A relativistic theory for two-stream free electron laser (FEL) with a one-dimensional helical wiggler and ion-channel guiding in the presence of self-fields are presented. A dispersion relation (DR) which includes coupling between the electromagnetic and the electrostatic waves is derived from a fluid model, with all of the relativistic terms related to the transverse wiggler motion. This DR is...

Non-linear interactions among the inertial modes of a rotating fluid can be described by a network of coupled oscillators. We use such a description for an incompressible fluid to study the development of the r-mode instability of rotating neutron stars. A previous hydrodynamical simulation of the r-mode reported the catastrophic decay of large amplitude r-modes. We explain the dynamics and tim...

in investigation of dynamic specifications of castellated beams, it is necessary to be studied the excitation intensity of dynamic mode shapes for different loading conditions. it is evident that for a specific loading, not all modes of a structure are excited and the structural response depends on the applied loading specifications. in this paper using the finite element method (based on ansys...

A family from Iraq with five growth hormone deficient children in two closely related sibships is reported. The clinical forms and modes of inheritance of familial growth hormone deficiency are discussed briefly.

We study the viscosity corrections to the growth rate of nucleating bubbles in a slightly supercooled first order phase transition in 1 + 1 and 3 + 1 dimensional scalar field theory. We propose a microscopic approach that leads to the non-equilibrium equation of motion of the coordinate that describes small departures from the critical bubble and allows to extract the growth rate consistently i...

recent years have brought a great deal of expansion to the economic systems of developing countries. although they serve as vital link of economic activities, the transportation network of these countries have not grown proportionally. since transportation investments is a a substantial portion of the national budget, a good knowledge of each mode's various characteristics is essential, wh...