An FDTD formulation for communication through a plasma with a linear density profile

A finite-difference time-domain (FDTD) formulation employing an nonlinear bulk velocity of electron is studied and applied to analysis of multiple electromagnetic wave propagation in an unmagnetized and cold plasma layer with a linearly increasing electron density profile. The formulation is suitable for studying the performance of communication through plasma sheath in re-entry or hypersonic vehicle. Resonant absorption of electromagnetic wave and its angle dependency in plasma sheath are analyzed using the developed formulation. Gradient pressure of linear bulk velocity of the electron and distortion of the electron density are applied to the nonlinear correction of electromagnetic wave propagation. The nonlinear interaction of two incident waves and scattering process are investigated. Scattering wave captured at the vehicle shows that high frequency pump wave launched at the vehicle is modulated by low frequency signal wave transmitted from ground. The result is analogous to the Raman scattering process and can be applied to show the feasibility of communication through high density plasma sheath.