Nonlinear ion acoustic excitations in relativistic degenerate, astrophysical electron–positron–ion plasmas

AbstractThe dynamics and propagation of ion acoustic (IA) waves are considered in an unmagnetized collisionless plasma, whose constituents are the relativistically degenerate electrons and positrons as well as the inertial cold ions. At a first step, a linear dispersion relation for IA waves is derived and analysed numerically. For nonlinear analysis, the reductive perturbation technique is used to derive a Korteweg–deVries equation, which admits a localized wave solution in the presence of relativistic degenerate electrons and positrons. It is shown that only compressive IA solitary waves can propagate, whose amplitude, width and phase velocity are significantly modified due to the positron concentration. The latter also strongly influences all the relativistic plasma parameters. Our present analysis is aimed to understand collective interactions in dense astrophysical objects, e.g. white dwarfs, where the lighter species electrons and positrons are taken as relativistically degenerate.

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Overtaking Collisions of Ion Acoustic N-Shocks in a Collisionless Plasma with Pair-Ion and (α,q) Distribution Function for Electrons

Applied Sciences ◽

10.3390/app10176115 ◽

2020 ◽

Vol 10 (17) ◽

pp. 6115 ◽

Cited By ~ 1

Author(s):

Md. Golam Hafez ◽

Parvin Akter ◽

Samsul Ariffin Abdul Karim

Keyword(s):

Shock Wave ◽

Perturbation Technique ◽

Dynamical Behavior ◽

Collisionless Plasma ◽

Negative Ions ◽

Experimental Investigations ◽

Plasma Parameters ◽

Ion Acoustic ◽

Shock Wave Solution ◽

Density Ratios

In this work, the effects of plasma parameters on overtaking collisions of ion acoustic multi-shocks are studied in an unmagnetized collisionless plasma with positive and negative ions, and (α,q)-distributed electrons. To investigate such phenomena, the reductive perturbation technique is implemented to derive the Burgers equation. The N-shock wave solution is determined for this equation by directly implementing the exponential function. The result reveals that both the amplitudes and thicknesses of overtaking collisions of N-shock wave compressive and rarefactive electrostatic potential are significantly modified with the influences of viscosity coefficients of positive and negative ions. In addition, the density ratios also play an essential role to the formation of overtaking collisions of N-shocks. It is observed from all theoretical and parametric investigations that the outcomes may be very useful in understanding the dynamical behavior of overtaking collisions of multi-shocks in various environments, especially the D- and F-regions of the Earth’s ionosphere and the future experimental investigations in Q-machine laboratory plasmas.

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Stimulated Brillouin backscattering of a ring-rippled laser beam in collisionless plasma

Laser and Particle Beams ◽

10.1017/s0263034615000555 ◽

2015 ◽

Vol 33 (3) ◽

pp. 499-509 ◽

Cited By ~ 5

Author(s):

Gunjan Purohit ◽

Priyanka Rawat

Keyword(s):

Laser Beam ◽

Narrow Range ◽

Brillouin Scattering ◽

Collisionless Plasma ◽

Plasma Parameters ◽

Ion Acoustic Wave ◽

Coupled Equations ◽

Ion Acoustic ◽

Paraxial Ray ◽

Stimulated Brillouin

AbstractThe effect of the propagation of a ring-rippled laser beam in the presence of relativistic and ponderomotive non-linearities on the excitation of ion-acoustic wave (IAW) and resulting stimulated Brillouin backscattering in collisionless plasma at relativistic powers is studied. To understand the nature of propagation of the ring ripple-like instability, a paraxial-ray approach has been invoked in which all the relevant parameters correspond to a narrow range around the irradiance maximum of the ring ripple. Modified coupled equations for growth of ring ripple in the plasma, generations of IAW and back-stimulated Brillouin scattering (SBS) are derived from fluid equations. These coupled equations are solved analytically and numerically to study the intensity of ring-rippled laser beam and excited IAW as well as back reflectivity of SBS in the plasma for various established laser and plasma parameters. It is found that the back reflectivity of SBS is enhanced due to the strong coupling between ring-rippled laser beam and the excited IAW. The results also show that the back reflectivity of SBS reduce for higher intensity of the laser beam.

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Longitudinal waves in a perpendicular collisionless plasma shock: II. Vlasov ions

Journal of Plasma Physics ◽

10.1017/s0022377800005407 ◽

1970 ◽

Vol 4 (4) ◽

pp. 753-760 ◽

Cited By ~ 63

Author(s):

S. Peter Gary

Keyword(s):

Collisionless Plasma ◽

Maximum Growth ◽

Zero Magnetic Field ◽

Linear Dispersion ◽

Electrostatic Waves ◽

Longitudinal Waves ◽

Acoustic Instability ◽

Ion Acoustic ◽

Plasma Shock ◽

Vlasov Plasma

This paper presents an analysis of the linear dispersion relation for electrostatic waves in a Vlasov plasma of unmagnetized, Maxwellian ions and magnetized, Maxwellian electrons. The electrons undergo E × B and ∇B drifts, and the electron β is small. For propagation in the perpendicular direction, maximum growth rates can be substantially larger than those of the zero magnetic field ion acoustic instability. For propagation outside a few degrees from the perpendicular the dispersion characteristics are essentially those of the ion acoustic instability.

