Tokamak Energy developing laser system to measure plasma density

Based near Oxford, the company aims to commercialise fusion energy through the combined development of spherical tokamaks with high temperature superconducting (HTS) magnets and utilising the hydrogen fuel combination of deuterium-tritium.

Tokamaks are based around a torus (a doughnut-shaped vacuum chamber) in which gaseous hydrogen is subjected to extreme heat and pressure until it becomes plasma.

Plasma temperatures inside a tokamak reach over 100 million degrees Celsius. The hydrogen fuel must be closely and accurately measured by a specialist laser system to keep the burning plasma stable, hold density and maintain fusion conditions.

The new laser-based dispersion interferometer system is currently being tested at Tokamak Energy’s Oxford headquarters before being installed on its ST40 fusion machine later this year.

In a statement, Dr Tadas Pyragius, Tokamak Energy plasma physicist, said: “Measuring plasma density is key to our understanding and control of the fusion fuel and efficient future power plant operations. A laser beam fired through the plasma interacts with the electrons and tells us the density of the fuel, which is essential for sustained fusion conditions and delivering secure and reliable energy to the grid.