World-first magnets set for fusion power plant testing

Fusion energy requires strong magnetic fields to confine and control extremely hot, positively-charged hydrogen fuel, which becomes a plasma several times hotter than the Sun.

Tokamak Energy’s new Demo4 facility – with a magnetic field strength of over 18 Tesla - will consist of 44 individual magnetic coils manufactured using 38km of HTS tape, which requires five times less cooling power than traditional superconducting materials.

Assembly at Tokamak Energy’s headquarters in Milton Park, near Oxford, will complete this year and testing will extend into 2024, informing designs and operational scenarios for its advanced prototype, ST80-HTS, and subsequent fusion power plant, ST-E1.

Dr Rod Bateman, HTS magnet development manager at Tokamak Energy, explained that the magnets enable the construction and operations of spherical tokamaks, with Demo4 facilitating the creation of substantial magnetic forces for test in relevant scenarios.

“The breakthrough to enable a compact spherical tokamak was the development of high temperature superconducting material which can operate in high magnetic fields,” he said. “Our co-founders, Dr David Kingham and Professor Mikhail Gryaznevich, were among the first pioneers to identify the opportunity to apply this technology to fusion energy – replacing copper magnets.”