Shielding From External Magnetic Fields by Rotating Nonmagnetic Conducting Cylindrical Shells

The common strategy for reducing static and low-frequency magnetic fields in a specific region consists of surrounding the volume of interest with a layer of material with high magnetic permeability. However, if for some reasons, ferromagnetic materials are undesirable, rotating conducting nonmagnetic screens could be applied. In this paper, we discuss such a possibility in a quantitative way. Analytical solutions are obtained for infinitely long cylindrical shells rotating in a uniform, static, and time-harmonic external magnetic field. Useful simplified expressions for the shielding factors are given. Numerical results are shown for screens of finite length.