Accession Number : AD0666798

Title :   LASER SCINTILLATION CAUSED BY TURBULENCE NEAR THE GROUND.

Descriptive Note : Research rept. 1 Nov 63-30 May 66,

Corporate Author : MICHIGAN UNIV ANN ARBOR DEPT OF MATHEMATICS

Personal Author(s) : Portman, Donald J. ; Ryznar, Edward ; Waqif, Arif A.

Report Date : 1966

Pagination or Media Count : 85

Abstract : Laser scintillation was measured for a horizontal optical path 500 m long and 1 m high for various conditions of horizontally homogeneous turbulence. Wind direction, average vertical distributions of wind speed and temperature, and, in some cases, turbulent fluctuations of wind velocity were measured simultaneously. The results of the measurements were analyzed in relation to a set of theoretical relationships derived by Tatarski (1961) for electromagnetic wave propagation in turbulent flow. Tatarski's derivation of the scintillation frequency spectrum (at a point in a plane perpendicular to the optical path) in relation to the three-dimensional spectral density of index of refraction inhomogeneities is summarized and interpreted in relation to its validity for various conditions of turbulence. Analysis of the spectral data showed that their characteristics were similar to Tatarski's theoretical spectrum if the divergence of the laser beam, the size of the receiver aperture, the intensity of scintillation and turbulence spectra were considered. (Author)

Descriptors :   *SCINTILLATION), (*LASERS, (*ATMOSPHERIC MOTION, PROPAGATION), TURBULENCE, ATMOSPHERIC REFRACTION, DIFFRACTION, ATMOSPHERIC TEMPERATURE, COHERENT RADIATION, POLARIZATION, WIND, SPECTRUM SIGNATURES, THEORY, EXPERIMENTAL DATA.

Subject Categories : Atmospheric Physics
      Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE