Travelling wave in a helical wave guide is considered for electron acceleration. A first determination of the travelling wave modes using a partial wave expansion (PWE) and a point matching method is presented. It gives a rapid solution for moderate deformation of the guide relative to a straight cylinder. Strong deformations will give higher accelerating gradient but the PWE diverges. Two meth...

the orthogonality of the valence and core states can be violated if there are semicore states which leak out of the muffin-tin sphere. The only way to avoid the breakdown of the orthogonality is to include these semicore states as valence states. Singh ' recently proposed two ways to do this. In his first proposal he includes, in addition to the usual ul and i I radial basis functions at the va...

An exact analytical solution is obtained for the scattering of electromagnetic waves from a plane wave with arbitrary directions of propagation and polarization by an aggregate of interacting homogeneous uniaxial anisotropic spheres with parallel primary optical axes. The expansion coefficients of a plane wave with arbitrary directions of propagation and polarization, for both TM and TE modes, ...

optical interferometry is being used as an efficient tool to analyse smooth surfaces for more than a century. although, due to introduction of novel computer assisted analyzing techniques and array detectors, like ccd, the speed and the precision of processing have been increased tremendously, but the main equation involved is not changed. the main equation is the intensity distribution in the ...

Recently it was shown that the exact cosmological solutions known as the vacuum plane-wave solutions are late-time attractors for an open set of the spatially homogeneous Bianchi universes containing a non-inflationary γ-law perfect fluid. In this paper we study inhomogeneous perturbations of these plane-wave spacetimes. By using expansion-normalised scale-invariant variables we show that these...

A highly dispersive dual-concentric-core pure silica photonic crystal fiber is designed with a maximum chromatic dispersion value of about -9500 ps/(nm km) around the 1.56 microm wavelength region and a full width at half-maximum (FWHM) of 55 nm. The change in the dispersion-bandwidth product as a function of period is carefully studied by using the plane wave expansion method. The coupled mode...

This paper is concerned with the effect of pure shear on the reflection from a plane boundary of infinitesimal plane waves propagating in a half-space of incompressible isotropic elastic material. For a special class of constitutive laws it is shown that an incident plane harmonic wave propagating in the considered plane gives rise to a surface wave in addition to a reflected wave (with angle o...

In this paper, we study two different Graded Index (GRIN) photonic crystal (PC) structures which are named as structure type I and type II. The PC structures are made of the square rod in an air background. To design a GRIN PC structure the lattice constant has been altered in the direction transverse to propagation. We investigated focusing effect             and waveguiding behavior of electr...

In the theories of electrodynamics, acoustics, and optics, fields that satisfy the homogeneous wave equation are often represented by integral expansions of monochromatic plane waves, all propagating with the same speed [ 1,2] . Two different plane-wave expansions are in use. One expansion, due to Whittaker [3] , expresses the field as a superposition of monochromatic, homogeneous plane waves; ...