Chanchal Bedi

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.

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...

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.

Higher order nonlinear effects on wave structures in a four-component dusty plasma with nonisothermal electrons

The higher order solutions of dust acoustic wave in dusty plasma consisting of positively charged warm adiabatic dust, negatively charged cold dust, and nonisothermally distributed electrons are studied. The Schamel–KdV equation is derived using reductive perturbation method (RPM). RPM is further extended to include the contributions of higher order terms and a generalized KdV equation is derived to observe the deviation from isothermality. Effects of nonisothermal parameter, mass and charge ratio, ratio of ion to electron temperatures, and ratio of dust to ion temperatures have been thoroughly studied. By using the renormalization method of Kodama and Taniuti [J. Phys. Soc. Jpn. 45, 298 (1978)], authors have also discussed characteristics of the dressed solitons.

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.

Study of envelope electron acoustic solitary waves under transverse perturbations having kappa distributed hot electrons

As is well known, the envelope electron acoustic (EA) nonlinear waves are expressed by nonlinear Schrodinger equation. In this paper, we find that under transverse perturbations, this kind of nonlinear waves can be described by Davey-Stewartson equation. In this work, modulational properties of EA wave and its stability regions in two-dimensional plasma have been studied.

Ion acoustic shock waves in weakly relativistic multicomponent quantum plasma

Ion acoustic Shock waves (IASWs) are studied in an collisionless unmagnetized relativistic quantum electron-positron-ion(e-p-i) plasma employing the quantum hydro -dynamic(QHD) model. Korteweg-deVries- Burger equation(KdVB) is derived using small amplitude perturbation expansion method to study the nonlinear propagation of the quantum IASWs. It is found that the coefficients of the KdVB equation are significantely modified by the positron density p, relativistic factor(Ur), temperatures σ, kinematic viscosity η and quantum factor(H).

Four component magnetized dusty plasma containing non-thermal electrons

Multicomponent plasmas are of great attraction for research in dusty plasmas. In the present research paper, dusty plasma consisting of non-thermal electrons, Maxwellian ions, negatively and positively charged warm adiabatic dust particles, is considered. The Korteweg-de Vries (KdV) equation which describes the basic features of the electrostatic solitary structures is derived by use of reductive perturbation method and solved for solitary wave solution. The effect of externally applied magnetic field and non-thermal electrons is found to modify the properties of the dust acoustic solitary potential significantly. The implications of these results for some space and astrophysical dusty plasma systems especially in planetary ring and cometary tails, are briefly mentioned.

Modulated wave packets in pulsar magnetospheric plasma

An investigation has been made of modulational instability of nonlinear ion acoustic wave in magnetized electron+positron+ion plasma. Three dimensional nonlinear Schrodinger equations (NLSE) is derived by using the standard reductive perturbation technique (RPT) to study the modulational instability. It is found that the coefficient of Nonlinear Schrodinger equation depends upon the positron to electron density ratio and the electron to positron temperature ratio. These coefficients significantly modify the conditions of the modulational instability.

Localized coherent nonlinear wave structures in dusty plasma with non-thermal ions

In the present research paper, the characteristics of dust-acoustic solitary waves (DASWs) and double layers (DLs) are studied. Ions are treated as non-thermal and variable dust charge is considered. The Korteweg–de Vries equation is derived using a reductive perturbation method. It is noticed that compressive solitons are obtained up to a certain range of relative density δ (= n i0 / n e0 ) beyond which rarefactive solitons are observed. The study is further extended to investigate the possibility of DLs. Only compressive DLs are permissible. Both DASWs and DLs are sensitive to variation of the non-thermal parameter.