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

2020 ◽  
Vol 10 (17) ◽  
pp. 6115 ◽  
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.

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

2013 ◽  
Vol 79 (5) ◽  
pp. 817-823 ◽  
Author(s):  
ATA-UR RAHMAN ◽  
S. ALI ◽  
A. MUSHTAQ ◽  
A. QAMAR
Keyword(s):  
Perturbation Technique ◽  
Collisionless Plasma ◽  
Plasma Parameters ◽  
Linear Dispersion ◽  
Electron Positron ◽  
Electrons And Positrons ◽  
Ion Acoustic ◽  
Astrophysical Objects ◽  
Collective Interactions ◽  
Acoustic Excitations

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.

Ion-acoustic envelope excitations in multispecies plasma with non-thermally distributed electrons

2012 ◽  
Vol 78 (3) ◽  
pp. 265-278 ◽  
Author(s):  
PARVEEN BALA ◽  
TARSEM SINGH GILL ◽  
HARVINDER KAUR
Keyword(s):  
Acoustic Waves ◽  
Modulational Instability ◽  
Perturbation Technique ◽  
Negative Ions ◽  
Finite Amplitude ◽  
Acoustic Mode ◽  
Relative Temperature ◽  
Ion Acoustic ◽  
Unmagnetized Plasma ◽  
Density Ratios

AbstractBy using the standard reductive perturbation technique, a nonlinear Schrödinger equation is derived to study the stability of finite amplitude ion-acoustic waves in an unmagnetized plasma consisting of warm positive and negative ions and non-thermal electrons. The effect of relative temperature of positive and negative ions, their charge and mass ratios, density ratios and non-thermally distributed electrons on modulational instability of fast and slow ion-acoustic mode is investigated. It is found that these parameters significantly change the domain of modulation instability. Both, envelope and dark solitons appear in different regions of parameter space.

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

2015 ◽  
Vol 33 (3) ◽  
pp. 499-509 ◽  
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.

Space Potential and Ion Energies in a Low Pressure Discharge Containing at least Two Negative Species

1988 ◽  
Vol 117 ◽  
Author(s):  
S G Ingram ◽  
N St J Braithwaite
Keyword(s):  
Energy Distribution ◽  
Collisionless Plasma ◽  
Negative Ions ◽  
Potential Drop ◽  
Low Pressure ◽  
Type Model ◽  
Plasma Parameters ◽  
Ion Energy ◽  
Ion Energy Distribution ◽  
Positive Ion

AbstractA Tonks-Langmuir type model for a one-dimensional low pressure (collisionless) plasma containing at least two species of Maxwellian negative charge carriers is examined. The solutions of this model yield the positive ion energy distribution at the sheath edge without needing to specify the ionization process. This distribution has a width consistent with the potential drop across the plasma, and is shown to satisfy the generalised Bohm criterion for sheath formation. However by assuming a form for the ionization rate in the plasma, the potential profile across the discharge has been calculated. It has been found that for a range of plasma parameters the solution for the potential at which quasineutrality fails becomes triple valued; the physical solution in this regime is identified.Many plasmas used for materials processing contain negative ions. It is important to understand how these ions influence the positive ion energy distribution at the substrate where the processing occurs.This work is also of relevance to the behaviour of Langmuir probes in electronegative plasmas.

scholarly journals Effect of Space Fractional Parameter on Nonlinear Ion Acoustic Shock Wave Excitation in an Unmagnetized Relativistic Plasma

2022 ◽  
Vol 9 ◽  
Author(s):  
M.F. Uddin ◽  
M.G. Hafez ◽  
Inho Hwang ◽  
Choonkil Park
Keyword(s):  
Shock Wave ◽  
Fluid Model ◽  
Reductive Perturbation Method ◽  
Relativistic Plasma ◽  
Polar Regions ◽  
Viscous Effects ◽  
Plasma Parameters ◽  
Ion Acoustic ◽  
Acoustic Shock Wave ◽  
Space Environments

