Near-field scattering of finite cylindrical targets along the geomagnetic field in the anisotropic ionosphere

In the study of the scattering mechanism of very low frequency (VLF) waves on targets in the ionosphere, we propose a method for near-field scattering of VLF waves on finite-length conducting and dielectric cylinders in the ionosphere. Firstly, the scattering matrix under the excitation of electric and magnetic waves in the anisotropic ionosphere is analyzed by defining co- and cross-scattering coefficients; Then, based on the integral equation (IE) method and the method of moment (MoM), the semi-analytical expressions are obtained for near-field scattering and surface current of conducting and dielectric cylinder in the anisotropic ionosphere; Finally, by analyzing the characteristic waves of VLF waves in the anisotropic ionosphere, the spatial distribution of ordinary-waves (O-waves) and extraordinary-waves (E-waves) components are given in the near-field scattering of the scatterer. Numerical results indicate that VLF waves in the ionosphere excite different surface current on conducting and dielectric targets, which generates near-field scattering and coupled-scattering by different ionospheric environmental parameters, cylinder size, and incidence angles. Comparing current distribution and scattering components of O- and E-waves, the scattering mechanism between VLF waves and cylindrical targets exposed to uniform plasma is further revealed. The calculation method and results in this paper provide theoretical basis for scattering communication and target detection in the ionosphere.