Optimal design of uniform magnetic field coils within irregular magnetic shielding based on coupled SNOPT-finite element method analysis

Abstract The highly uniform magnetic field coil is one of the most important components of miniaturized atomic inertial sensors. However, the development of the magnetic field model of coils in magnetic shielding with irregular shapes is difficult in practice. In this study, an optimization method for the design of coil structure parameters based on hybrid modelling with the finite element method and the SNOPT algorithm was proposed. The finite element method was used to characterize the geometric structure of the magnetic shield accurately and incorporate the characteristic B-H parameters of the material into the optimization model to improve the design accuracy. The three-dimensional model was reduced to two dimensions, and the parameters of the coil structure were optimized by an intelligent algorithm, which improved the solution efficiency. The effectiveness of the proposed approach was demonstrated by optimizing the design of a solenoid coil inside the cylindrical magnetic shielding with holes and stovepipes, which reduced the design error caused by the magnetic leakage flux.