Harvinder Kaur

Ion-acoustic solitons in a plasma consisting of positive and negative ions with nonisothermal electrons

In this research paper, the authors study the propagation of ion-acoustic solitons in a plasma consisting of warm positive and negative ions with different concentration of masses, charged states, and nonisothermal electrons. To account for the full nonlinearity of plasma equations, a quasipotential method is used here. The potential so obtained is characterized for solitons as a function of Mach number, positive and negative ions temperature, nonisothermal electrons, different concentration of negative and positive ions over a wide range of parameter space. Corresponding to isothermal case with β=1, coexistence of compressive and rarefactive solitons is obtained. For non-negative β≠1, only compressive solitons are observed. The prediction, that with introduction of negative ions there exists a critical ion concentration below which compressive solitons exist and above which rarefactive solitons exist, is ruled out for nonisothermal electrons.

Higher order solutions to ion-acoustic solitons in a weakly relativistic two-fluid plasma

The nonlinear wave structure of small amplitude ion-acoustic solitary waves (IASs) is investigated in a two-fluid plasma consisting of weakly relativistic streaming ions and electrons. Using the reductive perturbation theory, the basic set of governing equations is reduced to the Korteweg–de Vries (KdV) equation for the lowest order perturbation. This analysis is further extended using the renormalization technique for the inclusion of higher order nonlinear and dispersive effects for better accuracy. The effect of higher order correction and various parameters on the soliton characteristics is investigated and also discussed.

Dust-acoustic solitary waves in a finite temperature dusty plasma with variable dust charge and two temperature ions

In this paper, the characteristics of dust-acoustic solitary waves in dusty plasma are studied. Dust charge and temperature are treated as variables. The authors have used the pseudopotential method to investigate the possibility of compressive as well as rarefactive solitons. An expression for the pseudopotential has been derived. The pseudopotential is a function of the Mach number, the relative temperature of low and high ion components, the relative ion concentration of dust charge and the temperature. Numerical computation shows that for the chosen set of parameters, only compressive solitons exist and their amplitudes increase with increasing Mach number. An increase in the dust temperature results in the disappearance of the compressive soliton. It is the only small parameter regime where compressive as well rarefactive solitons coexist. The effect of the relative ion temperature on solitons is also investigated. In the small amplitude limit an increase in the dust temperature leads to a transition from compressive to rarefactive solitons.

A study of ion-acoustic solitons and double layers in a multispecies collisionless weakly relativistic plasma

The effect on the propagation of ion-acoustic solitons and double layers has been studied in collisionless weakly relativistic plasma consisting of two-electron temperature with isothermal electrons and finite ion temperature. The Korteweg de-Vries (KdV) equation is derived for ion-acoustic solitons propagating in a collisionless plasma. This equation is solved in a stationary frame to obtain the expression for soliton phase velocity, soliton width and peak soliton amplitude. It is observed that these quantities are significantly influenced by the relativistic effect, ion temperature, low-temperature electron density and ratio of cold to hot electron temperatures. Many features expected from hot ion theory and two species electron plasmas automatically emerge. The analysis is further extended to higher order nonlinearity and modified Korteweg de-Vries (mKdV) equation is derived. Even though compressive and rarefactive ion-acoustic solitons are obtained, only rarefactive ion-acoustic double layers are obtained in the present investigation.

Study of large amplitude solitons in multispecies plasma with non-Maxwellian electrons

In this investigation, authors study the propagation of ion-acoustic solitons in a plasma consisting of multispecies with different concentration of masses, charged states, and non-Maxwellian electrons. In the small amplitude approach the reductive perturbation method is used to derive the evolution equation such as Korteweg de-Vries (KdV). The present method, Sagdeev pseudopotential deals with the full nonlinearity of plasma equations. The potential so obtained is general in nature and valid for the large amplitude waves is characterized for solitons as a function of Mach number, temperature of different species, distribution of electrons, different concentration of species over a wide range of parameter space. In the small amplitude approach, we may also obtained KdV solitons. The compressive and rarefactive solitons are observed for the certain set of parameters.

Higher-Order Nonlinear Effects on Wave Structures in a Multispecies Plasma with Nonisothermal Electrons

In the present investigation, we have studied ion-acoustic solitary waves in a plasma consisting of warm positive and negative ions and nonisothermal electron distribution. We have used reductive perturbation theory (RPT) and derived a dispersion relation which supports only two ion-acoustic modes, viz. slow and fast. The expression for phase velocities of these modes is observed to be a function of parameters like nonisothermality, charge and mass ratio, and relative temperature of ions. A modified Korteweg-de Vries (KdV) equation with a (1+1/2) nonlinearity, also known as Schamel-mKdV model, is derived. RPT is further extended to include the contribution of higher-order terms. The results of numerical computation for such contributions are shown in the form of graphs in different parameter regimes for both, slow and fast ion-acoustic solitary waves having several interesting features. For the departure from the isothermally distributed electrons, a generalized KdV equation is derived and solved. It is observed that both rarefactive and compressive solitons exist for the isothermal case. However, nonisothermality supports only the compressive type of solitons in the given parameter regime.

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.

Ion-acoustic solitons in multispecies spatially inhomogeneous plasmas

Ion-acoustic solitons are investigated in the spatially inhomogeneous plasma having electrons-positrons and ions. The soliton characteristics are described by Korteweg-de Vries equation which has an additional term. The density and temperature of different species play an important role for the amplitude and width of the solitons. Numerical calculations show only the possibility of compressive solitons. Further, analytical results predict that the peak amplitude of soliton decreases with the decrease of density gradient. Soliton characteristics like peak amplitude and width are substantially different from those based on KdV theory for homogeneous plasmas

Localized nonlinear electrostatic structures in a multispecies space plasma

In this research paper, authors have studied ion-acoustic solitons in a warm multicomponent plasma consisting of warm positive and negative ions alongwith nonthermal electrons and an electron beam. Reductive perturbation method is used to derive KdV equation and dispersion relation, later a polynomial of six degree in phase velocity which corresponds to six ion-acoustic modes. Compressive as well as rarefactive solitons were found to exist corresponding to four linear modes, while other two wave modes support either compressive or rarefactive solitons in the given parameter regime. Study of KdV equation shows that nonthermality and electron beam parameters play crucial role in the characterization of solitons.

Dust‐acoustic Solitary Waves in Dusty Plasma with Non‐thermal Ions

In the present research paper, characteristics of dust‐acoustic solitary waves in dusty plasma are studied. The dust charge is treated as variable. KdV equation has been derived using reductive perturbation method. The effect of relative number density, relative ion temperature, non‐thermal parameter and variable charge has been numerically studied for possibility of both type of dust‐acoustic solitary waves.