Helion Energy's seventh-generation field-reversed configuration device — designed to be the first private fusion machine to demonstrate net electricity production.
Polaris is Helion Energy's seventh-generation fusion prototype, currently under construction in Everett, Washington. It represents the culmination of a rapid iterative development program spanning six previous devices, each building on the lessons of its predecessor. Polaris is designed to demonstrate net electricity from fusion — a milestone no fusion device, public or private, has yet achieved.[1]
Polaris uses the field-reversed configuration (FRC), a compact toroidal plasma confinement scheme in which the magnetic field is generated primarily by plasma currents rather than external coils. Helion's approach is distinctive in several ways: it uses pulsed, magnetically accelerated FRC plasmas that are collided at high velocity, compressed to fusion conditions, and then allowed to expand against the confining magnetic field to generate electricity directly through electromagnetic induction — bypassing the need for a thermal steam cycle.[2]
The fuel cycle targeted for Polaris and its commercial successor is deuterium-helium-3 (D-3He) fusion, which produces primarily charged particles rather than neutrons. This offers significant advantages for direct energy conversion and reduced neutron-induced activation of reactor materials. However, D-3He fusion requires substantially higher plasma temperatures than the more common deuterium-tritium reaction.[2]
Helion's iterative approach has produced six preceding machines, each demonstrating progressively higher performance. The sixth-generation device, Trenta, achieved plasma temperatures exceeding 100 million degrees Celsius (9 keV) and demonstrated the merging-compression FRC approach at scale. Polaris is designed to reach the higher temperatures and confinement conditions needed for net electricity.[1]
Helion has raised over $600 million in funding, including a $500 million Series E round led by Sam Altman in 2021, with an additional $1.7 billion contingent on milestones. The company's commercial model is to sell electricity directly rather than selling reactors, positioning it uniquely among private fusion companies.[3]