Toroidal Magnetic Field Configuration Produced by Multiply Linked Cusp Magnetic Fields

Abstract

We show that l=2 stellarator magnetic field configuration can be formed by superposition of a toroidal magnetic field and a series of toroidally linked cusp magnetic fields, which are successively rotated by forty-five degrees around the toroidal axis. The cusp field is generated by the current flowing in the opposite directions in a pair of rectangular coils facing each other. The proposed configuration has the following features ; i) the coil system is completely modular, ii) it allows easy access to the plasma, iii) a relatively large rotational transform is possible and iV) the aspect ratio can be made large, which implies possibility of high beta plasma confinement. Examples of the numerical calculation of magnetic surfaces are shown.