Europe · UK
Saturday, June 13, 2026
Crossfield Fusion
Compact closed-orbit velocity-resonant system
Magneto-Inertial
Advanced fuels
Undisclosed
TBD
Investor brief
Non-thermal fusion in a closed-orbit velocity-resonant trap
Executive Summary
Crossfield Fusion is an early-stage UK company exploring closed-orbit velocity-resonant confinement — a non-thermal scheme that holds ions in a narrow energy band where the fusion cross-section is highest, rather than relying on Maxwellian plasma heating.
Strategic Thesis
Forget Maxwellian plasmas: hold the ions exactly at the cross-section peak and the reactor becomes orders-of-magnitude smaller.
Technical & Economic Profile
Architecture class
Magneto-Inertial, Pulsed & Alternative Cores
Pulsed compression schemes that explicitly avoid massive static superconducting magnets, prioritising upfront-capex reductions and modular replicability.
Reactor design
Magneto-Inertial — velocity-resonant
Core tech focus
Non-thermal ion distribution control
Key milestones
Pre-commercial.
How Crossfield Fusion sits vs peers
Non-thermal velocity-resonant approach: holds ions strictly in a narrow velocity band where the fusion cross-section peaks, bypassing the Maxwellian-distribution bremsstrahlung problem that constrains aneutronic thermal plasmas.
Class engineering bottlenecks
- Pulsed-rep-rate engineering: sustaining 1–10 Hz operation with millisecond-scale energy recovery.
- For aneutronic FRC (TAE), bremsstrahlung scales as Pbrems ∝ Tₑ^½, capping Pfus/Pbrems at ~0.2–0.3 without non-thermal ion distributions.
- For MTF (General Fusion), liquid-metal vortex stability under pneumatic shock and synchronisation of dozens of pistons.
- For sheared-flow Z-pinch (Zap), maintaining kink-stability at commercial pulse repetition rates.
LCOE drivers
- Elimination of large superconducting magnet assemblies removes the single largest capex line in tokamaks.
- Direct-conversion architectures bypass the 35–40% Rankine/Brayton thermodynamic ceiling, pushing net plant efficiency past 60–70%.
- Liquid-metal first-walls (General Fusion) eliminate first-wall replacement cycles entirely.
Sourced from the 2026 Global Fusion Energy Comparison — triple-product thresholds, direct-energy-conversion architecture, materials limits, and the LCOE / Qecon framework.
Founding Team
Founded by James McKenzie, Crossfield Fusion is focused on achieving immediate, localized impacts using compact nuclear technology. McKenzie structured the company around an optimized, highly efficient variation of Inertial Electrostatic Confinement (IEC). By deliberately aiming away from massive, long-term grid plants, McKenzie's design targets immediate commercial markets—specifically, creating portable, low-cost fusion devices optimized for decentralized medical isotope production and advanced neutron radiography.
James McKenzie
Advanced engineering developer and industrial technology pioneer
The Problem
Global electricity demand is entering an unprecedented growth phase driven by AI infrastructure, data centers, transport electrification, industrial decarbonization, water desalination, and advanced manufacturing. Solar suffers intermittency, wind capacity-factor variability, natural gas carbon emissions, conventional nuclear cost and deployment speed, and batteries energy-density and duration limits. The world requires a new source of clean, dispatchable baseload energy. Fusion represents the ultimate energy source — the challenge is making it commercially practical.
Closed-Orbit Velocity-Resonant Confinement
Conventional fusion plasmas waste energy heating ions over a broad Maxwellian distribution. Crossfield's approach holds ions precisely at the energy where they are most likely to fuse — an order-of-magnitude reactivity gain at the same particle inventory.
Velocity-Resonant Trap
Closed-orbit confinement engineered to maintain a narrow ion-energy distribution.
Non-Thermal Operation
Avoids the thermalisation losses that limit tokamak and FRC efficiency.
Fuel Strategy
Advanced Fuels
Non-thermal operation naturally favours advanced fuels with peaked cross-sections.
Product Platform
Concept R&D
Stealth-phase concept and theoretical validation.
Energy Conversion
Thermal (Rankine/Brayton)
Neutronic (D-T)
33–40% electrical
Deuterium-tritium fusion releases ~80% of its energy as 14.1 MeV neutrons, which deposit their kinetic energy in a surrounding blanket. The heat drives a conventional steam (Rankine) or supercritical-CO₂ (Brayton) turbine.
Conversion chain
- 1D-T plasma
- 214.1 MeV neutrons (80%) + 3.5 MeV alpha (20%)
- 3Neutrons → lithium-bearing blanket (heat + tritium breeding)
- 4Heat → steam/CO₂ turbine → electricity
The most thoroughly understood fusion fuel cycle, highest cross-section at achievable temperatures, and proven back-end engineering (steam turbines are 19th-century technology). Trade-offs: neutron-induced materials damage, tritium handling, ~33–40% Carnot-limited efficiency.
Economic Vision
If ion-velocity-space stability against thermalisation can be solved, the reactor scale needed for breakeven drops by orders of magnitude.
Vision
Make fusion a velocity-space engineering problem.
Mission
Prove non-thermal closed-orbit fusion is real.
Engineering Bottlenecks
- Velocity-space stability against thermalisation
The description above reflects Crossfield Fusion's publicly stated technology goals, roadmap and architecture. Many elements — particularly net-energy gain at scale, advanced fuel cycles, and grid-relevant economics — remain ambitious objectives that have not yet been demonstrated commercially anywhere in the fusion industry. Forward-looking statements should be treated as engineering targets, not certainties.
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Citations & Sources
Academic & financial rigor- [01]
The Global Fusion Industry in 2025
Fusion Industry Association · Jul 2025
- [02]
Company disclosures and press releases
Crossfield Fusion
- [03]
Peer-reviewed plasma physics literature
Journal of Plasma Physics / Nuclear Fusion