The mesh-excited space charge wave of ion beam is observed to be amplified in a plasma, as the result of the reactivemedium instability. The amplification factor has the maximum value at the frequency corresponding to the synchronization condition between the beam wave and the lower hybrid wave mode of plasma, and then, an appreciable deceleration of beam is expected from the observation of the...

We describe a method of ultrashort-pulse and ultrafast-pulse-train generation through optical parametric amplification of a laser beat wave. Numerical simulation shows that 250-fs laser pulses at 1.55 lm are generated from a beat-wave seeded optical parametric amplifier pumped by a 30-ps laser at 1064 nm. The pulse compression is attributable to sideband generation and parametric amplification ...

1 Abstract Interaction of external monochromatic, linearly polorized plane EM-wave with nonlinear one-dimensional wake wave, generated by relativistic electron bunch moving in cold plasma, is considered. At definite conditions on parameters of plasma and bunch, nonlinear wake wave can have a pronounced spikes, where plasma electron density has its maximum value and plasma electron velocities ar...

1 Abstract Interaction of external monochromatic, linearly polorized plane EM-wave with nonlinear one-dimensional wake wave, generated by relativistic electron bunch moving in cold plasma, is considered. At definite conditions on parameters of plasma and bunch, nonlinear wake wave can have a pronounced spikes, where plasma electron density has its maximum value and plasma electron velocities ar...

tehran, the capital of iran, is under the threat of large magnitude earthquakes (above 7) located on known active faults. previous studies on the effect of local surface geology on earthquake ground motion using 1d calculation of sh transfer function (jafari et al., 2001; jica & cest, 2000) and using experimental methods (haghshenas, 2005) based on earthquake and ambient noise vibration recordi...

The explanation of wave behavior upon total internal reflection from a gainy medium has defied consensus for 40 years. We examine this question using both the finite-difference time-domain (FDTD) method and theoretical analyses. FDTD simulations of a localized wave impinging on a gainy half space are based directly on Maxwell's equations and make no underlying assumptions. They reveal that ampl...

PURPOSE To test rigorously the hypothesis that the a-wave of the electroretinogram (ERG) is proportional to the rod photocurrent by examining the applicability to a-waves of a recent model of the activation steps in the G-protein cascade of phototransduction. METHODS ERGs were recorded in response to flashes of graded intensity, from six dark-adapted normal subjects and from two patients, one...

The gravitational wave equations form a parametric resonance system during oscillatory reheating after inflation, when cast in terms of the electric and magnetic parts of the Weyl tensor. This is in direct analogy with preheating. For chaotic inflation with a quadratic potential, this analogy is exact. The resulting amplification of the gravitational wave spectrum begins in the broad resonance ...

Although microvascular disease is a hallmark of systemic sclerosis (SSc), a higher prevalence of macrovascular disease and a poorer related prognosis have been reported in SSc than in the general population. The simultaneous assessment of prognostically relevant functional properties of larger and smaller arteries, and their effects on central hemodynamics, has never been performed in SSc using...