SMES solenoids with reduced stray field

In order to reduce the stray held of common thin walled solenoids that are used for SMES applications various methods were examined. A second solenoidal coil with the opposite dipole moment was placed within the other coil. Configurations in a single plane were regarded only. The amount of stored energy was given. Calculation methods have been found that yield the minimum geometrical dimensions. In addition, methods that determine whether the configuration can be constructed with ordinary superconductors were developed. Finally it was shown that these configurations are able to reduce the stray field remarkably compared to a common single coil solenoid.>