Substantial advances have been made in the design of stellarator configurations to satisfy physics properties and fabrication feasibility requirements for experimental devices. However, reactors will require further advances in configuration design, in particular with regard to maintenance and operational characteristics, in order to have high availability. The diamagnetic properties of bulk high temperature superconductor (HTS) material can be used to provide simple mechanisms for magnetic field-shaping by arranging them appropriately in an ambient field produced by relatively simple coils.

A stellarator configuration has been developed based on this concept. A small number of toroidal field coils carrying appropriate current would be sufficient to create a background toroidal field. Discrete HTS monoliths (“pucks” or “tiles”) are placed on a shaped structure that can be split in the poloidal direction at arbitrary locations. This allows modular stellarators to be designed with large openings that provide access to remove interior plasma facing components, no longer restricted by highly shaped back legs of the modular coil winding. Unlike a coil, the structure can be assembled and disassembled in pieces of convenient size, facilitating maintenance.

Calculations of the effect of the use of monoliths for field modification in stellarators and tokamaks will be described.