Progress Report on the 43 T Hybrid Magnet of the LNCMI-Grenoble

A CEA-CNRS French collaboration is currently developing a new hybrid magnet to produce in a first step a continuous magnetic field of 43 T in a 34-mm warm bore aperture. This magnet combines a resistive insert, composed of Bitter and polyhelix coils, and a large bore superconducting “outsert.” The superconducting coil is based on the novel development of a Nb-Ti/Cu Rutherford Cable On Conduit Conductor (RCOCC) cooled down to 1.8 K by a bath of superfluid helium at atmospheric pressure. It aims at producing a nominal magnetic field of 8.5 T in a 1.1-m cold bore diameter. The specifications of the RCOCC will be presented together with the design and parameters of the cryogenic system. The solution to reduce the coupling between resistive and superconducting coils will be recalled as well as the constraints for designing the mechanical structure. The design study phase is coming to an end. The status of the conductor production and the next steps of the project are presented.