Subscale stress-managed asymmetric common coil design

Abstract

In the context of the high-field magnet program, the Swiss Accelerator Research and Technology initiative is dedicated to researching and developing robust, high-field accelerator magnets for the future circular collider. As part of this initiative, the PSI team successfully designed, prototyped, and tested the first subscale stress-managed Nb3Sn common coil dipole magnet with enhanced training behavior. Following this accomplishment, a proposal was made for a stress-managed asymmetric common coil design for improved field quality, compatible with the requirements of accelerator magnets. This work follows the conceptual methodology proposed by PSI and details the electromagnetic and thermal design of a subscale asymmetric common coil magnet, equipped with a ferromagnetic yoke. The influence of the iron yoke on the magnet's field quality is analyzed and optimized according to the specified nominal current. A cooling strategy is proposed that involves cooling the windings using pipes carrying a fluid under forced flow, with the pipes in contact with the conductor. An alternative option, where the yoke is cooled to a higher temperature using a second fluid, is also considered. The magnet protection is analyzed considering an energy extraction system