Helical Fusion Publishes Peer-Reviewed Paper on HTS Magnet Technology Validated Through Collaboration with NIFS
- 2 days ago
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Updated: 17 hours ago
Results first announced in 2025 have now been formally published in a peer-reviewed international journal, marking another engineering milestone toward commercially viable fusion power.
Key Points
Validation results for Helical Fusion's proprietary high-temperature superconducting (HTS) conductor UROCOIC, first announced in 2025, have now been published in the peer-reviewed Journal of Physics: Conference Series (IOP Publishing).
The paper demonstrates stable HTS magnet performance under high-field and high-current conditions representing selected aspects of future fusion reactor magnetic environments.
The work combines Helical Fusion's conductor technology, advanced manufacturing by Japanese industrial partners, and experimental validation through joint research with the National Institute for Fusion Science (NIFS).
The publication represents another important engineering milestone in the Helix Program, supporting the development of commercially viable fusion power.
Helical Fusion Co., Ltd. announces the publication of a peer-reviewed paper describing a key milestone in its high-temperature superconducting (HTS) magnet development program.
The paper, published in the Journal of Physics: Conference Series (IOP Publishing), follows its presentation at the 38th International Symposium on Superconductivity (ISS 2025) and formalizes results that were first announced in 2025. Following peer review, the work has become part of the scientific literature, making the findings accessible to the global fusion research community.
The published paper reports validation results for UROCOIC, Helical Fusion's proprietary HTS conductor developed for Helical Stellarator magnets. The test coil was manufactured by a specialized Japanese manufacturing partner and experimentally evaluated through joint research with the National Institute for Fusion Science (NIFS).
This publication marks the next chapter of a milestone first shared in 2025, reinforcing Helical Fusion’s commitment to advancing fusion technology through rigorous engineering and scientific collaboration.
The HTS conductor evaluated in this study is being developed for implementation in both Helix HARUKA, Helical Fusion’s Integrated Demonstration Device, and Helix KANATA, the company’s first commercially viable fusion power plant under the Helix Program.
Background
High-temperature superconducting magnets are one of the key enabling technologies for commercially viable fusion power plants. Helical Stellarators require superconducting coils with complex three-dimensional geometries while maintaining high current capacity and mechanical robustness under intense electromagnetic loads.
To address this challenge, Helical Fusion developed UROCOIC (Unitized Reinforcing Outer Cover On Internal Components), a proprietary HTS conductor architecture designed specifically for Helical Stellarator applications.
Technical Results
The published paper reports the validation of a double-pancake (DP) coil wound with Helical Fusion's proprietary UROCOIC conductor under cryogenic conditions.
Key achievements include stable operation at 40 kA without quench under a 7 T external magnetic field, local magnetic fields up to 8.9 T while withstanding electromagnetic forces of 356 kN/m, and robust no-insulation coil performance during abrupt magnetic-field changes.
These results represent a significant engineering step toward reactor-scale HTS magnets for commercially viable fusion power.
(Reference) A peer-reviewed paper on an earlier stage of the development (U-shaped WISE conductor demonstration) was published in Plasma and Fusion Research.
[Figure 1: Helical Fusion’s proprietary UROCOIC conductor, the double-pancake test coil, and an illustration of the Helical Stellarator concept]
Summary of the published research
Using an HTS coil fabricated with Helical Fusion’s proprietary large scale HTS conductor for reactor application (*1) (a “double-pancake coil”), the research team conducted cryogenic current-carrying tests under conditions replicating the magnetic environment inside a fusion device (*2).
Test environment
Temperature: 10–30 K (−263°C to −243°C); initial temperature: 10 K
Magnetic field: 7 T (applied by external coils); maximum field experienced by the coil: 8.9 T
Key results
Achieved stable 40 kA operation under a 7 T external magnetic field
Obtained time-constant data and other measurements for characterization as a no-insulation coil
Helical Fusion’s Business Perspective
Based on these results, Helical Fusion concludes that its proprietary UROCOIC conductor satisfies the necessary conditions to advance toward demonstration in the Integrated Demonstration Device “Helix HARUKA.”
