| | Spherical Tokamak advantages |
 | | The START (Small Tight Aspect Ratio Tokamak) experiment at Culham provided the world's first experimental results on hot spherical tokamak plasmas, achieving electron temperatures of more than 10 million °C. Keeping the plasma stable is vital for the efficiency of a fusion machine. |
| | A spherical tokamak or ST (sometimes called spherical torus) has a much tighter ring shape, more like a cored apple (illustrated by the inner shape in the figure). |
| | The toroidal magnetic field (supplied by the current flowing in the central column) needed to keep the plasma stable can be a factor of 10 less in a spherical tokamak than that of a conventional tokamak carrying the same plasma current. |
| www.fusion.org.uk /st/advantages.html (352 words) |
