Research On The Problems Of Waves Propagation And Scattering In The Atmospheric Turbulence

In this paper, the traditional Rytov method and the Markov approximation method are summarily discussed, in a weakly atmospheric turbulence and in a strong or saturated one, respectively. According to the traditional Rytov method, The theory model of modified Rytov method is given for plane wave and spherical wave propagation in the atmospheric turbulence, and the characters of optical scintillation for waves propagation along horizontal paths is studied, the inner scale effect is considered, especially. Then, the results, calculated by the modified Rytov method, is compared with the experiment measurement, it shows that the modified method is suitable in moderate atmospheric turbulence. According to the theory of optical wave propagation in the slant path and the ITU-R turbulence structure constant model, which is altitude dependent and proposed in 2001, the modified Rytov method is extended to be applied to study on the problems, which waves propagate in the slant path. The scintillation index as a function of the Rytov variance is obtained from weak to strong fluctuation regions with plane wave and sphere wave incidence, respectively. The influence of the parameters, such as inner scale, wind speed, is studied. In the end, the theory of fractal geometry is applied to the waves propagation and scattering in atmospheric turbulence, and the first and second order moments of the scattering fields are derived by considering the effects of the fractal atmospheric turbulence. The normalized back-scattering radar cross section of a perfectly conducting disk is calculated. The influence of fractal dimension of atmospheric turbulence on the radar cross section is analyzed.