ASA 126th Meeting Denver 1993 October 4-8

2aPAb1. On statistical fluctuations in single scattering by an ensemble of scatterers.

George H. Goedecke Michael De Antonio

Dept. of Phys., NMSU, Las Cruces, NM 88003-0001

Harry J. Auvermann

Army Res. Lab., Battlefield Environment Directorate, WSMR, NM 88002-5501

Expressions in terms of the presumed known scattering cross section of the objects are derived for the ensemble average single scattering differential cross section (sigma)[sub N] and its rms deviation (Delta)(sigma)[sub N] due to a homogeneous ensemble of N identical objects randomly positioned with no corrections in an observed volume V. For wavelength (lambda), it is well known that, if N(lambda)[sup 3]/V(less than or equal to)1, there is considerable diffuse scattering, while, if N(lambda)[sup 3]/V>>>1, the scattering is essentially forward and coherent. Apparently not so well known is the result of (Delta)(sigma)[sub N]/(sigma)[sub N] depends on another parameter (alpha)(identically equal to)C((theta))N((lambda)[sup 3]/V)[sup 4/3], when C((theta)) is a numeric of order unity and depends on scattering angle (theta). It is shown that, if (alpha)>>1, then (Delta)(sigma)[sub N]/(sigma)[sub N](alpha)N[sup -1/2] and is very small, while if (alpha)(less than or equal to)1, then (Delta)(sigma)[sub N](approximately equal to)(sigma)[sub N]. Application involving numerical simulation is made to single scattering of acoustic waves by an ensemble of turbules.