Accession Number:

ADA222757

Title:

Scattering and Nonscattering Obstacles

Descriptive Note:

Corporate Author:

ILLINOIS UNIV AT CHICAGO CIRCLE DEPT OF MATHEMATICS

Personal Author(s):

Report Date:

1983-08-01

Pagination or Media Count:

15.0

Abstract:

Two problems of Helmholtzs equation for a wave incident on an obstacle are considered. For the first, the scattering problem, the obstacles response satisfies Sommerfelds outgoing wave radiation condition, and the net radiative response is positive for the second, the response satisfies a standing wave condition an appropriate combination of outgoing and incoming waves such that the net radiative response is zero. The essential features of the solutions are exhibited in terms of amplitude functions g the usual scattering amplitude and g, and the interrelation of the functions are stressed in the derivation of integral equations gg introduced earlier in multiple scattering contexts. The scattering amplitude g is always complex, but the simpler function g is shown to be imaginary for nonabsorbing obstacles having inversion symmetry. Long-wavelength approximations for g may be obtained from potential theory and perturbation procedures, and corresponding approximations for g then follow from gg. jhd

Subject Categories:

  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE