APPLICATION DE LA MÉTHODE DE SOMMATION DE FAISCEAUX GAUSSIENS AU CALCUL DU CHAMP SONORE DIFFRACTÉ PAR UN ÉCRAN EN ATMOSPHÈRE INHOMOGÈNE

The method of summation of Gaussian beams is an effective method for the computation of scalar wave fields (and vector fields) in high frequency approximation [1,2,3]. This method is free of certain ray-tracing artifacts (infinitely high energy at caustics, perfect shadows) with the same computing cost. But, this method is not convenient for problems where there are rays tangent to the boundaries or where the boundaries have angular points. However, associated with the concept of the Geometrical Theory of Diffraction, it is possible to build a solution for the fields diffracted by an angular point. At this point, the incident field induces a cylindrical wave which can be decomposed in a set of gaussian beams. This method has been applied to the case of diffraction of the screen on the ground in the presence of downward refraction. The theory is compared with controlled measurements made indoors above a curved surface with a screen