Design criteria for multilayer superconductive magnets

High current round composite conductors with superconductors near the surface are under development at the University of Wisconsin. The conductors are designed for single layer energy storage solenoids and possibly for solenoids with several layers. The radial and axial forces in such magnets are obtained by summing forces between turns. Solenoids with constant tension are achieved by changing the spacing between conductors in the axial direction. Multilayer solenoids are designed so that the tension in the different layers is the same as the required design value. This design value is chosen to make the conductors remain in tension. Constant tension designs facilitate the economic use of force-bearing structure in energy storage and fusion superconductive magnets.