Design and construction of the dipole magnet of the space plasma environment research facility (SPERF) for simulating the earth magnetosphere

A dipole magnet is designed in the SPERF to create the magnetic field for simulating the large-scale magnetosphere of the earth. The design and construction process of the dipole magnet is presented here to settle the issues in regard to electricity, vacuum, and support, etc. Several measures are taken to improve the magnet's insulation performance so as to meet the challenge imposed by a high voltage for achieving an intensive pulsed current. Meanwhile, to avoid influencing the plasma quality, a layer of Inconel is sprayed on the magnet's outer surface covered with a sawtooth-shaped sol-gel coat in advance. The designed magnet itself is validated by the measurement with respect to electrical properties, magnetic field, and cooling. In addition, a transition structure is proposed to transfer the intensive current from two coaxial cables to the leads of the magnet reliably. A supporting and motion mechanism is designed for the magnet to increase the flexibility of the magnetic field, and its strength is evaluated under the most severe condition. The dipole magnet design lays a foundation for the SPERF operation.