Fusion power can potentially provide the world with safe, clean, and renewable power. As recent advances in superconducting magnet fabrication and AI-enabled field optimization propel stellarators from academic endeavors toward commercially deployable fusion systems, this article explains why the resulting surge—and U.S. concentration—of stellarator patent filings marks an important inflection point for IP strategy, freedom-to-operate risk, and competitive positioning in next-generation fusion power. Fusion power technologies are divided into two main categories: (1) tokamaks and (2) stellarators.
Overview of Tokamaks
Tokamaks work by running an electrical current through the plasma itself, thereby creating a magnetic field from the inside-out. In a tokamak, three sets of magnetic field coils confine plasma particles in a torus (donut shape) to generate a plasma and achieve conditions necessary for fusion. Tokamaks utilize a central solenoid to create a poloidal field (short way around torus), toroidal field coils to create a toroidal field (long way around torus), and outer poloidal field coils to shape and position the plasma, which all combine to generate a total helical magnetic field in the torus that confines the path of travel of charged plasma particles.[1]
Figure 1: Tokamak design includes a central solenoid (green), toroidal field coils (blue), and poloidal field coils (grey) to generate a total helical magnetic field (black) to confine the plasma for fusion. [Image courtesy of EUROfusion]
Overview of Stellarators
Stellarators rely solely on external magnets, and no current passes through the plasma. Stellarators utilize complex electromagnetic (e.g., superconducting) coils to confine plasmas in a Möbius-like strip using three-dimensional (3D) magnetic fields arranged in a torus without relying on induced plasma currents to sustain the plasma.[2] Stellarators require less injected power to sustain the plasma, have greater design flexibility, and simplify some aspects of plasma control. However, stellarators are far more complicated to build, and each magnet must be placed with exact precision and calculated to less than 1 mm.
Figure 2: Stellarator design includes planar coils that provide strong toroidal (ring) magnetic fields and non-planar coils that provide both toroidal and poloidal (twist) magnetic fields to generate a total helical magnetic field that continuously twists in a Möbius-like strip to confine the plasma (pink) for fusion without relying on plasma current. [Image courtesy of New Energy and Fuel[3]]
Stellarator designs are generally based on globally optimizing a 3D toroidal magnetic field that produces nested flux surfaces, often with discrete toroidal symmetry, after which non-planar coils are numerically optimized to provide toroidal and poloidal magnetic fields that reproduce the desired magnetic configuration.[4] Stellarators have been proposed since the 1950s, but renewed interest in stellarators has developed due to advances in magnetic material production and modeling of magnetic and plasma confinement with the use of artificial intelligence (AI).
Companies Working on Stellarators
In the U.S., several companies are developing and manufacturing operational stellarators for power grid integration. Type One Energy has partnered with the Tennessee Valley Authority (TVA) to build a stellarator fusion power facility outside Nashville, TN and expects integration with the TVA power grid by 2030.[5],[6] In Germany, the Wendelstein 7-X stellarator has shown extended stable fusion reactions for over 8 minutes at a temperature of 18 million °C and currently holds the record for the triple product (density × temperature × confinement time) that measures fusion performance, which further confirms stellarator viability in the future.[7] The stellarator systems have demonstrated longer controlled fusion reactions than the comparable tokamak system at the International Thermonuclear Experimental Reactor (ITER).
Impact on IP
Since 2022, stellarator patent filings have increased significantly. Also, the geographic concentration of stellarator patent filings in the U.S. has direct implications for IP strategy. After a long period of relatively modest and steady filing activity through the mid‑2010s, global stellarator patent filings increased sharply from 10 patent families in 2022 to 56 patent families in 2025. The U.S. emerges as the single largest jurisdiction by family count (over 45%), materially outpacing Europe, Germany, and China, underscoring the U.S. as the epicenter for proprietary stellarator technology.
Figure 3: Global patent family publications directed to stellarators since 2000, showing a rapid increase in filings since 2022.
This trend is reinforced by the identity of top filers: a mix of U.S.-based private fusion companies (e.g., Type One Energy, Tokamak Energy, and Fuse Energy Technologies), major research universities (e.g., Princeton, MIT, and University of Texas), and the U.S. Department of Energy. This mix indicates both commercial competition and sustained public-sector innovation. Compared to earlier periods dominated by academic and international research institutions, the recent surge of corporate filers likely reflects increasing privatization and commercialization of stellarator concepts, with denser claim coverage and overlapping ownership in the U.S. (e.g., U.S. Patent No. 12,009,111 titled “Planar Coil Stellarator” is owned by Princeton but under confirmatory license to U.S. Department of Energy). This suggests a tightening freedom‑to‑operate landscape in the U.S., heightened importance of early U.S. filings and continuations, and a growing need for proactive monitoring of competitor portfolios and university spin‑out activity as stellarators move from experimental devices toward deployable fusion power systems.
Conclusion
The renewed momentum behind stellarators reflects a convergence of technical feasibility and commercial intent that was largely absent during earlier generations of fusion research. As described above, advances in superconducting magnet fabrication, precision manufacturing, and AI‑enabled plasma and field modeling have materially reduced historical barriers associated with stellarator complexity, while preserving their intrinsic advantages—steady‑state operation without plasma current, reduced disruption risk, and greater operational flexibility compared to tokamaks. Together, these developments reposition stellarators as a credible and increasingly attractive pathway toward grid‑relevant fusion power, rather than a purely academic alternative.
From an IP perspective, the data point to a clear inflection. After decades of relatively modest activity, stellarator patent filings accelerated sharply since 2022, with filings focused mainly in the U.S. This shift coincides with the entry of well‑capitalized private fusion companies, increased federal involvement, and university research programs that are now more closely aligned with commercialization objectives. The resulting patent landscape is denser, more competitive, and more U.S.‑centric than in prior periods dominated by international research consortia. For in‑house teams, the takeaway is to file early and broadly in the U.S., build layered claim sets directed to core aspects of coil geometry, magnetic field optimization, and control methodologies, and actively monitor competitor and university portfolios to preserve optionality and mitigate freedom-to-operate risk as stellarator programs move toward deployment.
[1] U.S. Department of Energy, “DOE Explains…Tokamaks” [https://www.energy.gov/science/doe-explainstokamaks]
[2] U.S. Department of Energy, “DOE Explains…Stellarators” [https://www.energy.gov/science/doe-explainsstellarators]
[3] New Energy and Fuel, “Fusion Stellarator Device Efficiency Improvement Confirmed,” August 19, 2021 [https://newenergyandfuel.com/2021/08/19/fusion-stellarator-device-efficiency-improvement-confirmed/]
[4] S. R. Hudson, “Stellarator Coil Design: Past, Present and Future,” Princeton, Simons “Hidden Symmetries” Summer School, 2019 [https://hiddensymmetries.princeton.edu/sites/g/files/toruqf1546/files/simonssummerschoolhudson190820.pdf]
[5] Type One Energy, “TVA and Type One Energy Sign First Contracts for Fusion Power Plant Project,” July 22, 2025 [https://typeoneenergy.com/tva-type-one-sign-first-contracts/]
[6] Type One Energy, “Type One Energy Submits Initial Licensing Application for Tennessee’s First Commercial Fusion Project at Bull Run Site,” January 29, 2026 [https://typeoneenergy.com/tva-and-type-one-energy-submit-first-license-application-for-fusion-in-tn/]
[7] Frank Fleschner, “Wendelstein 7-X sets new performance records in fusion research,” Max Planck Institute for Plasma Physics, June 3, 2025 [https://www.ipp.mpg.de/5532945/w7x]
