Study On The Related Problems Of (Light) Beam Propagation In The Atmospheric Turbulence

In this paper, the fundamental theory about different atmospheric turbulence structure constant that determined by different turbulence model and different weather factors is introduced, which give a basis theory for the work of wave propagation in the turbulent media. According to the atmospheric turbulence structure constant of microwave and the modified Rytov method, the intensity scintillation index of microwave which propagates in level and slant path is derived and calculated. Based on the Ehrenfest's theory which the expectation value of the position of a particle moves in accordance with the classical laws of motion under the action of a force equal to the expectation value of the negative gradient of the potential, the variance of spot displacement and beam angle of arrival about Gaussian beam propagation in atmospheric turbulent are obtained. Meanwhile, the saturation condition of (light) beam wandering in strong turbulent media is given with focused and collimated Gaussian-beam waves for an example. In addition, by using the extended Huygens-Fresnel principle, the effects of atmospheric turbulence to the diffuse target are discussed. It shows that the variance of logarithm amplitude fluctuation in middle turbulent media is larger than unit, and both the distribution of the field and the intensity in receiver's are changed. Finally, by using the Rytov method and Born approximation, the diffuse target scattering problem is extended to the double slant path case, the intensity scintillation index on the plane of both target and receiver plane is investigated.