Magnetized Electron Positron Ion Plasma Research Articles

Obliquely nonlinear solitary waves in magnetized electron–positron–ion plasma

Obliquely nonlinear solitary waves in magnetized electron–positron–ion plasma

Laser plasma interaction: plasma waves propagation and their instabilities in the inhomogeneous quantum magnetized electron–positron–ion plasma

Laser plasma interaction: plasma waves propagation and their instabilities in the inhomogeneous quantum magnetized electron–positron–ion plasma

Nonlinear excitations and dynamic features of dust ion-acoustic waves in a magnetized electron–positron–ion plasma

Abstract A wide class of nonlinear excitations and the dynamics of wave groups of finite amplitude ion-acoustic waves are investigated in multicomponent magnetized plasma system comprising warm ions, and superthermal electrons as well as positrons in presence of negatively charged impurities or dust particles. Employing the reductive perturbation technique (RPT), the Korteweg–de-Vries (KdV) equation, and extended KdV equation are derived. The presence of excess superthermal electrons as well as positrons and other plasma parameters are shown to influence the characteristics of both compressive and rarefactive solitons as well as double layers (DLs). Also, we extend our investigation by deriving the nonlinear Schrödinger equation from the extended KdV equation employing a suitable transformation to study the wave group dynamics for long waves. The analytical and numerical simulation results demonstrate that nonlinear wave predicts solitons, “table-top” solitons, DLs, bipolar structure, rogue waves, and breather structures. Moreover, implementing the concept of dynamical systems, phase portraits of nonlinear periodic, homoclinic trajectories, and supernonlinear periodic trajectories are presented through numerical simulation.

Ion-acoustic stable oscillations, solitary, periodic and shock waves in a quantum magnetized electron–positron–ion plasma

Abstract Nonlinear stable oscillations, solitary, periodic and shock waves in electron–positron–ion (EPI) quantum plasma in the presence of an external static magnetic field are reported. The Korteweg-de Vries-Burgers (KdVB) equation is derived by the reductive perturbation technique (RPT). The wave solution gives shock waves depending on various parameters as quantum diffraction parameter (β), electron and positron Fermi temperatures, and densities of the system species. Amplitude, polarity, speed, and width of wave solutions are remarkably modified by species densities, kinematic viscosity, and the Bohm potential. Existence of stable oscillation of ion-acoustic waves (IAWs) is shown by using the concept of phase plane analysis. Stability of wave solution is analysed by examining the Bohm potential effect. In the absence of dissipation, phase plane of the considered plasma system is analysed to discuss the existence of periodic wave solution. The results of this study could be helpful for comprehension of the wave features in dense quantum plasmas, like white dwarfs, laboratory plasma as interaction experiments of intense laser-solid matter and microelectronic devices.

Role of entropy in η i -mode driven nonlinear structures obtained by homotopy perturbation method in electron–positron–ion plasma

Abstract We present an analysis of the effect of entropy on ion temperature gradient η i -mode driven solitary and shock waves in electron–positron–ion plasma having density and temperature inhomogeneities. Linear and nonlinear analysis having solutions in form of solitons and shocks shows that entropy influence changes the drift mode instability. Different limiting cases when (i) temperature fluctuations due to E × B only (η i ≫ 2/3), (ii) in the absence of entropy and (iii) neglecting positron effect (β = 1) are discussed. The homotophy perturbation method (HPM) is applied on the derived Korteweg–de-Vries (KdV) and KdV–Burger equations under small time approximation. It is found that both results, those obtained analytically and by the HPM technique, strongly agree with each other. These investigations may be useful to study low frequency electrostatic modes in magnetized electron–positron–ion plasma. For illustration, the model has been applied to the nonlinear electrostatic excitations in interstellar medium and tokamak plasma.

Oblique propagation of nonlinear ion-acoustic cnoidal waves in magnetized electron–positron–ion plasmas with nonextensive electrons

Theoretical investigation of nonlinear electrostatic ion-acoustic cnoidal waves (IACWs) is presented in magnetized electron–positron–ion plasma with nonextensive electrons and Maxwellian positrons. Using reductive perturbation technique, Korteweg–de Vries equation is derived and its cnoidal wave solution is analyzed. For given plasma parameters, our model supports only positive potential (compressive) IACW structures. The effect of relevant plasma parameters (viz., nonextensive parameter q, positron concentration p, temperature ratio σ, obliqueness l 3) on the characteristics of IACWs is discussed in detail.

