Electrostatic electron acoustic solitons in electron-positron-ion plasma with superthermal electrons and positrons

Properties of fully nonlinear electron-acoustic solitary waves in an unmagnetized and collisionless electron-positron-ion plasma containing cold dynamical electrons, superthermal electrons and positrons obeying Cairns’ distribution have been analyzed in the stationary background of massive positive ions. A linear dispersion relation has been derived, from which it is found that even in the absence of superthermal electrons, the superthermal positron component can provide the restoring force to the cold inertial electrons to excite electron-acoustic waves. Moreover, superthermal electron and positron populations seem to enhance the electron acoustic wave phase speed. For nonlinear analysis, Korteweg-de Vries equation is obtained using the reductive perturbation technique. It is found that in the presence of positron both hump and dip type solitons appear to excite. The present work may be employed to explore and to understand the formation of electron acoustic soliton structures in the space and laboratory plasmas with nonthermal electrons and positrons.     

Rogue waves for Kadomstev-Petviashvili equation in electron-positron-ion plasma

The nonlinear ion-acoustic waves in plasma having excess super-thermal electrons and positrons have been investigated. Reductive perturbation method is used to obtain a Kadomstev-Petviashvili equation describing the system. The dynamics of the modulationally unstable wave packets described by the Kadomstev-Petviashvili equation gives rise to the formation of rogue excitation that is described by a nonlinear Schrödinger equation. The dependence of rogue waves profiles on the system parameters investigated numerically. The result of the present investigation may be applicable to some plasma environments, such as galactic clusters, interstellar medium.     

Arbitrary amplitude ion-acoustic solitary waves in superthermal electron-positron-ion magnetoplasma

Arbitrary amplitude ion-acoustic solitary waves propagating in a magnetized plasma composed of positive ions, superthermal electrons and positrons are investigated. For this purpose, the ions are represented by the hydrodynamical fluid equations while the non-Maxwellian electrons and positrons densities are assumed to follow kappa (κ) distribution. The basic equations are reduced to a pseudoenergy-balance equation. Existence conditions for large amplitude solitary waves are presented. The analytical and numerical analysis of the latter show that the ion-acoustic solitary wave can propagate only in the subsonic region in our plasma system and it is significantly influenced by the plasma parameters. The present analysis could be helpful for understanding the nonlinear ion-acoustic solitary waves propagating in interstellar medium and pulsar wind, which contain an excess of superthermal particles.     

Cylindrical and spherical ion acoustic solitary waves in electron-positron-ion plasmas with superthermal electrons

Propagation of cylindrical and spherical ion acoustic solitary waves in plasmas consisting of cold ions, superthermal electrons and thermal positrons are investigated. It is shown that cylindrical/spherical Korteweg-de-Vries equation governs the dynamics of ion-acoustic solitons. The effects of nonplanar geometry and also superthermal electrons on the characteristics of solitary wave structures are studied using numerical simulations. Obtained results are compared with the results of the other published papers and errors in the results of some papers are pointed.     

Effects of double temperature superthermal electrons on dust-ion-acoustic shock waves in electron-positron-ion dusty plasmas

A rigorous theoretical investigation on the characteristics of dust-ion-acoustic (DIA) shock waves in an unmagnetized multi component electron-positron-ion dusty plasma (consisting of inertial ions, electrons of two distinct temperatures referred to as low and high temperature superthermal electrons where superthermality is introduced via the κ-type of nonthermal distribution, Boltzmann distributed positrons, and negatively charged immobile dust grains) has been made both theoretically and analytically. The hydrodynamic equation for inertial ions has been used to derive the Burgers equation. The influence of superthermal electrons, Maxwellian positrons and ion kinematic viscosity, which are found in this investigation, significantly modify the basic features of DIA shock waves, are briefly discussed. The present investigation can be very effective for studying and understanding the basic characteristics of shock wave propagation through different astrophysical situations where distinct temperature superthermal electrons dominate the wave dynamics.     

Magnetosonic cylindrical soliton in electron-positron-ion plasma

Solutions in the form of cylindrical magnetosonic solitons of compression and rarefaction were obtained within the scope of the three-species electromagnetic gas-dynamic model of an electron-positron-ion plasma. These solutions can describe formation of cylindrical structures in accretion disks and jets in the vicinity of compact astrophysical objects.     

Ion-acoustic waves in non-Maxwellian magnetospheric electron-positron-ion plasma

Using Boltzmann-Vlasov kinetic model for nonthermal distributed electron-positron-ion plasma of our Earth’s magnetosphere and the solar wind streaming plasma can drive ion-acoustic waves unstable. It is found that the growth rate increases with the decrease of spectral index and increases with the streaming velocity of the solar wind. The numerical results are also presented by choosing some suitable parameters of magnetospheric plasma.     

