Helion Fusion Prototype Reaches 150 Million Degrees Celsius

Helion Energy, a fusion company based in Everett, Washington, has reached a new high in its work on clean power. Its Polaris prototype machine produced plasma at 150 million degrees Celsius and showed measurable deuterium-tritium fusion. These steps come as the company pushes to build a power plant that will sell electricity to Microsoft starting in 2028.

Background

Helion started in 2013 with the goal of building machines that copy how the sun makes energy, but on Earth and in a controlled way. Fusion joins light atoms to release a lot of heat and could provide power without the waste or risks of today's nuclear plants. The company has built seven prototypes so far, each one bigger and better than the last.

The one before Polaris, called Trenta, hit 100 million degrees Celsius in 2023. That was a record for private fusion efforts at the time. Polaris is the seventh machine and works differently from many others. It uses a method called field-reversed configuration. Plasma rings form at each end of a chamber shaped like an hourglass. Magnets speed them up and smash them together. Then stronger magnets squeeze the hot ball of plasma to make it even hotter. All this happens in under a millisecond.

Helion picks fuels like deuterium and tritium now for tests, but plans to switch to deuterium and helium-3 for its power plants. That mix makes less radiation and fits their design. The company raised money from investors, including Sam Altman, who chairs the board. They also signed a deal with Microsoft to supply power from their first plant, Orion, by 2028.

Orion is under construction in Malaga, Washington, about 130 miles from Seattle. It will produce 50 megawatts, enough for tens of thousands of homes. Microsoft wants the power for its data centers, which use a lot of electricity.

Key Details

Polaris reached 150 million degrees Celsius, which beats the sun's core temperature by 10 times. The sun's center is about 15 million degrees. Experts say 100 million degrees is the starting point for machines that could make useful power. Helion broke its own record from Trenta and now aims for 200 million degrees with Polaris. That higher heat fits their plan to run on deuterium-helium-3 fuel.

The machine also ran on deuterium-tritium fuel and produced signs of fusion from that mix. Deuterium and tritium are forms of hydrogen. When they fuse, they give off neutrons and energy. Helion saw the power output rise as expected, in the form of heat. This makes Helion the first private company to show measurable D-T fusion in its setup.

"With Polaris, we’ve crossed two critical thresholds. We operated with deuterium-tritium fuel and reached plasma temperatures over 150 million degrees Celsius. These are important steps on the road to Orion," said David Kirtley, Helion’s co-founder and CEO.

How Polaris Works

The process starts with gas turned into plasma at the ends of the chamber. Magnets push the plasmas together at high speed. When they meet, the temperature jumps to 10 or 20 million degrees. Then pulsed magnets compress it further to 150 million degrees. The fusion changes the plasma's magnetic field, which interacts with the machine's coils to make electricity directly. No steam turbines needed, unlike some other designs.

Other companies use tokamaks, big doughnut shapes held by strong magnets. Those need over 100 million degrees but take longer to run. Helion's way is smaller and pulses fast, which could make it cheaper to build and run.

"It is exciting to see evidence of D-T fusion and temperatures exceeding 13 keV or 150 million degrees Celsius, and I look forward to seeing more progress," said Ryan McBride, an expert in plasma physics with experience at Sandia National Laboratories and the University of Michigan.

Helion plans more tests on Polaris to hit higher temperatures and prove it works with their main fuel. They ended Trenta operations in 2023 and moved to this new machine.

What This Means

These results put Helion ahead in the race among private fusion firms. Most others aim for the grid in the early 2030s. Helion sticks to 2028, with Orion already building. The Microsoft deal holds them to that date, though they say the power will come from Orion, not Polaris.

Success here could change how we get electricity. Fusion promises steady power without carbon emissions or long-lived waste. It uses fuels from seawater, so plenty available. If Helion delivers, it might speed up other companies and draw more investment.

Experts from the Department of Energy watch closely. Their office funds fusion research and sees Helion's fast tests as a sign of U.S. strength in the field.

"I am impressed with our nation's ingenuity and the pace at which we are de-risking our path to fusion commercialization," said Jean Paul Allain, Associate Director for Fusion Energy Sciences in the Department of Energy's Office of Science. "Seeing the data from the Polaris test campaign, including record-setting temperatures and gains from the fuel mix in their system, indicates strong progress."

Helion must still show it can turn fusion heat into steady grid power. Orion needs more design work before full assembly. Tests will continue to check reliability and output. The company says each step reduces risks for the big plant. If Polaris keeps improving, Orion could follow soon. Fusion stays hard, with many firms chasing the same goal. Helion's path looks solid so far, with real data backing their timeline.