START (Small Tight Aspect Ratio Tokamak)

There is increasing interest in the behaviour of tokamaks with tight aspect ratios, A (A=Ro/a), where toroidal effects become very important [ 1 ], World experience is of tokamaks with A>2.5, but recent theoretical studies predict that devices such as the ‘spherical torus’ reactor may have significant advantages in the search for economic fusion power. As yet however there are no experimental results with high temperature plasmas, in this area. START is specifically intended to study the physics behaviour at extremely tight aspect ratios, as low as 1.2.