Design of Nonuniform Static Magnetic Compensation Coils for Magnetic Shielding Room

Near-zero magnetic environment serves as a fundamental research condition for multiple scientific fields. To obtain a large-scale and high-performance near-zero magnetic environment, this article presents a coil design method based on the boundary element method (BEM) for compensating the nonuniform static magnetic field existing in the magnetic shielding room (MSR). To achieve precise compensation of nonuniform magnetic field, BEM-based image method is introduced to eliminate the deviation by coupling between the magnetic field generated by the coil and the magnetic shielding material, and the gray wolf optimization (GWO) algorithm is employed for the optimal design of coils. The experimental results show that the coils designed by the method of this article can effectively compensate the nonuniform magnetic field distribution within a $100\times 100\times 100$ mm central area of the MSR. The range of the residual magnetic field has been reduced by 87.8%, thereby establishing an environment below 1 nT in the central area of the MSR. The proposed method will lay the foundation for the research of high-performance nonuniform magnetic compensation coils within the MSR.