Interaction Of Ion-acoustic Solitary Waves Research Articles

Oblique Interaction of Ion-Acoustic Solitary Waves in e-p-i Plasmas

In this study, we investigate the oblique collision of two ion-acoustic waves (IAWs) in a three-species plasma composed of electrons, positrons, and ions. We use the extended Poincare-Lighthill-Kuo (PLK) method to derive the two-sided Korteweg-de-Vries (KdV) equations and Hirota’s method for soliton solutions. The effects of the ratio (δ) of electron temperature to positron temperature and the ratio (p) of the number density of positrons to that of electrons on the phase shift are studied. It is observed that the phase shift is significantly influenced by the parameters mentioned above. It is also observed that for some time interval during oblique collision, one practically motionless composite structure is formed, i.e., when two ion-acoustic waves with the same amplitude interact obliquely, a new non-linear wave is formed during their collision, which means that ahead of the colliding ion-acoustic solitary waves, both the amplitude and width are greater that those of the colliding solitary waves. As a result, the nonlinear wave formed after collision is a new one and is delayed. The oblique collision of solitary waves in a two-dimensional geometry is more realistic in high-energy astrophysical pair plasmas such as the magnetosphere of neutron stars and black holes.

Effect of nonthermal distributed electrons and temperature on phase shifts during the collision of inward and outward ion-acoustic solitary waves in nonplanar geometry

Interaction of nonplanar ion-acoustic solitary waves is an important source of information for studying the nature and characteristics of ion-acoustic solitary waves (IASWs). The head-on collision between two cylindrical/spherical IASWs in un-magnetized plasmas comprising of nonthermal distributed electrons and warm ions is investigated using the extended version of Poincare–Lighthill–Kuo (PLK) perturbation method. How the interactions are taking place in cylindrical and spherical geometries are shown numerically. Analytical phase shifts are derived for nonplanar geometry. The effects of the ion to electron temperature parameter and the nonthermal electrons parameter on the phase shift are studied. It is shown that the properties of the interaction of IASWs in different geometries are very different.

The effects of nonthermality on the interaction of ion-acoustic solitary waves in a plasma consisting of warm adiabatic ions and nonthermal electrons

An investigation has been made on the head-on collision of two ion-acoustic solitary waves in an unmagnetized nonthermal plasma whose constituents are warm adiabatic ions and nonthermally distributed electrons. The extended Poincaré–Lighthill–Kuo perturbation method is used to derive the Korteweg–de Vries equations for both compressive and rarefactive ion-acoustic solitary waves in this plasma system. The effects of the ion to electron temperature ratio σ and the nonthermality of the electron distribution α on the interaction and structure of the colliding solitary waves are investigated. It is found that these factors, especially α, can significantly modify the properties of the waves and their collisions, and that the collisions for the two types of solitary waves are very different. It is also important to note that the phase shifts induced by the collision of compressive and rarefactive solitary waves are also different. The relevance of this investigation to the observations in astrophysical plasmas as well as experimental plasmas with nonthermally distributed electrons is briefly pointed out.

Propagation and interaction of ion—acoustic solitary waves in a quantum electron—positron—ion plasma

This paper discusses the existence of ion-acoustic solitary waves and their interaction in a dense quantum electronpositron—ion plasma by using the quantum hydrodynamic equations. The extended Poincaré—Lighthill—Kuo perturbation method is used to derive the Korteweg-de Vries equations for quantum ion—acoustic solitary waves in this plasma. The effects of the ratio of positrons to ions unperturbation number density p and the quantum diffraction parameter He (Hp) on the newly formed wave during interaction, and the phase shift of the colliding solitary waves are studied. It is found that the interaction between two solitary waves fits linear superposition principle and these plasma parameters have significantly influence on the newly formed wave and phase shift of the colliding solitary waves. The investigations should be useful for understanding the propagation and interaction of ion-acoustic solitary waves in dense astrophysical plasmas (such as white dwarfs) as well as in intense laser-solid matter interaction experiments.