[Figure 2: Double-pancake coil used in the test]
[Figure 3: Stable 40 kA operation under a 7 T external magnetic fieldTime evolutions of operational parameters demonstrating stable operation at the condition of 10-30 K / 7 T with a transport current of 40 kA for 280 s. The table summarizes the corresponding steady‑state values. (based on Y. Narushima et al., ISS2025 AP3-03; processed by Helical Fusion)]
[Figure 4: Analytical figures/tables for evaluating no-insulation coil characteristics]
Reference video: (YouTube link)
Industrial Collaboration and the Helix Program
This achievement reflects Helical Fusion's approach of combining proprietary fusion technologies with Japan's advanced manufacturing ecosystem. The project brought together Helical Fusion's conductor technology, manufacturing by a specialized Japanese industrial partner, and experimentally evaluated through joint research with the National Institute for Fusion Science (NIFS).
The publication represents another engineering milestone for the Helix Program, Helical Fusion's roadmap toward commercially viable fusion power in the 2030s. The company aims to integrate these technologies into the Integrated Demonstration Device, Helix HARUKA, before progressing toward Helix KANATA, its first commercially viable fusion power plant.
Public–Private Partnership
The development of the UROCOIC conductor is being carried out under Japan’s MEXT SBIR Phase 3 program, one of the country’s flagship initiatives supporting deep-tech commercialization.
Together with the ongoing collaboration with the National Institute for Fusion Science (NIFS) and Japanese manufacturing partners, this achievement highlights how disciplined execution, scientific research, industrial manufacturing, and public investment can work together to accelerate commercially viable fusion power.
Why This Publication Matters
While the experimental results were first announced in 2025, publication in a peer-reviewed journal represents an important milestone in their technical maturity. Following peer review, the work is now formally incorporated into the scientific literature, making the findings accessible to researchers and engineers worldwide while contributing engineering knowledge for future HTS magnet development.
Comment from Junichi Miyazawa, Co-Founder & Vice CTO
"Developing high-temperature superconducting magnets is fundamentally an engineering challenge requiring advances in conductor technology, manufacturing, mechanical design, and system integration.This publication reflects years of collaboration between Helical Fusion, the National Institute for Fusion Science, and our manufacturing partners. It demonstrates how expertise from academia and industry can be brought together to solve the engineering challenges required for commercially viable fusion power.While this paper marks an important milestone, it is not our destination. We will continue advancing the Helix Program and integrating these technologies into Helix HARUKA, bringing us another step closer to realizing the world's first commercially viable fusion power plant based on the Helical Stellarator.I would like to express my sincere appreciation to everyone who contributed to this achievement."
Paper Information
Title: Experiment of a Double-Pancake Coil Wound by UROCOIC Conductor for Application in Helical Fusion Reactors
Journal: Journal of Physics: Conference Series (IOP Publishing), peer-reviewed conference proceedings
First Author: Yoshiro Narushima, Assistant Professor, HF Joint Research Group, National Institute for Fusion Science / The Graduate University for Advanced Studies, SOKENDAI
Related Release: https://global.helicalfusion.com/post/helical-fusion-achieves-milestone-toward-commercial-fusion-energy-advancing-to-integrated-demonstra
About Helical Fusion
Helical Fusion Co., Ltd. is developing the world’s first commercially viable fusion power plant based on the Helical Stellarator—a reactor concept capable of continuous, disruption-free operation. Through the Helix Program, the company is advancing plant-scale technologies including HTS magnets, blanket systems, and integrated engineering demonstrations, targeting commercial operation in the 2030s.
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*1 This coil is made using advanced high-temperature superconducting (HTS) technology, and it was constructed without electrical insulation. This is the world’s first example of testing a coil sample—wound with a large-scale conductor employing no-insulation technology—inside an externally applied magnetic field.
*2 “the magnetic environment inside a fusion device” refers to a setting in which external magnetic fields—separate from those generated by the coil itself—are present, creating complex electromagnetic interactions between multiple currents through the magnetic field. In future fusion power plants, such environments are expected to include intense radiation, neutron flux, and even stronger magnetic fields.