Dynamical behaviour of non‐linear quantum ion acoustic wave in weakly magnetized electron–positron–ion plasma

AbstractIn order to investigate the propagation characteristics of linear and non‐linear ion acoustic waves (IAWs) in electron–positron–ion quantum plasma in the presence of external weak magnetic field, we have used a quantum hydrodynamic model, and degenerate statistics for the electrons and positrons are taken into account. It is found that the linear dispersion relation of the IAW was modified by the externally applied magnetic field. By using the reductive perturbation technique, a gyration‐modified Korteweg‐de Vries equation is derived for finite amplitude non‐linear IAWs. Time‐dependent numerical simulation shows the formation of an oscillating tail in front of the ion acoustic solitons in the presence of a weak magnetic field. It is also seen that the amplitude and width of solitons and oscillating tails are affected by the relevant plasma parameters such as quantum diffraction, positron concentration, and magnetic field. We have performed our analysis by extending it to account for approximate soliton solution by asymptotic perturbation technique and non‐linear analysis via a dynamical system approach. The analytical results show the distortion of the shape of the localized soliton with time, and the non‐linear analysis confirms the generation of oscillating tails.

A transverse separate-spin-evolution streaming instability and new wave solutions in electron–positron–ion plasmas

This paper presents the analysis of dispersion equation for transverse waves in magnetized electron–positron–ion plasma in which electrons and positrons are counter streaming parallel to the magnetic field. The dispersion relation is derived through the separate spin evolution-quantum hydrodynamic (SSE–QHD) model. We find that the electron–positron dynamics taking account of the SSE for each species reveals the existence of new stable modes with no classical counterpart. Further, we report for the first time the existence of a new positron streaming driven transverse mode. The streaming effect enhances the instability in the electron–positron–ion plasma as compared to the electron–ion plasma. Moreover, it is found that both the positron imbalance and the streaming effects enhance the instability while the spin polarization suppresses it. The relevance of the present work for astrophysical e–p–i plasmas is also discussed.

Soliton-like solutions and chaotic motions for a forced and damped Zakharov–Kuznetsov equation in a magnetized electron–positron–ion plasma

A forced and damped Zakharov–Kuznetsov equation for a magnetized electron–positron–ion plasma affected by an external force is studied in this paper. Via the Hirota method, the soliton-like solutions are given. The soliton’s amplitude gets enhanced with the phase velocity${\it\lambda}$decreasing or ion-to-electron density ratio${\it\beta}$increasing. With the damped coefficient increasing, when the external force$g(t)$is periodic, the two solitons are always parallel during the propagation and background of the two solitons drops on the$x{-}y$plane, and amplitudes of the two solitons increase on the$x{-}t$and$y{-}t$planes, with$(x,y)$as the coordinates of the propagation plane and$t$as the time. When$g(t)$is exponentially decreasing, the two solitons merge into a single one and the background rises on the$x{-}y$plane, and amplitudes of the two solitons decrease on the$x{-}t$and$y{-}t$planes. Further, associated chaotic motions are obtained when$g(t)$is periodic. Using the phase projections and Poincaré sections, we find that the chaotic motions can be weakened with${\it\alpha}_{1}$, the amplitude of$g(t)$, decreasing. With${\it\alpha}_{2}$, the frequency of$g(t)$, decreasing, a three-dimensional attractor with stretching-and-folding structure is found, indicating that the weak chaos is transformed into the developed chaos. Chaotic motions can also be weakened with${\it\lambda}$, the phase velocity, decreasing, but strengthened with${\it\beta}$, the ion-to-electron density ratio, and${\it\alpha}_{2}$decreasing.

Polarization effect on the Raman backscattering of an electromagnetic wave propagating through an electron–positron–ion magnetoplasma

The present study is devoted to the investigation of stimulated Raman backscattering of an intense, circularly polarized electromagnetic wave in magnetized electron–positron–ion plasma. The nonlinear dispersion relation as well as the growth rate of instability is achieved. The effects of external magnetic field, fraction of electron–positron pairs, pump frequency and also the kind of polarization on the growth rate is studied. It is shown that an admixture of e–p pairs to the ion–electron plasma modifies the behavior of plasma with respect to the external magnetic field.

Head-on collision of electron acoustic solitary waves in dense magnetized electron–positron–ion plasma

In this paper, we study the head-on collision between two electron acoustic solitary waves (EASWs) in magnetized quantum electron–positron–ion plasma. Using the extended Poincaré–Lighthill–Kuo perturbation method, we obtain the Korteweg–de Vries equations, the phase shifts and the trajectories after the head-on collision of the two EASWs. It is found that the phase shifts are significantly affected by the values of the quantum parameter H, the ion to electron number density ratio δ, the electron cyclotron to electron plasma frequency ratio α and the obliqueness θ (propagation angle).

