Accession Number : ADA116938

Title :   Toward an Increased Understanding of the Singularity Expansion Method.

Descriptive Note : Final rept.,

Corporate Author : R AND D ASSOCIATES MARINA DEL REY CA

Personal Author(s) : Sancer,M I ; Varvatsis,A D

PDF Url : ADA116938

Report Date : Dec 1980

Pagination or Media Count : 92

Abstract : Four separate efforts related to the singularity expansion method (SEM) are described in this report. Two of the efforts deal with acoustic scattering and two deal with electromagnetic scattering. The rationale for treating acoustic scattering is that useful inferences can be drawn from the results obtained to enhance our understanding of electromagnetic scattering. The first acoustic scattering effort was to establish that important theoretical results valid for electromagnetic SEM are also valid for scalar (acoustic) SEM. In the process of accomplishing this task, an interesting relationship was established between the interior Dirichlet and exterior Neumann problem. This relationship is viewed as the scalar analogue of the pseudosymmetric argument developed for electromagnetic SEM. The remaining scalar scattering effort consisted of an additional theoretical development that established the relationship between scalar SEM theory and a prominent scattering theory. A by-product of the second effort is a formal proof that SEM poles are simple. One of the two electromagnetic SEM subjects treated in this report is a continued study of an old question concerning the class of coupling coefficient issue that exists in electromagnetic SEM. The remaining subject is a numerical study that demonstrates the dependence of the numerically determined electromagnetic SEM pole locations on aspects of the procedure employed to find them. (Author)

Descriptors :   *Electromagnetic scattering, *Acoustic scattering, *Electromagnetic pulses, *Numerical analysis, Coupling(Interaction), Boundaries, Dirichlet integral, Coefficients, Scalar functions, Expansion, Spheres, Eigenvalues, Magnetostatics

Subject Categories : Numerical Mathematics
      Acoustics
      Electromagnetic Pulses

Distribution Statement : APPROVED FOR PUBLIC RELEASE