Ion acoustic soliton in relativistic degenerate electron-positron-ion plasma

Large amplitude ion-acoustic (IA) soliton in a fully relativistic plasma consisting of relativistic cold ions and relativistic degenerate electrons and positrons are investigated. It is shown that the features of IA soliton are strengthened increasingly with relativistic effects. The relativistic degeneracy of electrons and positrons acts in opposite way on the properties of the IA soliton. The latter becomes more flatten in the first case and narrower in the second one.     

Obliquely propagating ion-acoustic double layers in magnetized electron-positron-ion plasma

Ion–acoustic double layers has been studied in magnetized electron-positron-ion plasma. The modified Korteweg-de Vries (m-KdV) is derived using reductive perturbation method. It is found that for the selected set of parameters, the system supports rarefactive (compressive) double layers depending upon the values of cold electron concentration (μ). It is also found that the magnetization affects only the width of the double layer. For a given set of parameter values, as we increases the magnetization, the width of the double layer increases and an increases in the obliqueness θ, where θ is the angle between wave vector and magnetic field, the width of the double layer also increases. The angle of obliqueness θ does not affects the amplitude of the double layer. It is also investigated that for the given set of parameter values, on increasing the positron concentration the amplitude of the rarefactive (compressive) double layer decreases (increases), and the width of the rarefactive (compressive) double layer increases (decreases). The effect of the temperature ratios of ions and positron on the amplitude and width of the double layers are discussed.     

Electromagnetic wave instability in a relativistic electron-positron-ion plasma

By employing the anisotropic plasma distribution function, the stability of circularly polarized electromagnetic (EM) waves is studied in a relativistically hot electron-positron-ion (e-p-i) plasma, investigating two specific scenarios. First, linear dispersion relations associated with the transverse EM waves are analyzed in different possible frequency regimes. The expression of the aperiodic hydrodynamic instability is obtained and numerically the transverse EM modes are shown to grow exponentially. Secondly, we have found that the transverse electromagnetic wave interact with a collisionless anisotropic e-p-i plasma and damp through the nonlinear Landau damping phenomena. Taking the effects of the latter into consideration, a kinetic nonlinear Schrödinger equation is derived with local and nonlocal nonlinearities, computing the damping rates. The present work should be helpful to understand the linear and nonlinear properties of the intense EM waves in hot relativistically astrophysical plasmas, e.g., pulsars, black holes, neutron stars, etc.     

Ion acoustic solitary waves in magnetized nonextensive electron-positron-ion plasma

The combined effects of the obliqueness and nonextensive electrons are incorporated in the study of ion-acoustic (IA) solitary waves in a magnetized electron-positron-ion (e-p-i) plasma. The nonlinear Korteweg-de Vries (KdV) equation is derived by using the reductive perturbation method. The plasma parameters such as, the degree of nonextensivity, obliqueness, positron concentration and temperature ratio are found to significantly affect the solitary waves characteristics. Also, a critical value of nonextensivity is found for which solitary structures transit from positive to negative potential. Our finding contributes to the physics of the nonlinear electrostatic excitation in astrophysical and cosmological scenarios like magnetosphere, polar cups region of pulsars, neutron stars and white dwarfs, etc., where magnetized e-p-i plasma can exist.     

Electron-acoustic solitary structures in two-electron-temperature plasma with superthermal electrons

The propagation of nonlinear electron-acoustic waves (EAWs) in an unmagnetized collisionless plasma system consisting of a cold electron fluid, superthermal hot electrons and stationary ions is investigated. A reductive perturbation method is employed to obtain a modified Korteweg–de Vries (mKdV) equation for the first-order potential. The small amplitude electron-acoustic solitary wave, e.g., soliton and double layer (DL) solutions are presented, and the effects of superthermal electrons on the nature of the solitons are also discussed. But the results shows that the weak stationary EA DLs cannot be supported by the present model.     

Nonlinear propagation of ion-acoustic waves in an electron-positron-ion plasma

A theoretical investigation has been made of electrostatic solitary structures in an electron-positron-ion (e-p-i) plasma, taking nonextensive electrons and nonextensive positrons. By employing the reductive perturbation method, the basic characteristics of ion-acoustic (IA) solitary waves (SWs) in a three-component e-p-i plasma (consisting of negatively charged nonextensive electrons, positively charged nonextensive positrons, and ions) have been addressed. The Korteweg-de Vries (K-dV), modified K-dV (mK-dV), and Gardner equations are derived and their numerical solutions are obtained. It has been shown that the combined effects of electron nonextensivity, positron nonextensivity, and ions significantly modify the behavior of these electrostatic solitary structures that have been found to exist with positive and negative potential in this plasma model. The present analysis may be useful to understand and demonstrate the dynamical properties of IA SWs in different astrophysical and cosmological scenarios (viz. stellar polytropes, hadronic matter and quark-gluon plasma, protoneutron stars, dark-matter halos, etc.).     

