Ion acoustic solitons in a relativistic warm plasma with densitygradient

Modified Korteweg-deVries equation (mK-dV), which governs the behavior of ion acoustic solitons in a relativistic warm plasma with density gradient, is derived. The electron inertia is also taken into account which is important when the streaming ions are present in the plasma. A solution of the mK-dV equation is obtained for the constant density gradient. When the ion acoustic soliton propagates into the lower plasma density region, its amplitude and energy increase, but the width decreases; the same is the case for the stronger density gradients     

Solitons in a relativistic plasma with negative ions

The interaction of the nonlinearity and the dispersiveness causing the solitary waves is studied in a relativistic plasma with negative ions through the derivation of a nonlinear partial-differential equation known as the Korteweg-de Vries equation. The negative ions play a salient part in the existence and behavior of the solitons and could be of interest in laboratory plasmas. First, the observations are made in a nonisothermal plasma, and later the reduction to the nonisothermality of the plasma shows entirely different characteristics as compared to the solitons in the isothermal plasmas. Comparison with the various solitons is emphasized     

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.     

Observation of Peregrine solitons in a multicomponent plasma with negative ions

The experimental observation of Peregrine solitons in a multicomponent plasma with the critical concentration of negative ions is reported. A slowly amplitude modulated perturbation undergoes self-modulation and gives rise to a high amplitude localized pulse. The measured amplitude of the Peregrine soliton is 3 times the nearby carrier wave amplitude, which agrees with the theory. The numerical solution of the nonlinear Schr?dinger equation is compared with the experimental results.     

Ion-acoustic wave in relativistic nonisothermal plasma with negative ions

We study solitary wave formation in a nonisothermal plasma with negative ions. When the ions are considered to be relativistic. The variations of the amplitude, width, and the phase velocity are obtained explicitly with respect to the ratio of the ion densities and the streaming velocity.     

弱相对论等离子体横向扰动下的离子声孤波

在低阶近似下，得到了描述无磁场相对论热离子等离子体的KP(Kadomtsev-Petviashvilli) 方程.研究表明，相对论热离子等离子中的非线性离子声孤波在高阶横向拢动下是稳定的， 且在相对论热离子等离子体中仅存在压缩型孤波. 关键词： 离子等离子体 孤波 声波 约化摄动法     

Ion-acoustic solitons and double-layers in a plasma consisting of positive and negative ions with non-thermal electrons

In this research paper, the authors have studied the properties of ion-acoustic solitons and double-layers in a plasma consisting of warm positive and negative ions with different concentration of masses, charged states and non-thermal electrons using small amplitude approximation. Reductive perturbation method is used to derive KdV and m-KdV equations. Existence of ion-acoustic solitons and double-layer is explored over a wide range of parameter space. The role of non-thermal electrons characterized by finite is investigated. It is observed that for a particular value of , there is a transition from compressive to rarefactive solitons. However, when is increased beyond a critical value, no double-layers are obtained. The significance of relative ion masses is also investigated.Received: 9 July 2004, Published online: 21 September 2004PACS: 52.35.-g Waves, oscillations, and instabilities in plasmas and intense beams     

On the envelope solitons in a relativistic ion-acoustic plasma

Summary Nonlinear Schr?dinger equation describing the envelope solitons is deduced in the case of ion-acoustic relativistic plasma, without taking recourse to the usual reductive perturbation theory. The methodology is that of Friedet al. (1973), which in some sense can be considered to be an extension of the effective (pseudo) potential theory. Amplitude and velocity of the solitary wave are obtained in terms of the physical parameters of plasma.

---

Riassunto Si deriva l'equazione di Schr?dinger non lineare che descrive i solitoni dell'involucro nel caso del plasma relativistico a onde ioniche, senza fare ricorso all'usuale teoria di perturbazione riduttiva. La metodologia è quella di Friedet al. (1973) che si può considerare in qualche modo come un'estensione della teoria efficace di (pseudo) potenziale. Si ottengono l'ampiezza e la velocità dell'onda solitaria nei termini dei parametri fisici del plasma.

---

Резюме Выводится нелинейное уравнение Шредингера, описывающее огибающие солитоны в случае релятивистской плазмы, без использования обычной теории возмущений. Методология аналогична методологии фрейда и др. (1973), которая в некотором смысле представляет обобщение теории эффективного (псевдо) потенциала. Получается вмплитуда и скорости одиночной волны в терминах физических параметров плазмы.

     

Ion acoustic shock waves in a relativistic electron-positron-ion plasmas

The Korteweg-de Vries-Burger (KdVB) equation is derived for ion acoustic shock waves in a weakly relativistic electron-positron-ion plasma. Electrons, positrons are considered isothermal and ions are relativistic. The travelling wave solution has been acquired by employing the tangent hyperbolic method. The vivid display of the graphical results is presented and analyzed. It is observed that amplitude and steepness of the shock wave decrease with increase of the relativistic streaming factor, the positron concentration and they increase with the increase of the coefficient of kinematic viscosity and vice versa. It is determined that at low temperature the shock wave propagates, whereas at very high temperature the solitary wave propagates in the system. The results may have relevance in astrophysical plasmas as well as in inertial confinement fusion plasmas.     

