The company’s revolutionary technology promises simpler “software-controlled” magnets for stellarators
In The Fusion Report, we have covered a variety of fusion technologies over the past several years, and one of the more interesting ones is the concept of software control magnets for stellarators. This approach utilizes an array of hundreds of simple magnets that can be infinitely and arbitrarily controlled. Yesterday, Thea announced the successful operation of the company’s first full-size, full-current, and full-field stellarator planar shaping coil, paving the way for their full-scale stellarator to be online by 2030.
The Complexity of Stellarator Design
Stellarators have several advantages over tokamaks when it comes to building and designing them. Tokamaks produce a helical field using a combination of external coils and a strong electrical current induced directly within the plasma itself to contain it. In contrast, stellarators generate the required magnetic twist as a function of their geometry. Stellarators generate the entire twisting or helical magnetic containment field via external magnets alone, requiring no large net current in the plasma. This makes stellarators more stable than tokamaks, which have inherent field instabilities.
However, the tradeoff for this stability is the complexity of a stellarator’s magnetic coils. In a stellarator, the coils need to be 3-dimensional non-axisymmetric shapes. Even with 3D computer-aided design (CAD), a stellarator’s coils are still highly complex, often being non-planar and even non-identical, making them hard to “tune” if necessary to correct any instabilities found during testing. This is the problem that Thea’s design was built to address; by using simple “pixel” magnets, they are able to create arbitrary magnetic fields under software control. This allows the Thea stellarator to produce the magnetic fields required for stable operation without expensive 3D magnets. This approach underlies Thea’s approach to EOS, its upcoming stellar fusion system to be online in 2030.
Thea Energy Planar Coil Stellarator
“We founded Thea Energy to unlock a simpler way to build the stellarator, and the team has now proven that by successfully designing, building, and operating multiple magnet hardware systems in a matter of a few years,” said David Gates, Ph.D., co-founder and CTO of Thea Energy. “Eos will derisk the programmatic and executional aspects of ‘Helios’, our first fusion power plant, and now we have verified Eos-spec shaping coil magnets and the manufacturing technologies required to build and scale them. Our magnets are overwhelmingly easier to build compared to the complex ones used in prior generations of the stellarator. We are already starting to think about how to further scale manufacturing and quality assurance processes in our next phase. We look forward to completing additional operational campaigns that show the robustness of these magnets and sharing more on our breakthroughs with the industry.”
What Was Tested at Thea
Yesterday, Thea announced the successful operation of its first full-size, full-current, and full-field stellarator planar shaping coil. At 20 degrees K, the Eos-spec coil generated the full magnetic fields and currents required for the upcoming Eos integrated stellarator. This magnet created and controlled a magnetic field of over 6 T, in line with the company’s specified performance requirements. Future test campaigns will continue the validation of the robustness of the Eos coils, including quench survivability and additional digital twin modeling. This follows the in-house superconducting magnet design and manufacturing at Thea’s headquarters in Kearny, NJ. The company plans to open a second facility in 2026 to further scale the manufacturing of its shaping coils.
Brian Berzin, co-founder and chief executive officer of Thea Energy, said, “Our engineering philosophy centers on hardware that is designed for manufacturability, constructability, maintenance, and long-term commercial operation. These magnets can be built and assembled at scale using basic, cost-effective manufacturing technologies. For fusion to deliver baseload power at scale, the hardware must be streamlined and reproducible. This latest milestone confirms that our core magnet technology meets those exact criteria, paving the way for commercialization.”
Conclusion: A Good Approach; Now Thea Needs to Raise Money
The great thing about Thea’s approach is that it is a truly novel concept and if it works as expected, it provides them with a lot of flexibility to further tune their system over time. In essence, they don’t have to get the physics right before they can build their hardware. Moreover, it avoids expensive iterations on the design and fabrication of Thea’s superconducting magnets, which is neither a cheap nor quick thing.
On the other hand, of all the fusion companies that are out there, Thea is one of the more lightly capitalized ones, with only $30 million in total private funding raised over the past couple years. This is about 1% of what Commonwealth Fusion Systems (CFS) has raised in the past five years (slightly under $3B). Thea will have to have a massive fundraising round fairly soon to the point of building an actual prototype power plant. Like for all fusion companies, we will keep our fingers crossed for them 😊.
