The General Appearance of the Superconducting Magnet System for the Gas-Dynamic Multimirror Trap

Abstract

The paper presents the evaluation of basic parameters and general appearance of the superconducting magnet ic system of the Gas-Dynamic Multimirror Trap – the next-generation magnetic mirror research facility developed by the Budker Institute of Nuclear physics. The major requirements are that the magnetic field would be ramped up from 0.3 to 3 T within 5 seconds, which implies that a special low AC-loss superconducting cable must be chosen for this part of the magnet system. The mirror coils should have the field ∼12 T with an aperture exceeding typical of large-bore NMR magnets. In accordance with these requirements the optimized magnet system has been evaluated. The system can have modular design and consists of a set of 12 coils with NbTi superconductors and 4 coils made of Nb3Sn superconductor. Preliminary choice of superconducting cables and basic superconductors for the windings has been substantiated. The estimation of stability margins for all coils demonstrated that both NbTi and Nb3Sn coils have enough stability margins, including the operation of NbTi coils at fast changing current. The study demonstrated the feasibility of the optimized superconducting magnet system for the Gas-Dynamic Multimirror Trap with the use of modern low Tc superconductors and state-of-the-art superconducting magnet technologies.