Superconducting inserts in high-field solenoids

The critical currents of the innermost coil mainly limit the highest field of the present superconducting solenoids. For this reason, the insert coils in high-field solenoids are often wound with newly developed superconductors to increase their highest fields. This is a good demonstration of the high-field performance of the newly developed conductors. Design issues of high-field superconducting inserts are overviewed. Representative examples that have been carried out and are now in progress are introduced.