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.
Its plasma volume is about 8 m3. Density ~ 1020/m3.
Image to right shows 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.