Relaxation of a magnetized electron–positron–ion plasma with flows

It is shown that possible relaxed magnetic field configurations of a magnetized electron–positron–ion (e–p–i) plasma with flows can be described by a triple curl Beltrami (TCB) equation, which is equivalent to the superposition of three different Beltrami fields. The TCB equation admits three relaxed structures when the linear and nonlinear inertial forces of all three plasma species involved are taken into account. One of the structures represents the system size while the remaining two could be of the order of electron skin depth.

Generation of sheared flows by drift waves in a strongly magnetized electron–positron–ion plasma

AbstractIt is shown that sheared/zonal flows (ZFs) can be nonlinearly excited by incoherent drift waves (DWs) in a strongly magnetized non-uniform plasma composed of electrons, positrons and ions. The dynamics of incoherent DWs in the presence of ZFs is governed by a wave-kinetic equation. The governing equation for ZFs in the presence of nonlinear forces (associated with nonlinear ion polarization and nonlinear ion-diamagnetic drifts) of the DWs is deduced by combining the Poisson equation, as well as the e-p-i continuity equations, together with appropriate plasma particle velocities in the DW and the ZF fields. Standard techniques are used to derive a nonlinear dispersion relation, which depicts two classes of the modulational instability of the DWs against the ZFs. Non-thermal ZFs can reduce the turbulent cross-field particle transport in non-uniform, strongly magnetized e-p-i plasmas.

Ion acceleration by the space charge electric force arising from the radiation pressure in a magnetized electron–positron plasma

It is shown that ions can be accelerated by the space charge electric force arising from the separation of electrons and positrons due to the ponderomotive force of the magnetic field-aligned circularly polarized electromagnetic (CPEM) wave in a magnetized electron–positron–ion plasma. The ion acceleration critically depends on the external magnetic field strength. The result is useful in understanding differential ion acceleration in magnetized electron–positron–ion plasmas, such as those in magnetars and in some laboratory experiments that aim to mimic astrophysical environments.

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.

Generation of wakefields by electromagnetic waves in a magnetized electron–positron–ion plasma

The generation of electrostatic wakefields by an ordinary mode radiation and a magnetic field-aligned circularly polarized electromagnetic (CPEM) wave in a magnetized electron–positron–ion (e–p–i) plasma is considered. It is found that the presence of the ions is essential for the generation of upper-hybrid wakefields by the ordinary mode radiation, while the magnetic field-aligned electron plasma wakefields are created by the ponderomotive force of CPEM only if either the ions or the external magnetic field is present in an e–p–i magnetoplasma. The electromagnetic wave generated wakefields can trap both the electrons and the positrons and accelerate them to very high energies.

Acceleration of ions by the radiation pressure in a magnetized electron–positron–ion plasma

It is shown that the ponderomotive force of magnetic-field aligned circularly polarized electromagnetic waves can create space charge electric fields in a magnetized electron positron ion plasma. The space charge electric fields can, in turn, accelerate ions. Possible applications to the origin of energetic ions in laboratory plasmas and astrophysical settings are discussed.

Positron acceleration to ultrarelativistic energies by a shock wave in a magnetized electron–positron–ion plasma

Positron acceleration in oblique shock waves is studied with relativistic, electromagnetic, particle simulations with full particle dynamics. In the simulations, some positrons have been accelerated to energies γ∼600, where γ is the Lorentz factor. The electric field parallel to the magnetic field plays an essential role in the acceleration; it prevents some positrons from passing through the shock wave. For certain shock propagation velocities and angles, these positrons stay around the shock front for long periods of time, moving roughly parallel to the external magnetic field, and gain great energies. These properties are in good agreement with a proposed acceleration model.

Vortices in a Strongly Magnetized Electron–Positron–Ion Plasma

A theoretical investigation has been presented for the linear and nonlinear properties of obliquely propagating coupled low-frequency electrostatic drift and ion-acoustic (ED-IA) waves in a strongly magnetized nonuniform electron–positron–ion plasma in the presence of sheared ion flow. A result from our linear analysis is that the ED-IA waves can be unstable due to the ion sheared flow. In addition, it is shown that the nonlinear equations governing the dynamics of weakly interacting ED-IA waves admit vortex solutions of two different classes viz. a vortex chain and a double vortex.

On the existence of small amplitude double layers in an electron–positron–ion plasma

A theoretical model is presented to investigate the double layers, associated with the kinetic Alfvén waves, in a magnetized electron–positron–ion plasma with a small but finite value of β, and small-amplitude double layer solutions are obtained. The existence of small-amplitude double layers requires that the density of ions is appreciably larger than that of positrons at equilibrium. The properties of the double layers are determined by the ratio between the number densities of positrons and ions at equilibrium, the direction cosines defining the moving frame, as well as the electron to positron temperature ratio.