Computer simulation of the propagation of a plane electromagnetic wave in a waveguide formed by the Earth's surface and the ionosphere under the condition of inhomogeneous boundary conductivity

The article presents the results of computer simulation of the propagation of a plane electromagnetic wave. Lightning discharges are natural sources of pulsed electromagnetic radiation (atmosphere). Atmospheric propagates in the Earth-Ionosphere waveguide as a plane electromagnetic wave with a wide frequency spectrum with an intensity maximum in the range of 4-10 kHz. After earthquakes with magnitudes of the order of 7 or more, the saturation of groundwater with secondary minerals increases, which leads to a local increase in the conductivity of the earth in these areas. What determines the electrophysical properties of the earth, as the parameters of the lower boundary of the Earth-Ionosphere waveguide. Which affect the characteristics of electromagnetic waves propagating in the waveguide. It is assumed that, by studying the parameters of the atmosferic, it is possible to establish the presence of an inhomogeneity in the conductivity of the waveguide wall. Based on the system of Maxwell equations with boundary conditions in the form of a Perfectly matched layer, a mathematical model of the process is set. The boundary conditions of the model determine the region of propagation of an electromagnetic broadband signal as a waveguide with inhomogeneous boundary conductivity. The system of model equations is solved by the numerical Finite-Difference Time-domain method. In order to solve the problem and conduct computer modeling, a software package was developed in MATLAB environment. In order to verify the assumption, a number of computer simulations were carried out. As a result, it is shown that there is a backscattering of electromagnetic wave on the waveguide trace, arising as a consequence of reflection of the wave in its interaction with the inhomogeneity of the conductivity of the lower boundary of the waveguide. It is shown that with the help of mathematical modeling of the process of atmospheric propagation and its interactions with inhomogeneity in the waveguide it is possible to establish the presence of inhomogeneity and its relationship to the characteristics of radiation.