A method to quantitatively regulate the magnetization state of magnetic shielding devices for reducing the static residual field

Abstract Magnetic shielding devices isolate the geomagnetic field with high-permeability soft magnetic materials. Researchers adopted an external compensation method to further reduce the static residual field. A common method is to apply a continuous DC compensation magnetic field outside the shielding layers to offset the geomagnetic field. The active approach aims to create a weak magnetic field environment. The prolonged intervention of the DC compensation system raises the energy consumption and increases the instability factors of the residual field. In this study, a method to quantitatively regulate the magnetization state of a magnetic shielding device is proposed, which is achieved with a short-duration regulation magnetic field generated by external compensation coils. This enhances the ability of the magnetic shielding device to resist the geomagnetic field. The waveform of the regulating magnetic field is designed based on the source analysis and variation model of the residual field. This is verified by a single-layer cubic magnetic shielding device. The results reveal that the static residual field at the center point and within the test region decreased by 86% and 57.7% compared with the initial value; moreover, the energy consumption and the stability of residual field are improved compared to the DC compensation method.