Electromagnetic signal response to nonstationarity of bounded medium

Özet

Any time changing of medium features leads to transformation of electromagnetic signals propagating in this medium. This can be used for remote sensign of the medium. In this communication, a method is proposed that enables one to calculate the influence of medium nonstationarity on an electromagnetic signal. The method allows one to determine an electromagneticfield both inside and outside of a nonstationary medium. The specific realization of this method for a bounded dielectric, whose permittivity undergoes jumps changing in time, is demonstrated. As shown, the availability of a plane boundary nonstationary dielectric only leads to new effects in signal behavior and brings new information about medium features and the boundary. A peculiarity of the influnce of the permittivity jump changing on various eletromagnetic signals is shown also. Specifically, a plane monochromatic wave in the case of an oblique incidence on a boundary of dielectric, an electromagnetic radiation of a point source setting up out of a nonstationary medium and a short eletromagnetic video pulse being in the region of a nonstationary medium at the moment when the permitivity abruptly changes is considered.