Erratum: 'Ion acoustic shock waves in presence of superthermal electrons and interaction of classical positron beam'[Phys. Plasmas 19, 032302 (2012)]
No abstract prepared.
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Engineering topics
Shah, Asif
Publications and source records attributed to Shah, Asif.
Kadomtsev-Petviashvili solitons propagation in a plasma system with superthermal and weakly relativistic effects
Two dimensional (2D) solitons are studied in a plasma system comprising of relativistically streaming ions, kappa distributed electrons, and positrons. Kadomtsev-Petviashvili (KP) equation is derived through the reductive perturbation technique. Analytical solution of the KP equation has been studied numerically and graphically. It is noticed that kappa parameters of electrons and positrons as well as the ions relativistic streaming factor have an emphatic influence on the structural as well as propagation characteristics of two dimensional solitons in the considered plasma system. Our results may be helpful in the understanding of soliton propagation in astrophysical and laboratory plasmas, specifically the interaction of pulsar relativistic wind with supernova ejecta and the transfer of energy to plasma by intense electric field of laser beams producing highly energetic superthermal and relativistic particles [L. Arons, Astrophys. Space Sci. Lib. 357, 373 (2009); P. Blasi and E. Amato, Astrophys. Space Sci. Proc. 2011, 623; and A. Shah and R. Saeed, Plasma Phys. Controlled Fusion 53, 095006 (2011)].
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Propagation of solitary waves in relativistic electron-positron-ion plasmas with kappa distributed electrons and positrons
Electrostatic ion acoustic solitary waves are studied in a plasma system comprising of relativistic ions, kappa distributed electrons, and positrons. The increase in the relativistic streaming factor and positron and electron kappa parameters cause the soliton amplitude to thrive. However, the soliton amplitude diminishes as the positron concentration is increased in the system. Our results are general and may be helpful, in understanding nonlinear phenomena in the presence of kappa distibuted electrons, positrons, and relativistically streaming ions.
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Response to ''Comment on 'Acoustic solitons in inhomogenous pair-ion plasmas''' [Phys. Plasmas 18, 054701 (2011)]
The quantity n{sub p0}(0) is different from n{sub p0}(x) and same is true for v{sub p0}(0), v{sub p0}(x). Taking these differences into account and considering the mathematical relation v{sub p0}(x)= 1/n{sub p0}(x), it can easily be shown that derivatives of these space dependent densities and velocities are linked through the relation {partial_derivative}v{sub p0}(x)/{partial_derivative}{eta}=-1/n{sub p0}{sup 2}(x){partial_derivative}n{sub p0}(x)/{partial_derivative}{eta}. We show that constraint (1) of the comment can also be transformed to derivative transformation relation. This derivative transformation relation can be used in the derivation of the KdV like equation and our model is valid for inhomogenous pair ion plasma. We mathematically and physically prove that the objections in the comment are false and baseless.
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Nonlinear quantum ion acoustic waves in a Fermi plasma
Ion acoustic waves in a homogeneous quantum plasma, comprising of positive, negative ions, and electrons, have been investigated via the Korteweg-de Vries equation. The positive and negative ions are taken inertial and electrons are taken as inertialess. It is determined that the dispersive property of quantum plasma is strongly related to the quantum diffraction parameter. The quantum diffraction parameter (H{sub e}), ion mass ratio (m), and negative ion temperature ratio ({beta}) blatantly influence the propagation and type (compressive/rarefactive) of nonlinear ion acoustic solitary wave. It is noticed that soliton amplitude follows a dual trend at higher and lower concentrations of negative ions. The theoretical calculations presented are applicable to analyze the propagation of ion acoustic waves in a quantum electron-ion plasma containing negative ions in addition.
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Acoustic solitons in inhomogeneous pair-ion plasmas
The acoustic solitons are investigated in inhomogeneous unmagnetized pair ion plasmas. The Korteweg-de Vries (KdV) like equation with an additional term due to density gradients is deduced by employing reductive perturbation technique. It is noticed that pair-ion plasma system is conducive for the propagation of compressive as well as rarefactive solitons. The increase in the temperature ratio causes the amplitude of the rarefactive soliton to decrease. However, the amplitude of the compressive solitons is found to be increased as the temperature ratio of ions is enhanced. The amplitude of both compressive and rarefactive solitons is found to be increased as the density gradient parameter is increased. The equlibrium density profile is assumed to be exponential. The numerical results are shown for illustration.
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Ion acoustic solitons in unmagnetized inhomogeneous multi-ion component plasmas with vortex distributed electrons
The ion acoustic solitons are studied in an inhomogeneous multi-ion component plasma in the presence of heavy and light adiabatic ions and two temperature electrons with vortex distribution. The modified Korteweg-de Vries equation with an additional term due to density gradients is derived by employing reductive perturbation technique. It is found that the amplitude of the soliton enhances as the concentration ratio of cold to hot electrons, density gradient parameter and ion temperature are increased in the system. The effects of mass, charge ratios of heavy to light ions and electron temperature are also investigated on the structural as well as propagation characteristics of solitary wave. The equilibrium density profile is taken to be exponential. The phase velocity of ion acoustic wave is also studied as a function of various plasma parameters. The numerical results are presented for illustration.
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Nonlinear Korteweg-de Vries equation for soliton propagation in relativistic electron-positron-ion plasma with thermal ions
The nonlinear propagation of ion-acoustic solitons in relativistic electron-positron-ion plasma comprising of Boltzmannian electrons, positrons, and relativistic thermal ions has been examined. The Korteweg-de Vries equation has been derived by reductive perturbation technique. The effect of various plasma parameters on amplitude and structure of solitary wave is investigated. The pert graphical view of the results has been presented for illustration. It is observed that increase in the relativistic streaming factor causes the soliton amplitude to thrive and its width shrinks. The soliton amplitude and width decline as the ion to electron temperature ratio is increased. The increase in positron concentration results in reduction of soliton amplitude. The soliton amplitude enhances as the electron to positron temperature ratio is increased. Our results may have relevance in the understanding of astrophysical plasmas.
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Spherical and cylindrical imploding and exploding shock waves in plasma system dominated by pair production
The propagation of ion acoustic shock waves in cylindrical and spherical geometries has been investigated. The plasma system consists of cold ions, Boltzmannian electrons and positrons. Spherical, cylindrical Korteweg-de Vries-Burger equations have been derived by reductive perturbation technique and their shock behavior is studied by employing finite difference method. Our main emphasis is on the behavior of shock as it moves toward and away from center of spherical and cylindrical geometries. It is noticed, that the shock wave strength and steepness accrues with time as it moves toward the center and shock enervates as it moves away from center. The strength of shock in spherical geometry is found to dominate over shock strength in cylindrical geometry. Positron concentration, kinematic viscosity are also found to have significant effect on the shock structure and propagation. The results may have relevance in the inertial confinement fusion plasmas.
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