Accession Number : AD0649806

Title :   ELECTROMAGNETIC SCATTERING FROM ABSORBING SPHERES,

Corporate Author : SOUTHWEST CENTER FOR ADVANCED STUDIES DALLAS TEX

Personal Author(s) : Kattawar,George W. ; Plass,Gilbert N.

Report Date : 28 DEC 1966

Pagination or Media Count : 46

Abstract : An efficient method for the calculation of Mie cross sections for absorbing particles is discussed. It is used to calculate an extensive set of curves which illustrate the dependence of the efficiency factors Q for absorption, scattering, and extinction on the size parameter x and on n1 and n2 (the real and imaginary parts of the index of refraction). Among the interesting features shown are the following: (1) as n2 increases, Q(sca) decreases to a minimum value before increasing, when x > or = 1 and for most values of n1; (2) the maximum value of Q(ext) at the first resonance decreases rapidly when a small amount of absorption is introduced; (3) over a considerable range of the parameters the width of the first resonance of Q(ext) is proportional to (n1) to the -4th power when there is no absorption and to (n2n1) to the -2nd power when there is absorption; (4) when n1>>1, the scattered intensity near the first resonance is predominately forward, symmetrical, or predominately backward when x is respectively somewhat smaller than, equal to, or larger than the resonance value; (5) as n2 increases, the forward scattered intensity first increases before it decreases, when x > or = 1 and for most values of n1; (6) the half-width of the angular intensity function varies as 1/x when x > or = 10 and is relatively insensitive to the value of n1 and n2. (Author)

Descriptors :   (*ELECTROMAGNETIC RADIATION, SCATTERING), (*SPHERES, REFRACTIVE INDEX), ABSORPTION, PARTICLES, FUNCTIONAL ANALYSIS, NUMERICAL ANALYSIS

Subject Categories : Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE