Tokamak Energy Shares Images from Inside the Tokamak Reactor as It Heats Up to 100 Million Degrees Celsius and Produces Plasma.
Image: Tokamak Energy
Tokamak Energy, a commercial fusion energy company based in the UK, utilizes a machine known as the spherical tokamak. This device, shaped like a doughnut, employs powerful magnets to contain a superheated plasma. Plasma is often referred to as the fourth state of matter, following solid, liquid, and gas, and primarily consists of negatively charged electrons and positively charged ions that are separated by the extreme temperatures of their environment.
When hydrogen atoms are heated to the point of becoming plasma, they acquire a positive charge and repel each other. In the Sun, the immense gravitational force creates super-high pressures that can overcome this repulsion. However, such high pressure is nearly impossible to replicate on Earth. Therefore, researchers must heat the plasma to even higher temperatures. The higher the temperature, the faster the atoms move, overcoming repulsion and beginning to fuse, according to Chris Kelsall, CEO of Tokamak Energy.
This process requires temperatures exceeding 100 million degrees Celsius, which is more than six times the temperature at the core of the Sun. “When fused, hydrogen atoms create helium atoms and a neutron carrying 80% of the energy from the reaction. That’s what we collect,” Kelsall stated. The footage shared by Tokamak Energy captures the moment the reactor reaches the milestone of 100 million degrees Celsius. The entire process occurs in just a fraction of a millisecond, with only a very small amount of atoms fusing. To achieve full scale, fusion power plants need to operate for hours at a time, and no such plant currently exists.
To maintain these extreme conditions, the superheated plasma must be confined to a small area, which is why the tokamak relies on magnets. “Essentially, you need a very large magnet system,” said Tony Langtry, head of engineering at Tokamak Energy. “The magnetic field needed to control the plasma is created by a massive current flowing through conductors. As the current passes through the conductors, they produce a magnetic field. Since the plasma also carries a current, it reacts to and is controlled by the magnetic field.”
Inside the Tokamak Energy fusion reactor.
The current operational tokamak model at the facility is the ST40, which uses copper magnets to contain the plasma. According to Kelsall, copper is a very good conductor. However, conventional materials like copper have resistance, which opposes the current and converts some of its energy into heat, leading to energy loss. In contrast, superconductors are materials that do not create resistance and do not waste heat under suitable conditions.
The next tokamak model, the ST80, will utilize superconducting materials to generate a stronger and more efficient magnetic field for plasma control. Kelsall indicated that this model will be ready by 2026 or 2027. Following the ST80, researchers will begin work on the ST-E1, a commercial testing project aimed at demonstrating the technology’s ability to supply electricity to the grid. They hope to complete the project by the early 2030s.
