, where precise data drives every subsequent design and scaling decision.

Advanced plasma diagnostics for the 10 keV milestone

General Atomics is advising on the full diagnostic system architecture required for LM26’s second-phase 10 keV target. That work includes tools to measure ion and electron temperature and density at the conditions General Fusion expects to reach. Simultaneously, General Atomics is reviewing data from active LM26 plasma compressions as General Fusion works toward its first milestone, a 1 keV plasma temperature equivalent to 10 million degrees Celsius.

The LM26 machine uses a lithium liner to mechanically compress plasma and is built at 50% commercial-scale diameter. General Fusion designed, built, and began operating the machine in under two years, announcing first operations in early 2025. The milestone sequence the company is targeting – 1 keV, then 10 keV, and ultimately the Lawson criterion – represents the combination of plasma confinement parameters required to produce net fusion energy.

General Atomics brings DIII-D expertise to the partnership

General Atomics operates the DIII-D National Fusion Facility, the largest magnetic fusion research device in the United States, under the US Department of Energy. General Fusion previously worked with DIII-D scientists under the DOE Frontiers of Science program, giving the two organisations an established technical relationship on which this collaboration builds.

Wayne Solomon, Vice President of Magnetic Fusion Energy at General Atomics, framed the work as connecting high-quality plasma measurements to design validation – the kind of cross-institutional partnership he described as necessary to accelerate the path toward practical fusion energy.

MTF approach targets industrial scaling without superconductors

General Fusion’s Magnetized Target Fusion approach deliberately avoids superconducting magnets and high-powered lasers, a design choice the company says enables the use of existing materials for durable machines producing cost-effective energy. That practical orientation is central to the company’s argument for reactor economics and industrial scaling, and it is what makes accurate plasma measurement at each milestone so consequential. Without validated diagnostic data, progression along the milestone path cannot be independently confirmed.

General Fusion CEO Greg Twinney described General Atomics as a distinguished technology leader with deep expertise across defense, aerospace, electromagnetic technologies, and fusion research. The company plans to go public through a proposed business combination with Spring Valley Acquisition Corp. III (NASDAQ: SVAC), announced in January 2026.

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