Dust-acoustic solitons in quantum plasma with kappa-distributed ions

Arbitrary amplitude dust-acoustic (DA) solitary waves in an unmagnetized and collisionless quantum dusty plasma comprising cold dust particles, kappa (κ)-distributed ions and degenerate electrons are investigated. The influence of suprathermality and quantum effects on the linear dispersion relation of DA waves is investigated. Then, the effect of κ-distributed ions and degenerate electrons on the existence domain of solitons is discussed in the space of (M, f). The comparison of the existence domain for higher and lower values of κ shows that suprathermality results in propagation of solitons with lower Mach number, and the quantum effects, lead to a higher values of Mach number. The existence domain of solitons for nondegenerate κ-distributed electrons is considered for comparison with effect of degenerate electrons. Also, we found that the Sagdeev potential well becomes deeper and wider as ε _F???i decreases, as for lower κ values, the influence of quantum effects on the Sagdeev pseudopotential profile is smaller.     

Kelvin-Helmholtz instability in a plasma with negative ions

A dispersion relation for low-frequency electrostatic modes in a plasma with negative ions is derived for the case in which a velocity shear Kelvin-Helmholtz instability exists in the positive ion flow along the magnetic field. It is found that the negative ions have, generally, a destabilizing effect, as seen previously for ion-acoustic and electrostatic ion-cyclotron waves. The influence of the negative-ion-to-positive-ion mass mass ratio on the stability is also examined     

Ion acoustic double layers in the vicinity of the critical velocity in a weakly relativistic plasma

Ion acoustic double layers in the vicinity of the critical velocity in a weakly relativistic plasma are found for the first time from a mixed form of the KdV and mKdV equations by the reductive perturbation method. It is shown to yield compressive and rarefactive double-layer profiles under certain conditions.     

Current generation in interaction between Langmuir solitons and a streaming plasma

A new mechanism for dc current and toroidal magnetic field generation is presented. This mechanism bases on the non-linear linear interaction between a high-frequency plasma soliton and a streaming plasma.     

Ion acoustic solitary waves in weakly relativistic plasma with nonthermal electron, positron and warm ion

The Korteweg-de Vries equation for a weakly relativistic ion acoustic wave propagating in oollisionless plasma containing nonthermal electron, positron and warm ion is derived. The effects of the ion temperature, nonthermal parameter and relativistic effect on the amplitude, width and energy of soliton are studied.     

Ion acoustic subharmonic excitation in a plasma

Ion acoustic subharmonic excitation in a plasma, with ion-neutral collision frequency greater than the frequency of excitation, is theoretically investigated. Two-fluid theory with source term is used to describe the system. The system exhibits either subharmonic excitation of orders 1/2 and 1/3, or subharmonic excitation of orders 1/3, 1/4 and 1/5. The resonance frequency range and the amplitude of second harmonic for each case is calculated. A comparison with experimental data can be used to obtain the values of the parameters describing the source term.     

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.     

Effect of electron inertia on KP solitons in a relativistic plasma

Propagation characteristics of KP solitons in a plasma with finite temperature ions drifting relativistically are investigated. With relativistically drifting ions the electron inertia is important and therefore the finite electron mass is included in the fluid equations instead of the usual Boltzmann distribution for obtaining the Kadomtsev–Petviashvili (KP) equation. Effect of the electron inertia and finite ion temperature is analyzed on the soliton characteristics.     

Ion acoustic solitons in magnetized collisional non-thermal dusty plasmas

The oblique propagation of ion-acoustic solitary waves (IASWs) is considered, in a magnetized non-thermal collisional dusty plasma, composed of non-Maxwelian κ-distributed electrons, inertial ions, and stationary dust. The reductive perturbation approach is adopted to derive the damped Korteweg de-Vries (dKdV) equation, and the dissipative oblique ion-acoustic wave properties are investigated in terms of different key plasma parameters via the numerical solution of the dKdV equation. The collisional effect, describing the ion-neutral collision in the plasma, is taken into account, and seen to influence the dynamics of IASWs significantly. The basic features of IASWs are observed to modify, and the polarity of the wave is seen to change due to the variation of dust to that of ion number density and also due to the variation of the supethermality index κ in the considered plasma system.     

Reflection of modified Korteweg-de Vries solitons in a plasmahaving negative ions

The variable coefficient modified Korteweg-de Vries (mKdV) equations for incident and reflected solitons are derived and solved to study the reflection of compressive and rarefactive ion acoustic solitons at the critical density in an inhomogeneous negative ion plasma. The polarity of the incident compressive and rarefactive solitons is not altered during the reflection process. Increasing the density gradient reinforces the reflection of both compressive and rarefactive mKdV solitons, whereas enhancement of the unperturbed plasma density weakens the reflection     

Formation of solitary structures and envelope solitons in electron acoustic wave in inner magnetosphere plasma with suprathermal ions

The propagation of electron acoustic solitary waves is investigated in magnetized two-temperature electron plasma with supra-thermal ion. By using the reductive perturbation technique, the Korteweg de-Vries (KdV) equation is derived. Later solving this equation, a solitary wave solution has been derived. These are mainly in astrophysical plasmas where changes of local charge density, temperature, and energy of particles produce considerable effects on the plasma system. The effects of supra-thermality, density, and Mach number on solitary structures are studied in detail. The results show that the supra-thermal index (κ) and ion to electron temperature ratio (σ) alters the regime where solitary waves may exist. While studying the solitary profile for different parametric variation some interesting conclusion can be drawn; it is shown that the solitary profile becomes flatter. This can be due to the thermal energy associated with the hot electrons. However, with the increase in ion density with respect to the cold electrons' density, the solitary waves become steeper and sharper. This is due to the comparatively heavier mass of ions. The density of cold electron also increases the solitary structures in a similar manner. The higher the density of cold electrons, sharper will be the profile. The above findings will be helpful in understanding many astrophysical phenomena and data obtained by space missions. For a further study, we keep the investigation of the formation of other kinds of stationary structures like shocks, double layers, etc.