Proxima Fusion is developing quasi-isodynamic (QI) stellarators, a magnetic confinement approach in which toroidal currents cancel out to zero, resulting in uniquely robust features.

W7-X is an invaluable prototype and testbed for this concept.

The scientific basis for QI stellarators has been spearheaded by our partners at the Max Planck Institute for Plasma Physics (for example, Helander & Nührenberg, PPCF 2009 and Goodman, Xanthopoulos, Plunk et al., PRX Energy 2024).

We believe that QI stellarators using high-temperature superconducting (HTS) magnets offer the clearest path to putting fusion on the grid.

In the absence of toroidal plasma currents, current-driven instabilities can be completely eliminated, together with the risk of disruptions that can occur in tokamaks and other stellarator concepts.

QI-HTS stellarators like Proxima's first-of-a-kind fusion power plant concept, Stellaris, also offer a proven heat exhaust concept: the island divertor, which was demonstrated on W7-AS and W7-X at the Max Planck Institute for Plasma Physics.

Superconducting materials have zero electrical resistance, and have been revolutionizing magnet technology for decades.

But conventional superconductors require extremely low temperatures, near absolute zero.

Modern high-temperature superconductors (HTS) can reach higher temperatures and magnetic field strengths while also having significantly wider design space, leading to less strict requirements for fusion devices.

HTS technology is at the forefront of leading tokamak developments—but it's equally attractive for stellarators, which are less constrained by current-driven operational limits.

Our peer-reviewed fusion power plant concept, Stellaris, has been published in Fusion Engineering and Design.

Stellaris is the first stellarator concept to integrate electromagnetic, structural, thermal, and neutronics simulations, resulting in a fully coherent design.

Stellaris is designed to produce more power per unit volume than any stellarator power plant designed before.
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The much stronger magnetic fields enabled by HTS magnet technology also allow for a significant reduction in size compared to previous stellarator concepts.
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Stellarators and tokamaks differ in their tradeoffs of design vs. operational complexity: stellarators, while harder to design, are easier to operate, because they can be designed to run stably in continuous operation.

Stellarators have far more degrees of freedom, meaning that they can be optimized in countless ways, while tokamak designs are relatively inflexible.

Tokamaks have so far been at the forefront of fusion science. However, stellarators are now feasible to design and build—and with the publication of Stellaris, QI-HTS stellarators have emerged as the most attractive approach to commercial fusion power plants.