Conclusion

The START project has shown that the spherical tokamak appears to behave at least as well as the conventional tokamak. It has similar operating regimes, confinement and stability but is resilient to the current-terminating major disruption and has a potentially useful "natural" exhaust system. Coupled with its simplicity and the substantial increase in efficiency, demonstrated by the trebling of the Tokamak world record value of ß achieved by START, there is every reason to continue research in this area. Inspired by START results, next-stage devices are being operated world-wide in order to further test the Spherical Tokamak concept. The MAST (Mega Amp Spherical Tokamak) experiment is now operating at Culham.

Poloidal field coils being modified
inside the START tank