The effects of Bohm potential on ion-acoustic solitary waves interaction in a nonplanar quantum plasma

The interaction of ion-acoustic solitary waves (IASWs) in a nonplanar unmagnetized quantum plasma consisting of electrons, positrons, and ions are studied by employing the quantum hydrodynamic model and the Korteweg-de Vries description. We provide the theoretical predictions about the phase shifts for the compressive IASWs and the rarefactive IASWs collisions, respectively. The effects of the positron to electron Fermi temperature ratio, the positron to ion number density ratio, and the quantum Bohm potential on phase shift are investigated. It is found that these factors can significantly modify the properties of the IASWs collisions. In particular, we find that the variations of phase shifts with quantum Bohm potential for two types of IASWs are apparently different. The validity of the results of present study is also pointed out.

Propagation and head-on collisions of ion-acoustic solitons in a Thomas–Fermi magnetoplasma: Relativistic degeneracy effects

Small amplitude propagation and quasielastic head-on collision of ion-acoustic solitary waves (IASWs) are investigated in a degenerate Thomas–Fermi electron-positron-ion magnetized plasma using extended Poincaré–Lighthill–Kuo reductive perturbation method for both ultrarelativistic and nonrelativistic electron/positron degeneracy cases. It is observed that both bright- and dark-type solitary shapes can exist in such plasma, depending on two critical values. The shape of ion-acoustic solitary structures as well as sign of their collision phase shifts are both determined by the same critical values. It is further revealed that relativistic degeneracy of electrons/positrons has significant effect on the propagation as well as interaction of IASWs.

Propagation and Interaction of Ion-Acoustic Solitary Waves in a Two-Dimensional Plasma Consisting of Isothermal Electrons and Hot Ions

We study the propagation and interaction of ion-acoustic solitary waves in a simple two-dimensional plasma by using the extended Poincaré–Lighthill–Kuo perturbation method. We consider the interaction between two ion-acoustic solitary waves with different propagation directions in such a system, and obtain two Korteweg-de Vries equations for small but finite amplitude solitary waves along both ξ and η trajectories. The effects of the ratio of ion temperature σ, the ratio of heat capacity γ and the colliding angle α. on the amplitude, the width of the new nonlinear wave created by the collision between two solitary waves are studied. The effects of these parameters on both the colliding solitary waves are examined as well. It is found that all the above-mentioned parameters have significant effects on the properties of these nonlinear waves.

The interaction of ion-acoustic solitary waves in a two-dimensional hot ion plasma

Using the extended Poincar-Lighthill-Kuo perturbation method, we study the interaction between two ion-acoustic solitary waves with different propagation directions in a two-dimensional hot ion plasma, and obtain two KdV equations for solitary waves in both ξ and η directions. We also obtain the phase shifts and trajectories after the collision of two solitary waves with an arbitrary angle. The effects of the ratio of ion temperatures σ, the ratio of heat capacities γ and the angle α on the phase shifts are studied. The results suggest that these parameters can significantly influence the phase shift of the solitary waves. Moreover, there are compressive solitary waves in such a system.

Formation and Interaction of Ion-Acoustic Solitary Waves in a Collisionless Warm Plasma

The formation and interaction of solitary waves in a warm-ion, hot isothermal electron plasma have been studied with the Vlasov equation for ions and Boltzmann distribution for electrons. An arbitrary initial potential pulse having a width smaller (or larger) than that of a solitary wave decomposes into one (or several) solitary wave(s) with (or without) ion-acoustic oscillations behind. In the interaction of two solitary waves, it has been found that: (1) If the initial amplitude ratio is not too large, the two waves exchange their amplitudes and bounce apart; (2) if the initial amplitude ratio is large, the larger wave first absorbs the smaller, subsequently re-emits it behind. A steady-state solitary wave solution for the ion fluid equations with a scalar pressure and Boltzmann electrons presents a smaller width and a larger velocity than the solution of the Korteweg-de Vries equation with the same amplitude. The limiting Mach number is smaller than Sagdeev's value.