skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Scattering by rotationally symmetric anisotropic spheres: Potential formulation and parametric studies

Abstract

Vector potential formulation and parametric studies of electromagnetic scattering problems of a sphere characterized by the rotationally symmetric anisotropy are studied. Both {epsilon} and {mu} tensors are considered herein, and four elementary parameters are utilized to specify the material properties in the structure. The field representations can be obtained in terms of two potentials, and both TE (TM) modes (with respect to r) inside (outside) the sphere can be derived and expressed in terms of a series of fractional-order (in a real or complex number) Ricatti-Bessel functions. The effects due to either electric anisotropy ratio (A{sub e}={epsilon}{sub t}/{epsilon}{sub r}) or magnetic anisotropy ratio (A{sub m}={mu}{sub t}/{mu}{sub r}) on the radar cross section (RCS) are considered, and the hybrid effects due to both A{sub e} and A{sub m} are also examined extensively. It is found that the material anisotropy affects significantly the scattering behaviors of three-dimensional dielectric objects. For absorbing spheres, however, the A{sub e} or A{sub m} no longer plays a significant role as in lossless dielectric spheres and the anisotropic dependence of RCS values is found to be predictable. The hybrid effects of A{sub e} and A{sub m} are considered for absorbing spheres as well, but it is foundmore » that the RCS can be greatly reduced by controlling the material parameters. Details of the theoretical treatment and numerical results are presented.« less

Authors:
; ; ;  [1];  [2]
  1. Department of Electrical and Computer Engineering, National University of Singapore, Kent Ridge, Singapore 119260 (Singapore)
  2. (France)
Publication Date:
OSTI Identifier:
21072389
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics; Journal Volume: 75; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevE.75.026609; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; BESSEL FUNCTIONS; DIELECTRIC MATERIALS; ELECTROMAGNETIC RADIATION; PARAMETRIC ANALYSIS; PERMITTIVITY; POTENTIALS; SCATTERING; SPHERES; VECTORS

Citation Formats

Qiu, C.-W., Li, L.-W., Yeo, T.-S., Zouhdi, Saied, and Laboratoire de Genie Electrique de Paris, Ecole Superieure D'Electricite, Plateau de Moulon 91192, Gif-Sur-Yvette, Cedex. Scattering by rotationally symmetric anisotropic spheres: Potential formulation and parametric studies. United States: N. p., 2007. Web. doi:10.1103/PHYSREVE.75.026609.
Qiu, C.-W., Li, L.-W., Yeo, T.-S., Zouhdi, Saied, & Laboratoire de Genie Electrique de Paris, Ecole Superieure D'Electricite, Plateau de Moulon 91192, Gif-Sur-Yvette, Cedex. Scattering by rotationally symmetric anisotropic spheres: Potential formulation and parametric studies. United States. doi:10.1103/PHYSREVE.75.026609.
Qiu, C.-W., Li, L.-W., Yeo, T.-S., Zouhdi, Saied, and Laboratoire de Genie Electrique de Paris, Ecole Superieure D'Electricite, Plateau de Moulon 91192, Gif-Sur-Yvette, Cedex. Thu . "Scattering by rotationally symmetric anisotropic spheres: Potential formulation and parametric studies". United States. doi:10.1103/PHYSREVE.75.026609.
@article{osti_21072389,
title = {Scattering by rotationally symmetric anisotropic spheres: Potential formulation and parametric studies},
author = {Qiu, C.-W. and Li, L.-W. and Yeo, T.-S. and Zouhdi, Saied and Laboratoire de Genie Electrique de Paris, Ecole Superieure D'Electricite, Plateau de Moulon 91192, Gif-Sur-Yvette, Cedex},
abstractNote = {Vector potential formulation and parametric studies of electromagnetic scattering problems of a sphere characterized by the rotationally symmetric anisotropy are studied. Both {epsilon} and {mu} tensors are considered herein, and four elementary parameters are utilized to specify the material properties in the structure. The field representations can be obtained in terms of two potentials, and both TE (TM) modes (with respect to r) inside (outside) the sphere can be derived and expressed in terms of a series of fractional-order (in a real or complex number) Ricatti-Bessel functions. The effects due to either electric anisotropy ratio (A{sub e}={epsilon}{sub t}/{epsilon}{sub r}) or magnetic anisotropy ratio (A{sub m}={mu}{sub t}/{mu}{sub r}) on the radar cross section (RCS) are considered, and the hybrid effects due to both A{sub e} and A{sub m} are also examined extensively. It is found that the material anisotropy affects significantly the scattering behaviors of three-dimensional dielectric objects. For absorbing spheres, however, the A{sub e} or A{sub m} no longer plays a significant role as in lossless dielectric spheres and the anisotropic dependence of RCS values is found to be predictable. The hybrid effects of A{sub e} and A{sub m} are considered for absorbing spheres as well, but it is found that the RCS can be greatly reduced by controlling the material parameters. Details of the theoretical treatment and numerical results are presented.},
doi = {10.1103/PHYSREVE.75.026609},
journal = {Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics},
number = 2,
volume = 75,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • No abstract prepared.
  • We present a class of exact cosmological solutions of Einstein-Maxwell equations, which are anisotropic and spatially homogeneous of Bianchi types VIII and IX, and class IIIb in the Stewart-Ellis classification of locally rotationally symmetric models. If we take the electromagnetic field equal to zero, a class of Bianchi types VIII/IX spatially homogeneous anisotropic cosmological solutions with perfect fluid is obtained.
  • In a crossed molecular beam experiment, time-of-flight distributions of oD/sub 2/ molecules scattered from Ar have been measured in a center-of-mass angular range from 50/sup 0/ to 100/sup 0/ at a collision energy of E = 85 meV. The data show clearly resolved 0..-->..2 rotational transitions of D/sub 2/ in the backward direction. From a combined analysis of these inelastic cross sections and the measured total differential cross sections for D/sub 2/+Ar at E = 83 meV, the complete repulsive potential surface is derived. Comparison with the potential which LeRoy and Carley determined from spectroscopy shows that the repulsive partmore » of its anisotropic V/sub 2/ term is steeper, whereas the isotropic parts V/sub 0/ agree within the experimental error. A combined analysis of the present inelastic scattering data and the original spectroscopic data yields an improved version of the three-dimensional stretching-dependent potential surface of LeRoy and Carley. Cross sections calculated from the semiempirical ''HFD'' potentials reported by Tang and Toennies and by Rodwell and Scoles are also fairly close to experiment, with the latter potential performing somewhat better than the former. The comparison with other hydrogen molecule--rare gas interactions reveals a maximum in the effective strength of the repulsive anisotropy for Ne--H/sub 2/ and a nearly complete conformality of the reduced V/sub 0/ and V/sub 2/ terms to each other for He, Ne, and Ar--H/sub 2/.« less
  • The anisotropic interaction potential for Ne-D/sub 2/ is determined by a direct inversion method from the measured rotationally inelastic j=0 ..-->.. j=2 and elastic j=0 ..-->.. j=0 differential cross sections. The values obtained yield the repulsive part of the interaction in the range 2.43 to 2.77 A. This is the first inversion of inelastic scattering data. The method is restricted to weak inelastic systems. It is computationally simple, and involves only errors of approx. 5% in the inverted potential.