In this work, the model equation with space fractional-order (FO) is used to investigate the nonlinear ion acoustic shock wave excitations (NIASWEs) in an unmagnetized collisionless weakly relativistic plasma having inertial relativistic ions fluid with viscous effects, inertial-less non-thermal electrons and inertial-less Boltzmann positrons. To do it, the Korteweg-de Vries Burgers equation (KdVBE) is derived from the considered fluid model equations by implementing the standard reductive perturbation method. Accordingly, such equation is converted to space fractional KdVBE via Agrawal’s variational principle with the help of the beta fractional derivative and its properties. The exact analytical solutions of KdVBE with space FO are determined via the modified Kudryashov method. The influence of space fractional and other related plasma parameters on NIASWEs are investigated. The outcomes would be useful to understand the nature of shocks with the presence of non-local or local space in many astrophysical and space environments (especially in the relativistic wind of pulsar magnetosphere, polar regions of neutron stars, etc.) and further laboratory verification.

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

2014 ◽  
Vol 32 (4) ◽  
pp. 557-568 ◽  
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.

Nonlinear propagation of dust-ion-acoustic solitary waves in an unmagnetized dusty plasma with trapped particle distribution

2015 ◽  
Vol 30 (40) ◽  
pp. 1550216 ◽  
Author(s):  
O. Rahman
Keyword(s):  
Dusty Plasma ◽  
Solitary Waves ◽  
Perturbation Technique ◽  
Negative Ions ◽  
Mkdv Equation ◽  
Finite Amplitude ◽  
Negative Ion ◽  
Nonlinear Propagation ◽  
Ion Distribution ◽  
Ion Acoustic

The nonlinear propagation of dust-ion-acoustic (DIA) solitary waves (SWs) in an unmagnetized four-component dusty plasma containing electrons and negative ions obeying vortex-like (trapped) velocity distribution, cold mobile positive ions and arbitrarily charged stationary dust has been theoretically investigated. The properties of small but finite amplitude DIASWs are studied by employing the reductive perturbation technique. It has been found that owing to the departure from the Maxwellian electron and Maxwellian negative ion distribution to a vortex-like one, the dynamics of such DIASWs is governed by a modified Korteweg–de Vries (mKdV) equation which admits SW solution under certain conditions. The basic properties (speed, amplitude, width, etc.) of such DIASWs are found to be significantly modified by the presence of trapped electron and trapped negative ions. The implications of our results to space and laboratory dusty electronegative plasmas (DENPs) are briefly discussed.

Comment on Ion Acoustic Shocks in a Collisionless Plasma with Negative Ions

1999 ◽  
Vol T82 (1) ◽  
pp. 104
Author(s):  
Yoshiharu Nakamura ◽  
Padma K. Shukla
Keyword(s):  
Collisionless Plasma ◽  
Negative Ions ◽  
Ion Acoustic

scholarly journals Modulation Instability of Ion-Acoustic Waves in Plasma with Nonthermal Electrons

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Basudev Ghosh ◽  
Sreyasi Banerjee
Keyword(s):  
Acoustic Waves ◽  
Modulational Instability ◽  
Perturbation Technique ◽  
Collisionless Plasma ◽  
Multiple Scale ◽  
Ion Temperature ◽  
Nls Equation ◽  
Ion Acoustic Waves ◽  
Nonthermal Electrons ◽  
Ion Acoustic

Modulational instability of ion-acoustic waves has been theoretically investigated in an unmagnetized collisionless plasma with nonthermal electrons, Boltzmann positrons, and warm positive ions. To describe the nonlinear evolution of the wave amplitude a nonlinear Schrödinger (NLS) equation has been derived by using multiple scale perturbation technique. The nonthermal parameter, positron concentration, and ion temperature are shown to play significant role in the modulational instability of ion-acoustic waves and the formation of envelope solitons.

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