Divergent Diffraction Research Articles

Weakly divergent ray and diffraction beams in oceanic waveguides

Conditions that should be satisfied by the sound velocity profile of an oceanic waveguide for the dependence of the ray cycle length on the ray phase velocity to contain smooth extrema are formulated. The extrema correspond to weakly divergent ray beams forming “caustic” beams. It is found that diffraction effects cause a considerable smoothing of the sharp extrema that occur in the dependence of the interference period of neighboring modes on their phase velocity. As a result, in addition to the weakly divergent ray beams, weakly divergent diffraction beams and the corresponding “diffraction” caustics can be formed.

SIMULATION STUDY OF DIVERGENT BEAM X-RAY DIFFRACTION BY CRYSTALS

Acoording to the crystal symmetry, diffraction geometry and the diffraction laws, the complicated divergent beam X-ray diffraction has been studied. A method for simulating such diffraction is described. The computer generated pseudo-Kossel line patterns are exactly consistent with those recorded in experiment and the indices of all diffraction lines in the patterns can be identified. A set of standard divergent diffraction diagrams related to 〈100〉, 〈110〉 and 〈111〉oriented Si single crystals are completed successfully by computer.