Record high fusion plasma temperature achieved in US to boost path to commercial fusion

A Washington-based company has achieved a new industry-first fusion energy milestone. Helion becomes the first privately developed fusion energy machine to demonstrate measurable deuterium-tritium (D-T) fusion.

Helion achieved plasma temperatures of 150 million degrees Celsius (MºC). Both milestones mark significant breakthroughs in Helion’s vision to make commercially viable fusion energy a reality and are firsts for the private fusion industry.

Path to commercializing fusion

“We believe the surest path to commercializing fusion is building, learning and iterating as quickly as possible,” said David Kirtley, co-founder and CEO of Helion.

“We’ve built and operated seven prototypes, setting and exceeding more ambitious technical and engineering goals each time. The historic results from our deuterium-tritium testing campaign on Polaris validate our approach to developing high power fusion and the excellence of our engineering.”

Ability to operate and show scaling across multiple fuels

Helion began operating its 7th-generation Polaris prototype at the end of 2024. This January, it became the first and currently only private fusion energy machine to use deuterium-tritium fuel, demonstrating the company’s ability to operate and show scaling across multiple fuels.

Helion was also the first company to receive regulatory approval to possess and use tritium for the purpose of demonstrating fusion energy production. Achieving thermonuclear fusion using deuterium-tritium fuel is one step in Polaris’ testing program. The company will continue testing to reach optimal temperatures for deuterium-helium-3 fusion, a fuel Helion will use for commercial operations, according to a press release.

“After reviewing the latest results from the Polaris prototype operating on D-T, I am proud of how far the field has come since the earliest FRC work at UW and Los Alamos,” said Dr. Alan Hoffman, a leading expert on FRC plasmas with over 40 years’ experience developing fusion devices.

FRC research in the U.S. first began at Los Alamos, was continued at a private company, Math Sciences North West, and, due to encouraging results, proceeded to the construction of the Large S device at the University of Washington under funding from the U.S. Department of Energy, led by Dr. Hoffman.

“I continue to see the technology scaling and Helion’s plasma energy recovery enabling this technology for commercial scale.”

With its latest technical accomplishments, Helion continues to set the pace for the fusion industry, creating a path to produce low-cost, carbon-free power from fusion for commercial use. In July 2025, Helion began building on the site of Orion, its first commercial machine, in Malaga, Wash., which will deliver electricity from fusion to the grid for Microsoft.

With its latest technical accomplishments, Helion claims that it plans to set the pace for the fusion industry, creating a path to produce low-cost, carbon-free power from fusion for commercial use. In July 2025, Helion began building on the site of Orion, its first commercial machine, in Malaga, Wash., which will deliver electricity from fusion to the grid for Microsoft.