Low-Frequency Electromagnetic Shielding in a System of Two Coaxial Cylindrical Shells

In this work, the problem of shielding is examined for a system of two coaxial cylindrical shells, when the excitation is a current filament placed parallel to the axis of the cylinders either inside or outside them. For the calculation of the current density within the conducting material of the shells and the magnetic flux density in the different regions of the system, the diffusion equation for the magnetic vector potential is used. The incident field of the filament has a harmonic time variation, but the method can be applied to any time variation of the excitation by using a Laplace or Fourier transform.