Pioneering commercial
fusion technology
Pioneering commercial
fusion technology
The spherical tokamak
Tokamaks are the most researched and best understood path to fusion energy.
A tokamak is a device that uses a magnetic field to confine and control a plasma. Scientists first realised the potential of tokamaks to achieve fusion conditions back in the 1960s. Then in the 1980s, a study by one of our founders, Alan Sykes, revealed that modifying the shape of the tokamak would significantly improve performance.
The compact spherical tokamak, which has a more compressed, spherical shape, was found to offer key advantages in terms of efficiency, plasma stability, and cost-effectiveness. It is now the basis for fusion energy programmes around the world, including the UK government’s Spherical Tokamak for Energy Production (STEP) project.
Tokamak Energy is the only private company with over a decade’s experience developing and operating tokamaks.
ST40
Our ST40 high-field compact spherical tokamak is the most advanced of its kind in the world.
In 2022, we reached a world-first plasma ion temperature of 100 million degrees Celsius, over six times hotter than the centre of the sun, and considered the threshold for fusion energy. A peer-reviewed scientific paper on the achievement was published by the Institute of Physics in 2023.
We also demonstrated the highest ‘triple product’ of any private fusion company; a metric of plasma temperature, density and confinement time which is a key measure of progress on the path to realising commercial fusion conditions. These achievements support the spherical tokamak as the optimal route to clean, affordable and globally deployable fusion power.
HTS magnets for fusion
Tokamaks use strong magnetic fields to control the shape and position of the plasma, trapping it long enough for fusion to occur.
High temperature superconducting (HTS) magnets generate these fields at higher temperatures than conventional superconductors, making them more than five times as energy-efficient. Combining the increased efficiency of the spherical tokamak with the improved magnetic confinement made possible by high-field HTS magnets offers the most viable and cost-effective route to fusion energy.
Tokamak Energy is a world leader in HTS technology. Our fusion magnet coils are wound from HTS tapes, which are multi-layered conductors typically 12mm wide and less than 0.1 mm thick made mostly of strong and conductive metals, but with a crucial thin internal coating of ‘rare earth barium copper oxide’ (REBCO) superconducting material. Our advanced winding, testing and production techniques are the key to creating robust and reliable HTS magnets.
HTS is a transformative technology for getting clean, limitless fusion energy on the grid faster.
Demo 4
Our Demo4 magnet system, currently under construction in a purpose-built test facility, is the next key step on our pathway to fusion energy.
Demo4 is designed as a complete balanced set of HTS magnets in a tokamak configuration, which will allow us to test them in fusion power plant-relevant scenarios for the first time.
It comprises of 44 individual HTS coils assembled into 14 toroidal field limbs and two poloidal field coils, forming a cage-shaped structure. The system will operate in a vacuum at 20 Kelvin (-250°C) and will have a magnetic field strength of nearly a million times stronger than the Earth’s magnetic field.