Kinetic equation for a dense soliton gas

We propose a general method to derive kinetic equations for dense soliton gases in physical systems described by integrable nonlinear wave equations. The kinetic equation describes evolution of the spectral distribution function of solitons due to soliton-soliton collisions. Owing to complete integrability of the soliton equations, only pairwise soliton interactions contribute to the solution, and the evolution reduces to a transport of the eigenvalues of the associated spectral problem with the corresponding soliton velocities modified by the collisions. The proposed general procedure of the derivation of the kinetic equation is illustrated by the examples of the Korteweg-de Vries and nonlinear Schr?dinger (NLS) equations. As a simple physical example, we construct an explicit solution for the case of interaction of two cold NLS soliton gases.     

Nonlinear interaction of a circularly polarized electromagnetic wave with a dense laser plasma

The interaction of an intense circularly polarized laser pulse with a layer of plasma of supercritical density is studied. The nonlinear skin effect for the electromagnetic field and the coefficient of collisionless absorption of the laser pulse were calculated analytically. It is shown that, in the process of interaction with the plasma, the laser pulse generates solitons propagating through the plasma layer and transferring the radiation through the opaque medium. The coefficient of transparency of the plasma layer for the soliton-like penetration of the laser radiation was calculated. The plasma parameters at which the collisionless absorption is small as compared to the transformation of the laser energy into solitons were found.     

High-speed soliton transmission in dense periodic fibers

An 80-Gbit/s soliton can be transmitted over a cross-Pacific distance in a dense periodic fiber, even in the presence of higher-order effects. Such a dense dispersion-managed soliton is generally more stable and faces fewer mutual interactions than a conventional dispersion-managed soliton.     

Resonant interaction of an electromagnetic wave with an inhomogeneous plasma slab

Resonant interaction at oblique incidence of an electromagnetic wave on an inhomogeneous plasma slab is studied. The time evolution of this interaction is solved numerically from two-fluid equations, adiabatic equation for electron pressure and from Maxwell equations. It is shown that the electromagnetic energy of an incident wave is transformed both into the heat energy and into the energy of plasma oscillations in the direction of density gradient. The distribution of the transformed energy between the heat energy and the energy of plasma oscillations is strongly dependent on the plasma temperature. The ratio of heat energy to the energy of plasma oscillations is growing with growing temperature. The plasma oscillations are generated by magnetic induction of the penetrating wave. In a cold plasma they are generated especially in the overdense region and their frequency is equal to local plasma frequency. The electric field in the direction of plasma gradient has a form of a wave packet whose envelope reaches a maximum at resonance. The characteristic wavelength in the wave packet decreases and the amplitude of the packet increases with the time.     

Ion acoustic soliton experiments in a plasma

This paper reviews recent laboratory experiments on ion acoustic solitons that are excited, propagate, and interact in a plasma. The solitons can be described with the Korteweg–deVries (KdV) equation, the modified Korteweg–deVries (mKdV) equation, or the Kadomtsev–Petviashvilli (KP) equation. The results should be applicable in non- linear optics experiments.     

Thermodynamics of a dense plasma

Journal of Applied Spectroscopy -     

X-Ray diffraction from a dense plasma

We report measurements of x-ray scattering cross sections for dense plasmas created by subjecting aluminum foils to strong laser-driven shocks. A narrow cone of quasimonochromatic x-rays at approximately 4.75 keV was used to probe the shocked part of the foil and scattered photons were detected with a CCD camera. The scattering cross section shows a clear peak, indicating diffraction from the plasma. Analysis and simulation of the data suggest that radiative heating and electron-ion energy exchange are important factors in the plasma production.     

Ion acoustic soliton propagation in a magnetized relativistic plasma

Summary The Korteweg-de Vries equation for ion acoustic waves in the presence of weakly relativistic ion streaming velocity is derived in a magnetic plasma. It is found that relativistic effects are important in the solitary wave propagation for both fast and slow modes. Earlier results are reconfirmed. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

Possibility of the propagation of an electromagnetic soliton in a two-dimensional superlattice

A two-dimensional electron structure in a system with a periodic potential, i.e., a two-dimensional superlattice, is investigated. An equation is derived describing the propagation of an electromagnetic wave in a two-dimensional superlattice. It is shown that an electromagnetic soliton can propagate in a two-dimensional superlattice, where it is detectable experimentally because it can induce a pulsed entrainment current. The influence of an elliptically polarized (specified) electromagnetic wave on the form of the soliton is also investigated. It is shown that a solitary wave can be amplified under certain conditions. Fiz. Tverd. Tela (St. Petersburg) 39, 1470–1472 (August 1997)     

A two-dimensional soliton in a positive ion-negative ion plasma

The authors describe a series of experiments performed in a positive ion-negative ion plasma that were designed to study the reflection and focusing properties of solitons. The nonlinear wave was compared with a theoretical model using linear waves. The two-dimensional soliton was created by reflecting an incident planar soliton from a concave hemispherical surface. The experimental results are interpreted in terms of the linear waves that can exist in a focused Fabry-Perot resonator     

Resonant transmission of an electromagnetic pulse through a quantum well

The reflectance, transmittance, and absorbance of a symmetric electromagnetic pulse with a carrier frequency close to the frequency of direct interband transitions in a quantum well are calculated. The energy levels in the quantum well are assumed to be discrete, and two closely spaced excited levels are taken into account. The theory holds true for quantum wells of an arbitrary width at which the quantum confinement is retained. The calculations are performed with due regard for the difference between the refractive indices of the quantum well and the barriers. In this case, there appears an additional reflection from the quantum-well boundaries. The additional reflection results in a substantial change in the shape of the reflected pulse as compared to that characteristic of a homogeneous medium. The reflection from the quantum-well boundaries disappears at specific ratios between the carrier frequency of the exciting pulse and the quantum-well width.