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Ion acoustic quasi-soliton in an electron-positron-ion plasma with superthermal electrons and positrons

Open Physics ◽

10.1515/phys-2018-0073 ◽

2018 ◽

Vol 16 (1) ◽

pp. 563-567 ◽

Cited By ~ 2

Author(s):

Jianyong Wang ◽

Ying Zeng ◽

Zufeng Liang ◽

Yani Xu ◽

Yuanxiang Zhang

Keyword(s):

Acoustic Waves ◽

Vries Equation ◽

Reductive Perturbation Method ◽

Superthermal Electrons ◽

Ion Plasma ◽

Electron Positron ◽

Electrons And Positrons ◽

Ion Acoustic ◽

De Vries ◽

Superthermal Electrons And Positrons

Abstract In this work, we are concerned with the ion acoustic quasi-soliton in an electron-positron-ion plasma with superthermal electrons and positrons. By using the reductive perturbation method, the Korteweg-de Vries equation is derived from the governing equations of ion acoustic waves. An interesting soliton-cnoidal wave solution of the Korteweg-de Vries equation and its quasi-soliton behaviour are presented. The influence of electron superthermality, positron superthermality and positron concentration ratio on characteristics of the quasi-soliton is confirmed to be significant.

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Nonlinear electrostatic solitary waves in electron–positron plasmas

Journal of Plasma Physics ◽

10.1017/s0022377816000076 ◽

2016 ◽

Vol 82 (1) ◽

Cited By ~ 4

Author(s):

I. J. Lazarus ◽

R. Bharuthram ◽

S. Moolla ◽

S. V. Singh ◽

G. S. Lakhina

Keyword(s):

Solitary Waves ◽

Laboratory Experiments ◽

Nonlinear Propagation ◽

Plasma Parameters ◽

Electron Positron ◽

Electrons And Positrons ◽

Fluid Theory ◽

Temperature Electron ◽

Propagation Of Waves ◽

Two Temperature

The generation of nonlinear electrostatic solitary waves (ESWs) is explored in a magnetized four component two-temperature electron–positron plasma. Fluid theory is used to derive a set of nonlinear equations for the ESWs, which propagate obliquely to an external magnetic field. The electric field structures are examined for various plasma parameters and are shown to yield sinusoidal, sawtooth and bipolar waveforms. It is found that an increase in the densities of the electrons and positrons strengthen the nonlinearity while the periodicity and nonlinearity of the wave increases as the cool-to-hot temperature ratio increases. Our results could be useful in understanding nonlinear propagation of waves in astrophysical environments and related laboratory experiments.

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Dust Ion-Acoustic Shock Waves in a Multicomponent Magnetorotating Plasma

Zeitschrift für Naturforschung A ◽

10.1515/zna-2017-0397 ◽

2018 ◽

Vol 73 (3) ◽

pp. 215-223 ◽

Cited By ~ 4

Author(s):

Barjinder Kaur ◽

N.S. Saini

Keyword(s):

Shock Waves ◽

Kinematic Viscosity ◽

Perturbation Technique ◽

Dusty Plasmas ◽

Rotational Frequency ◽

Physical Parameters ◽

Charged Dust ◽

Nonlinear Properties ◽

Electrons And Positrons ◽

Ion Acoustic

AbstractThe nonlinear properties of dust ion-acoustic (DIA) shock waves in a magnetorotating plasma consisting of inertial ions, nonextensive electrons and positrons, and immobile negatively charged dust are examined. The effects of dust charge fluctuations are not included in the present investigation, but the ion kinematic viscosity (collisions) is a source of dissipation, leading to the formation of stable shock structures. The Zakharov–Kuznetsov–Burgers (ZKB) equation is derived using the reductive perturbation technique, and from its solution the effects of different physical parameters, i.e. nonextensivity of electrons and positrons, kinematic viscosity, rotational frequency, and positron and dust concentrations, on the characteristics of shock waves are examined. It is observed that physical parameters play a very crucial role in the formation of DIA shocks. This study could be useful in understanding the electrostatic excitations in dusty plasmas in space (e.g. interstellar medium).

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Effect of self-focused rippled laser beam on the excitation of ion acoustic wave in relativistic ponderomotive regime

Laser and Particle Beams ◽

10.1017/s0263034614000512 ◽

2014 ◽

Vol 32 (4) ◽

pp. 557-568 ◽

Cited By ~ 3

Author(s):

Rakhi Gauniyal ◽

Prashant Chauhan ◽

Priyanka Rawat ◽

Gunjan Purohit

Keyword(s):

Acoustic Wave ◽

Laser Beam ◽

Collisionless Plasma ◽

Plasma Parameters ◽

Power Flux ◽

Ion Acoustic Wave ◽

Coupled Equations ◽

Increase With Increase ◽

Ion Acoustic ◽

Paraxial Ray

AbstractThis paper presents an investigation of self-focusing of intense Gaussian rippled laser beam in collisionless plasma by including the nonlinearity associated with the relativistic mass and the ponderomotive force and its effects on the excitation of ion acoustic wave. The growth of ripple, riding on an intense Gaussian laser beam in plasma and its coupling with ion acoustic wave has also been studied. Modified coupled equations for main laser beam, growth of laser ripple in plasma, rippled laser beam, beam width, and density perturbation associated with ion acoustic wave are derived using Wentzel-Kramers-Brillouin and paraxial ray approximation. These coupled equations are solved analytically and numerically to study the laser intensity in plasma and the variation of amplitude of the ion acoustic wave for various established laser and plasma parameters. From numerical computation, it is observed that both nonlinearities significantly affected the dynamics of the growth of laser ripple in plasma, propagation of rippled laser beam as well as ion acoustic wave in plasma at high laser power flux. The growth of laser ripple increase with increase in the intensity of laser beam and due to the contribution of growth rate, intensity profile of rippled laser beam and ion acoustic wave modified accordingly.

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