The Small Tight Aspect Ratio Tokamak, or START was a nuclear fusion experiment that used magnetic confinement to hold plasma.
The new shape increased efficiency by reducing the cost over the conventional design, while the field required to maintain a stable plasma was a factor of 10 less.
The main components that comprised START included the support structure, pulse transformer, vacuum tank, toroidal and poloidal field coils, and a limiter.
A graphite limiter was positioned around the central stainless steel tube and this provided a simple way to measure the innermost edge of the plasma during experiments.
These suspicions were further strengthened when the divertor coils were moved closer to the plasma in December 1996, which resulted in a higher frequency of disruptions.
[5]: 29 In March 1998, the START experiment finished and has since been disassembled and transferred to the ENEA research laboratory at Frascati, Italy, where it formed the basis of Proto-Sphera.
The START team began the Mega Ampere Spherical Tokamak Experiment or MAST in 1999 which operated in the Culham Science Centre, UK until 2013.