Characteristic Of Electromagnetic Wave Passing Through The Heated F-Region

Communication through the ionosphere has gradually become integral in human activities, such as radio, television, wireless communication, global positioning system(GPS) and navigation because of the development in science and technology. The propagation of electromagnetic wave in the ionosphere, which can be significantly affected by artificial heating of the ionosphere, has attracted much attention. The propagation characteristics of electromagnetic wave in the ionosphere are investigated using ray tracing method and ionospheric heating model. The main topics and results of the study are as follows:1. The background and significance of the study on ionospheric heating effects and electromagnetic wave propagation in the heated ionosphere are briefly described. The importance of ionospheric heating in civil and military technology is discussed.2. Numerical simulation model of the ionosphere based on the ionospheric heating theory is established according to the variation in the electron density, momentum equation, and energy conservation equation. Oblique ionospheric heating was numerically simulated with different heating time or different heating power based on background of the IRI-2012 and neutral atmospheric model MSIS-90. Thus the influence of heating time and heating power of ionospheric heating on the electron density and electron temperature disturbance is evaluated.3. A variable step size ray tracing model for propagating of electromagnetic waves in the ionosphere is established, by utilizing the numerical calculation method of Runge-Kutta, based on the ray tracing Haselgrove’s equations and known background ionosphere electron density gradient. Propagation path of electromagnetic waves is drawn according to the proposed ray tracing model. These paths in different kinds of ionospheric environment, such as the normal case, case with sporadic E region, and case with heated F region are compared. Thus, the influence of sporadic E and F regions on the propagation of electromagnetic waves in the ionosphere is presented.4. Multipath of electromagnetic waves in the ionosphere is introduced. Then, the derivation of mathematical expressions for transmission loss, absorption loss, and reflection loss of electromagnetic waves in the ionosphere is presented. The influences of the vertical motion of the ionosphere, the vertical motion of the heated F region, variation in the electron density in the ionosphere, and change in the geomagnetic field on the Doppler shift are analyzed. Finally, echo effect of the wave in the ionosphere is simulated by computer.5. Irregularity scattering theory of electromagnetic waves in the heated F region is introduced. Then the electromagnetic scattering of electromagnetic waves in the ionosphere with the heated F region is simulated based on this theory. Results provide a theoretical guidance for the quantitative analysis of scattering of electromagnetic waves in irregularity.