Plasma in the MAST reactor. Note the almost circular outer profile of the plasma. The extensions off the top and bottom are plasma flowing to the ring diverters, a key feature of modern tokamak designs.
It was fully commissioned by EURATOM/UKAEA and took two years to design and a further two years to construct. It includes a neutral beam injector similar to that used on START and uses the same merging compression technique instead of the conventional direct induction. Merging compression provides a valuable saving of central solenoid flux, which can then be used to further ramp up the plasma current and/or maintain the required current flat-top.
The device is planning a major upgrade to significantly enhance its capabilities to address its primary objectives (listed below).