The finite-difference-time-domain (FDTD) method is applied to simtdate the twodimensional propagation of electromagnetic TM (S-polarization) mode in atmospheric plasma and in metal layer for strong electron-neutral collisions. Dependence of the wave attenuation on both plasma parameters and incident wave angle are obtained. It is indicated that for a given electron density profile the attenuation depends strongly on the incident angle, the wave frequency, the width of plasma layer, and the collision frequency between electrons and neutrals.
The longitudinal plasmons are the electrostatic collective excitations of the solidelectron gas.In this paper,the dispersion relations of these plasmons for one-,two- and three-dimensional electron gas are compactly derived in two approaches with uniform disturbed Coulombpotentials.The first approach is adopted usually in solid state theory that is the so-called randomphase approximation (RPA) with the Lindhard dielectric function in the long-wavelength andhigh-frequency limits.The second method is a typical plasma fluid description that includes theelectron fluid equations with the adiabatic process in the jellium model.The disturbed electrostatic(Coulomb) potential produced by the oscillation of electron density is dimensionally dependentand derived from the Poisson equation in Appendix B.
A two-dimensional metal model is established to investigate the stealth mechanisms of radar absorbing material(RAM)and plasma when they cover the model together.Using the finite-difference time-domain(FDTD)method,the interaction of electromagnetic(EM)waves with the model can be studied.In this paper,three covering cases are considered:a.RAM or plasma covering the metal solely;b.RAM and plasma covering the metal,while plasma is placed outside; e.RAM and plasma covering the metal,while RAM is placed outside.The calculated results show that the covering order has a great influence on the absorption of EM waves.Compared to case a,case b has an advantage in the absorption of relatively high-frequency EM waves(HFWs), whereas case c has an advantage in the absorption of relatively low-frequency EM waves(LFWs). Through the optimization of the parameters of both plasma and RAM,it is hopeful to obtain a broad absorption band by RAM and plasma covering.Near-field attenuation rate and far-field radar cross section(RCS)are employed to compare the different cases.
When an electromagnetic(EM)wave propagates in an atmospheric pressure plasma(APP)layer,its attenuation depends on the APP parameters such as the layer width,the electrondensity and its profile and collision frequency between electrons and neutrals.This paper proposesthat a combined parameter-the product of the line average electron densityand width d ofthe APP layer(i.e.,the total number of electrons in a unit volume along the wave propagationpath)can play a more explicit and decisive role in the wave attenuation than any of the aboveindividual parameters does.The attenuation of the EM wave via the product of and d withvarious collision frequencies between electrons and neutrals is presented.