UK engineers tame fusion plasma in spherical tokamak for first time

A team of scientists at the UK Atomic Energy Authority (UKAEA) has achieved a significant breakthrough in fusion energy research by successfully stabilizing plasma in a spherical tokamak for the first time. Using Resonant Magnetic Perturbation (RMP) coils, they applied a small 3D magnetic field at the plasma edge inside the MAST Upgrade tokamak, located at the Culham Centre for Fusion Energy in Oxfordshire. This method completely suppressed Edge Localised Modes (ELMs), instabilities that occur at the plasma edge and can damage tokamak components or degrade performance. This achievement demonstrates that advanced plasma control techniques used in conventional tokamaks can be adapted to compact spherical tokamaks, which are promising for future fusion power plants. The breakthrough addresses one of the key challenges in fusion energy—maintaining plasma stability at the extremely high temperatures and pressures required for fusion reactions. The findings from MAST Upgrade’s fourth scientific campaign will directly inform the design of ELM control systems for the UK’s