Ion acoustic solitary waves in bi-ion plasma with superthermal electrons

Weak ion-acoustic solitary waves (IASWs) in unmagnetized plasmas having two-fluid ions and kappa-distributed electrons are considered. The effects of electron suprathermality, warm ion temperature and polarity on the nonlinear properties of these IASWs are analyzed. It is found that our present plasma model may support compressive as well as rarefactive solitary structures.     

Modulational instability of ion-acoustic soliton in electron-positron-ion plasma with dust particulates

Theoretical investigation has been made to study the envelope excitations of ion-acoustic solitons (IAS) in plasma composed of electrons, positrons, ions and dust particles. A nonlinear Schrödinger equation which describes the modulational instability of the IAS is derived by using the multiple scale method. The dispersive and nonlinear coefficients are obtained which depend upon the temperature of the ions, concentration of the positrons, electrons and dust particles. The modulationally stable and unstable regions are studied numerically for a wide range of parameters. It is found that these parameters play significant role in the formation of bright and dark envelope solitons in this plasma system.     

Dust ion acoustic travelling waves in the framework of a modified Kadomtsev-Petviashvili equation in a magnetized dusty plasma with superthermal electrons

For the critical values of the parameters q and V, the work (Samanta et al. in Phys. Plasma 20:022111, 2013b) is unable to describe the nonlinear wave features in magnetized dusty plasma with superthermal electrons. To describe the nonlinear wave features for critical values of the parameters q and V, we extend the work (Samanta et al. in Phys. Plasma 20:022111, 2013b). To extend the work, we derive the modified Kadomtsev-Petviashvili (MKP) equation for dust ion acoustic waves in a magnetized dusty plasma with q-nonextensive velocity distributed electrons by considering higher order coefficients of ?. By applying the bifurcation theory of planar dynamical systems to this MKP equation, the existence of solitary wave solutions of both types rarefactive and compressive, periodic travelling wave solutions and kink and anti-kink wave solutions is proved. Three exact solutions of these above waves are determined. The present study could be helpful for understanding the nonlinear travelling waves propagating in mercury, solar wind, Saturn and in magnetosphere of the Earth.     

Head-on collision of magnetoacoustic solitary waves in magnetized quantum electron-positron-ion plasma

This article presents the first study of the head-on collision between two magnetoacoustic solitary waves (MASWs) in magnetized quantum plasma consisting of electrons, positrons, and ions, using the extended Poincaré-Lighthill-Kou (PLK) method. The effects of the magnetic field intensity, the positron to ion number density ratio, the quantum parameter, the Fermi temperature ratio, and plasma number density on the solitary wave collisions are investigated. It is shown that these factors significantly modify the phase shift.     

Soliton and shocks in pair ion plasma in presence of superthermal electron

Solitons and shocks are addressed in a pair ion plasma in the presence of a kappa distribution. The dissipation is taken care of through the kinematic viscosity of both positive and negative ions in the plasma. The Kadomtsev–Petviashvili–Burger (KPB) equation is derived using the small amplitude expansion method. The Abel equation is obtained from the KPB equation and a solution is obtained by using the factorization method. The effect of the parameters κ and β (temperature ratio of ion species) is observed. Analytically we can find both solitons and shocks. The change of profile from soliton to shocks is shown in the figures. This study may be of wide relevance for the study of the formation of shocks and solitons in laboratory-produced pair ion plasmas.     

Obliquely propagating ion-acoustic waves in a magnetized electron-positron-ion plasma with trapped electrons

A theoretical investigation is carried out for understanding the basic features of oblique propagation of linear and nonlinear ion-acoustic waves subjected to an external magnetic field in an electron-positron-ion plasma which consists of a cold magnetized ion fluid, Boltzmann distributed positron, and electrons obeying a trapped distribution. In the linear regime, two dispersion curves are obtained. It is shown that the positron concentration causes the both modes to propagate with smaller phase velocities. Then, owing to the presence of resonant electrons, the modified Korteweg-de Vries equation describing the nonlinear dynamics of small but finite amplitude ion-acoustic waves is derived. It is found that the effects of external magnetic field (obliqueness), trapped electrons, positron concentration and temperature ratio significantly modify the basic features of solitary waves.