Existence Of Ion-acoustic Solitary Waves Research Articles

Ion-acoustic solitary, breathers, and freak waves inadegenerate quantum plasma

In this investigation, the characteristics of ion acoustic (IA) solitary, breathers, and freak waves have been examined by using spin evolution quantum hydrodynamic model in a degenerate quantum plasma consisting of inertial non-degenerate ions and degenerate electrons with spin-up and spin-down states. The Korteweg–de Vries (KdV) equation is derived by employing reductive perturbation technique and its solution is determined to see the existence of IA solitary waves. Only positive potential solitary structures are formed. Further, using appropriate transformation, the KdV equation is transformed into nonlinear Schrödinger equation (NLSE) and its different order solutions are used to study the characteristics of breathers such as the Akhmediev breather, the Kuznetsov–Ma breather and freak waves. Further, the formation of super order of freak waves has also been explored. The influence of different plasma parameters including density polarization ratio has been investigated on the characteristics of IA solitary waves and different types of breathers. It is observed that the density polarization ratio has a strong influence on the characteristics of different types of nonlinear structures. The present investigation may be of great importance to provide physical insight to understand nonlinear dynamical processes in dense astrophysical regions such as white dwarfs and neutron stars.

Analytical study on the existence of ion-acoustic solitary waves in a plasma consisting of warm streaming ions and nonthermal electrons

Theoretical investigations have been made for the formation of ion-acoustic solitary wave structure in a plasma consisting of warm streaming positive ions and nonthermal electrons. Analytical solutions have been obtained with some sufficient and necessary conditions for the existence of ion-acoustic solitary waves. Some critical values of the ion temperature and the nonthermal parameter of electrons have been obtained and presented graphically. It is shown that drift of the ions and the nonthermal electrons have significant effects on the formation of ion-acoustic solitary waves. In presence of the streaming motion of the ions, two distinct modes (fast and slow) of propagation have been obtained. Limiting values of the soliton speed for these modes have been calculated. It is found that the drift motion and ion temperature change significantly the conditions for the existence and properties of ion-acoustic solitons.

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.

Ion-acoustic solitary waves and their interaction in a weakly relativistic two-dimensional thermal plasma

This paper discusses the existence of ion-acoustic solitary waves and their interaction in a weakly relativistic two-dimensional thermal plasma. Two Korteweg–de Vries equations for small but finite amplitude solitary waves in both ξ and η directions are derived. The phase shifts and trajectories of two solitary waves after the collision with an arbitrary angle α are also obtained. The effects of parameters of the normalized ion temperature σ, the ratio of heat capacity δ, the relativistic factor Fγ, and the colliding angle α on the amplitudes, the widths and the phase shifts of both the colliding solitary waves are studied. The effects of these parameters on the new nonlinear wave created by the collision between two solitary waves are examined as well. The results suggest that these parameters can significantly influence the amplitude, the width of the newly formed nonlinear wave and the colliding solitary waves. The phase shifts of the colliding solitary waves strongly depend on the colliding angle α. Moreover, there are compressive solitary waves in such a system.

An analytical study of ion-acoustic solitary waves in a plasma consisting of two-temperature electrons and warm drift ions

Propagation of ion-acoustic waves in a multicomponent plasma consisting of warm positive ions with stream velocity and two-temperature electrons has been theoretically investigated. New analytical solutions with sufficient and necessary conditions are obtained for the existence of ion-acoustic solitary waves in the plasma. It is seen that the drifting ions and two temperature electrons have key roles on the formation of ion-acoustic solitary waves in a multicomponent plasma. The critical values of the ion temperature and phase velocity of the solitary waves have been numerically estimated, which would be applicable to various physical situations.

On the existence of ion-acoustic solitary waves in a gravitating dusty plasma having charge fluctuation

Theoretical investigation on the propagation of ion-acoustic waves in an unmagnetized self-gravitating plasma has been made for the existence of solitary waves using the reductive perturbation method. It is observed that nonlinear excitations follow a coupled third-order partial differential equation which is slightly different from the usual case of coupled Korteweg-de Vries (K-dV) system. It appears that the system so deduced is a two-component generalization of the previous one derived by Paul et al. (1999) in which it was shown that ion-acoustic solitary waves can not exist in such system.

Effect of electron inertia on the speed and shape of ion-acoustic solitary waves in plasma

Conditions for the existence of ion-acoustic solitary waves are investigated in a cold collisionless plasma taking into account the electron inertia. The Sagdeev’s pseudopotential is derived in terms of u, the ion velocity. It is found that there exists a critical value of u0(≠0), the value of u at which (u′)2=0, beyond which the soliton solution ceases to exist and the electron inertia plays a non-insignificant role in determining this critical value. This result reproduces the result of Johnston and Epstein [Phys. Plasmas. 7, 906 (2000)] when the effect of electron inertia is neglected.