Microwave scattering by inhomogeneous plasma column

The scattering features of microwave by inhomogeneous plasma column have been studied numerically by the Finite-difference-time-domain(FDTD) method and experimentally. The effects of the plasma frequency and electron collision rate on microwave's reflectance, transmittance and absorptance were tested. The results show the plasma column with plasma density of non-uniform distribution can make the scattering wave shift away from 0 to a side-angled direction. The electron density and the collision rate play an important role in the reduction of the wave reflection. The plasma density should be appropriate, even be lower than the critical value corresponding to the microwave, so that the microwave can reduce greatly in reflectance due to the strong scattering or absorption.