UK's MAST Upgrade Completes Fifth Campaign, Sets Record Plasma Pressure

UKAEA announced on August 6, 2026 that its MAST Upgrade spherical tokamak at Culham completed its fifth experimental campaign, generating more than 1,100 plasmas and achieving the highest plasma pressure in the machine's history without destabilization. The team suppressed Edge Localised Modes (ELMs) — disruptive plasma bursts that can damage reactor walls — through four independent methods, including a world-first demonstration of using 3D magnetic coils to stabilize the plasma edge. Researchers also accessed four stable high-performance operating regimes (including QH-mode and I-mode) and developed a world-first real-time plasma position control technique using deuterium light measurements. Two additional neutral beam injectors and an Electron Bernstein Wave heating system are being added through 2027, ahead of a sixth campaign in 2028 focused on STEP-relevant research.