Fusion Science and Technology / Volume 61 / Number 2T / February 2012 / Pages 46-58
Fusion Machines / Proceedings of the Tenth Carolus Magnus Summer School on Plasma and Fusion Energy Physics / dx.doi.org/10.13182/FST12-A13492
Stellarators are toroidal devices where the required rotational transform of the magnetic field lines is generated by external field coils and not via an induced net toroidal plasma current. This confinement scheme has the advantages that, in principle, steady-state plasma operation is possible and that it does not have to brace itself against disruptions of a toroidal plasma current. At the cost of having to give up toroidal symmetry the properties of the stellarator field can be tailored to suit reactor needs. Research focuses on the plasma confinement properties of different stellarator fields and investigates the problems arising when one extrapolates to reactor parameters.