The dynamics of high intensity electron beam in the travelling wave structure is studied. The equation for self –consistent RF field are devised to the more general case in which the series resistance, wave phase velocity and damping coefficient are slowly varying functions of the longitudinal co-ordinate. Stationary solutions of nonlinear equations for RF field amplitude, for bunched beam ener...

Properties of six-component electromagnetic field solutions of a matrix form of the Maxwell equations, analogous to the four-component solutions of the Dirac equation, are described. It is shown that the six-component equation, including sources, is invariant under Lorentz transformations. Complete sets of eigenfunctions of the Hamiltonian for the electromagnetic fields, which may be interprete...

stress waves contain useful information about the properties of porous materials; they can be recovered through different non-destructive testing methods such as crosswell, vertical seismic profile, borehole logging as well as sonic tests. in all these methods, it is crucial to assess the effects of frequency on wave attributes including velocity and intrinsic attenuation. the dependency of per...

By applying a helical electric field along a plasma region, a revolving electron current is formed along the plasma and an elliptically polarized far-field terahertz wave pattern is observed. The observed terahertz wave polarization reveals the remarkable role of velocity retardation between optical pulses and generated terahertz pulses in the generation process. Extensive simulations, includin...

shear wave velocity (vs) data are key information for petrophysical, geophysical and geomechanical studies. although compressional wave velocity (vp) measurements exist in almost all wells, shear wave velocity is not recorded for most of elderly wells due to lack of technologic tools. furthermore, measurement of shear wave velocity is to some extent costly. this study proposes a novel methodolo...

OBJECTIVE To assess the reproducibility of time and frequency domain variables derived from the signal averaged P wave. DESIGN Longitudinal within patient study. SETTING Regional cardiothoracic centre. PATIENTS 20 patients (10 with documented paroxysmal atrial fibrillation and 10 normal controls) were studied on three occasions to assess the reproducibility of repeated signal averaged P w...

This paper studies the propagation of shear waves in a composite structure consisting of a piezoelectric layer perfectly bonded over a micropolar elastic half space. The general dispersion equations for the existence of shear waves are obtained analytically in the closed form. Some particular cases have been discussed and in one special case the relation obtained is in agreement with existing r...