Three-Dimensional Scattering and Inverse Scattering from a Disturbed Region in Planarly Layered Cold Unmagnetized Plasma Media

We apply the forward scattering and inverse scattering algorithms to a cold unmagnetized plasma region within a multilayered background medium. Each layer has a different plasma frequency. The disturbed region in the plasma has an arbitrary shape, so it is an electromagnetic wave scatterer and can exist in any layer. The stabilized biconjugate-gradient fast Fourier transform (BCGS-FFT) algorithm is used to compute the scattered field. The scattered fields calculated by the BCGS-FFT yield excellent agreement with simulated results from the commercial software. In the inverse scattering process, the variational Born iterative method is used to reconstruct the relative permittivity, and thus the plasma frequency of the disturbed region. Multiple frequencies are adopted to determine the dispersive property of the plasma medium.