Applied Scientific Research, Section B 

About: Applied Scientific Research, Section B is an academic journal. The journal publishes majorly in the area(s): Magnetic field & Boundary value problem. It has an ISSN identifier of 0365-7140. Over the lifetime, 454 publications have been published receiving 3968 citations.

A modification of cagniard’s method for solving seismic pulse problems

Abstract: A modification of Cagniard’s method for solving seismic pulse problems is given. In order to give a clear picture of our method, two simple problems are solved, viz. the determination of the scalar cylindrical wave generated by an impulsive line source and the scalar spherical wave generated by an impulsive point source.

Impedance boundary conditions for imperfectly conducting surfaces

Abstract: It is shown how the exact electromagnetic boundary conditions at the surface of a material of large refractive index can be approximated to yield the usual impedance or Leontovich boundary conditions. These conditions relate the tangential components of the electric and magnetic fields (or the normal components and their normal derivatives) via a surface impedance which is a function only of the electromagnetic properties of the material. They are valid for surfaces whose radii of curvature are large compared with the penetration depth, and also for materials which are not homogeneous but whose properties vary slowly from point to point. As the refractive index (or conductivity) increases to infinity, the conditions go over uniformly to the conditions for perfect conductivity.

Electromagnetic scattering from a radially inhomogeneous sphere

Abstract: The generalization of the Lorenz-Mie theory for scattering from a homogeneous sphere to a radially inhomogeneous sphere is given. In this case, the scatterer consists of a spherical body with any number of concentric homogeneous regions. The treatment makes use of the analogy with non-uniform transmission line theory.

Guided electromagnetic waves in anisotropic media

Abstract: The propagation of guided waves in anisotropic media has recently become of interest in two fields, viz. in the interpretation of ferromagnetic resonance experiments and in the construction of microwave fourpoles which violate the reciprocity relation. In both cases we are faced with the solution of Maxwell’s equations in a volume which is enclosed by perfectly conducting walls and.which is completely or partially filled with a medium whose magnetic permeability is described by a second order tensor. An account is given here of some work, both theoretical and experimental, on this subject. Chapter I is an introduction, containing a short survey of the theory of guided waves in isotropic media and of the problems arising in anisotropic media, together with a historical synopsis. Chapter II gives a general formulation of the theory of guided waves in anisotropic media, comprising the existing theories, and also deals with some new applications. In Chapter III a cavity technique for measuring Faraday rotations is described which has several advantages over older techniques. In Chapter IV experimental results obtained for the series of Ferroxcubes IVA, B, C, D, E are collected. Chapter V finally deals with the physical interpretation of these results. In particular the experimental data are compared with Rado’s theory of the permeability tensor in non-saturated ferromagnetics.

Far field scattering from bodies of revolution

Abstract: By use of approximations based on physical reasoning radar cross-section results for bodies of revolution are found. In the Rayleigh region (wavelength large with respect to object dimensions) approximate solutions are found. Examples given include a finite cone, a lens, an elliptic ogive, a spindle and a finite cylinder. In the physical optics region (wavelength very small with respect to all radii of curvature) Kirchhoff theory and also geometric optics can be used. When the body dimensions are only moderately large with respect to the wavelength, Fock or Franz theory can be applied, and examples of the circular and elliptic cylinder are presented. In the region where some dimensions of the body are large with respect to the wavelength and other dimensions are small with respect to the wavelength, special techniques are used. One example, the finite cone, is solved by appropriate use of the wedge-like fields locally at the base. Another example is the use of traveling wave theory for obtaining approximate solutions for the prolate spheroid and the ogive. Other results are obtained for cones the base perimeter of which is of the order of a wavelength by using known results for rings of the same perimeter.