Comparison of 2-D Magnetic Designs of Selected Coil Configurations for the Next European Dipole (NED)

The next European dipole (NED) activity is developing a high-performance Nb₃Sn wire (aiming at a non-copper critical current density of 1500 A/mm² at 4.2 K and 15 T), within the framework of the Coordinated Accelerator Research in Europe (CARE) project. This activity is expected to lead to the fabrication of a large aperture, high field dipole magnet. In preparation for this phase, a working group on magnet design and optimization (MDO) has been established to propose an optimal design. Other parallel work packages are concentrating on relevant topics, such as quench propagation simulation, innovative insulation techniques, and heat transfer measurements. In a first stage, the MDO working group has selected a number of coil configurations to be studied, together with salient parameters and features to be considered during the evaluation: the field quality, the superconductor efficiency, the conductor peak field, the stored magnetic energy, the Lorentz forces and the fabrication difficulties. 2-D magnetic calculations have been performed, and the results of this comparison between the different topologies are presented in this paper. The 2-D mechanical computations are ongoing and the final stage will be 3-D magnetic and mechanical studies.