A. S. Bains

Modulational instability of ion-acoustic waves in a plasma with a q-nonextensive electron velocity distribution

The modulational instability (MI) of ion-acoustic waves (IAWs) in a two-component plasma is investigated in the context of the nonextensive statistics proposed by Tsallis [J. Stat. Phys. 52, 479 (1988)]. Using the reductive perturbation method, the nonlinear Schrodinger equation (NLSE) which governs the MI of the IAWs is obtained. The presence of the nonextensive electron distribution is shown to influence the MI of the waves. Three different ranges of the nonextensive q-parameter are considered and in each case the MI sets in under different conditions. Furthermore, the effects of the q-parameter on the growth rate of MI are discussed in detail.

Modulational instability of dust acoustic solitons in multicomponent plasma with kappa-distributed electrons and ions

In the present investigation the modulational instability (MI) of dust acoustic wave (DAW) in four-component dusty plasma consisting of negative and positive charged dust grains and kappa (κ) distributed electrons and ions is studied. Considering the multifluid plasma model and using the reductive perturbation technique, nonlinear Schrodinger equation, which governs the MI of DAW, is obtained. It is found that presence of positive dust component, kappa-distributed electrons (κe), ions (κi), and temperature ratio (σ) significantly modify the domain of the MI and localized envelope excitations. Further, the effects of these parameters on the growth rate of MI have also been discussed in detail.

Modulational instability of ion-acoustic wave envelopes in magnetized quantum electron-positron-ion plasmas

The amplitude modulation of quantum ion-acoustic waves (QIAWs) along an external magnetic field is studied in a quantum electron-positron-ion (e-p-i) magnetoplasma. Reductive perturbation technique ...

A nonlinear Zakharov-Kuznetsov equation in magnetized plasma with q-nonextensive electrons velocity distribution

By using the reductive perturbation method (RPM), a nonlinear Zakharov-Kuznetsov (ZK) equation for ion-acoustic solitary waves (IASWs) is derived for a magnetized plasma in which the electrons are nonextensively distributed. The combined effects of electron nonextensivity, strength of magnetic field, and obliqueness on the ion acoustic (IA) solitary profile are analyzed. Three different ranges of the nonextensive q-parameter are considered. It is observed that the system may support both compressive as well as rarefactive solitons. The magnetic field has no effect on the amplitude of solitary waves whereas the obliqueness affects both the amplitude as well as the width of the solitary wave structures.

Zakharov-Kuznetsov equation in a magnetized plasma with two temperature superthermal electrons

A nonlinear Zakharov-Kuznetsov (ZK) equation for ion-acoustic solitary waves (IASWs) in a magnetized plasmas containing kappa distributed cold and hot electrons is derived by using reductive perturbation method. From the solution of ZK equation, the characteristics of IASWs have been studied under the influence of various plasma parameters. Existence domain of physical parameters is determined. It has been observed that the present plasma system supports the existence of both positive as well as negative potential solitons. The combined effects of cold to hot electron temperature ratio (σ), density ratio of cold electrons to ions (f), superthermality of cold and hot electrons (κc,κh), strength of magnetic field (via Ωi), and obliqueness (θ) significantly influence the profile of IASWs. The physical parameters play a great role to modify the width and amplitude of the solitary structures. The stability analysis is also presented in this investigation and parametric range is determined to check the presence...

Ion acoustic soliton in weakly relativistic magnetized electron–positron–ion plasma

A theoretical investigation was made for the ion acoustic wave in a weakly relativistic magnetized electron-positron-ion warm plasma. A Korteweg-de vries equation (KdV) is derived by using a standard reductive perturbation method. It is found that the presence of ion temperature (σ), ratios of positron-to-electron density (β), electron-to-positron temperature (α), and relativistic factor (Ur) significantly modify solitonic behavior. The authors observed that these parameters considerably change the amplitude and width of the solitary wave.

Envelope excitations of ion acoustic solitary waves in a plasma with superthermal electrons and positrons

Theoretical studies of the nonlinear self-modulation of ion acoustic waves (IAWs) in an electron?positron?ion plasma with superthermal electrons are carried out. By using the standard reductive perturbation method (RPM), the nonlinear Schr?dinger equation (NLSE) is derived. The stability analysis, based on a nonlinear Schr?dinger-type equation, exhibits a wide instability region, which depends on spectral index (?), ratio of positron to electron density (p) and electron to positron temperature ratio (?). It is found that these parameters modify the nature of modulational instability (MI) for IAWs and associated envelope solitary structures. Further, the effect of these parameters on the growth rate of MI is discussed.

Modulational instability of ion-acoustic waves in plasma with a q-nonextensive nonthermal electron velocity distribution

Modulation instability of ion-acoustic waves (IAWs) is investigated in a collisionless unmagnetized one dimensional plasma, containing positive ions and electrons following the mixed nonextensive nonthermal distribution [Tribeche et al., Phys. Rev. E 85, 037401 (2012)]. Using the reductive perturbation technique, a nonlinear Schrodinger equation which governs the modulation instability of the IAWs is obtained. Valid range of plasma parameters has been fixed and their effects on the modulational instability discussed in detail. We find that the plasma supports both bright and dark solutions. The valid domain for the wave number k where instabilities set in varies with both nonextensive parameter q as well as non thermal parameter α. Moreover, the analysis is extended for the rational solutions of IAWs in the instability regime. Present study is useful for the understanding of IAWs in the region where such mixed distribution may exist.

Oblique ion-acoustic cnoidal waves in two temperature superthermal electrons magnetized plasma

A study is presented for the oblique propagation of ion acoustic cnoidal waves in a magnetized plasma consisting of cold ions and two temperature superthermal electrons modelled by kappa-type distributions. Using the reductive perturbation method, the nonlinear Korteweg de-Vries equation is derived, which further gives the solutions with a special type of cnoidal elliptical functions. Both compressive and rarefactive structures are found for these cnoidal waves. Nonlinear periodic cnoidal waves are explained in terms of plasma parameters depicting the Sagdeev potential and the phase curves. It is found that the density ratio of hot electrons to ions μ significantly modifies compressive/refractive wave structures. Furthermore, the combined effects of superthermality of cold and hot electrons κc,κh, cold to hot electron temperature ratio σ, angle of propagation and ion cyclotron frequency ωci have been studied in detail to analyze the height and width of compressive/refractive cnoidal waves. The findings in...

Two-dimensional envelope electron-acoustic waves under transverse perturbations

As is well known, the envelope electron-acoustic (EA) nonlinear waves in one dimension are governed by the nonlinear Schrodinger equation. If transverse perturbations are considered, then this type of nonlinear wave can be described by the general form of the Davey–Stewartson equation. In this work, modulational properties of EA wave and its stability regions in two-dimensional plasma have been studied.