Abstract:Using the reductive perturbation technique (RPT), the nonlinear propagation of magnetosonic solitary waves in an ultracold, degenerate (extremely dense) electron-positron (EP) plasma (containing ultracold, degenerate electron, and positron fluids) is investigated. The set of basic equations is reduced to a Korteweg-de Vries (KdV) equation for the lowest-order perturbed magnetic field and to a KdV type equation for the higher-order perturbed magnetic field. The solutions of these evolution equations are obtaine… Show more
“…We seek the steady state solitary wave solution of the KdV equation (25). For that we introduce the moving co-ordinate h x t =u , We now examine the characteristics of solitary KAWs described by equation (25). It is obvious from equation 26that the nonlinearity coefficient A is negative for all possible values of r, s F and obliqueness l .…”
Section: Soliton Solution and Discussionmentioning
confidence: 99%
“…In recent years, the investigation of different types of nonlinear wave propagation in degenerate e-p [23][24][25] as well as e-p-i [7,26,27] plasmas has attracted the attention of several authors. Taibany and Mamun [23] have reported the existence of compressive (rarefactive) electromagnetic solitons corresponding to the fast (slow) magnetosonic perturbation modes in an ultrarelativistic, ultracold, degenerate e-p plasma.…”
Through the use of a reductive perturbation technique, solitary kinetic Alfvén waves (KAWs) are investigated in a low but finite b (particle-to-magnetic pressure ratio) dense electron-positron-ion plasma where electrons and positrons are degenerate. The degenerate plasma model considered here permits the existence of sub-Alfvénic compressive solitary KAWs. The influence of r (equilibrium positron-to-ion density ratio), s F (electron-to-positron Fermi temperature ratio), b and obliqueness parameter l z on various characteristics of solitary KAWs are examined through numerical plots. We have shown that there exists a critical value of l z at which a soliton width attains its maximum value which decreases with an increase in r and s. F It is also found that solitons with a higher energy propagate more obliquely in the direction of an ambient magnetic field. The results of the present investigation may be useful for understanding low frequency nonlinear electromagnetic wave propagation in magnetized electron-positron-ion plasmas in dense stars. Specifically, the relevance of our investigation to a pulsar magnetosphere is emphasized.
“…We seek the steady state solitary wave solution of the KdV equation (25). For that we introduce the moving co-ordinate h x t =u , We now examine the characteristics of solitary KAWs described by equation (25). It is obvious from equation 26that the nonlinearity coefficient A is negative for all possible values of r, s F and obliqueness l .…”
Section: Soliton Solution and Discussionmentioning
confidence: 99%
“…In recent years, the investigation of different types of nonlinear wave propagation in degenerate e-p [23][24][25] as well as e-p-i [7,26,27] plasmas has attracted the attention of several authors. Taibany and Mamun [23] have reported the existence of compressive (rarefactive) electromagnetic solitons corresponding to the fast (slow) magnetosonic perturbation modes in an ultrarelativistic, ultracold, degenerate e-p plasma.…”
Through the use of a reductive perturbation technique, solitary kinetic Alfvén waves (KAWs) are investigated in a low but finite b (particle-to-magnetic pressure ratio) dense electron-positron-ion plasma where electrons and positrons are degenerate. The degenerate plasma model considered here permits the existence of sub-Alfvénic compressive solitary KAWs. The influence of r (equilibrium positron-to-ion density ratio), s F (electron-to-positron Fermi temperature ratio), b and obliqueness parameter l z on various characteristics of solitary KAWs are examined through numerical plots. We have shown that there exists a critical value of l z at which a soliton width attains its maximum value which decreases with an increase in r and s. F It is also found that solitons with a higher energy propagate more obliquely in the direction of an ambient magnetic field. The results of the present investigation may be useful for understanding low frequency nonlinear electromagnetic wave propagation in magnetized electron-positron-ion plasmas in dense stars. Specifically, the relevance of our investigation to a pulsar magnetosphere is emphasized.
“…Most of the astrophysical and space plasmas are permeated by the magnetic field [10,[31][32][33][34][35][36]. Accordingly, the effect of the external magnetic field plays an important role.…”
Section: Introductionmentioning
confidence: 99%
“…The propagation of magnetized IASWs by the KdV equation which has both the dispersive term and nonlinear term has been examined. The nonlinear propagation of magnetosonic solitary waves in an ultracold, degenerate EP plasma was investigated [33].…”
The nonlinear propagation of ion-acoustic Gardner solitons (GSs) and double layers (DLs) in electron-positron-ion (EPI) plasma in the presence of an external static magnetic field has been examined. The Korteweg-de Vries (KdV), modified KdV (mKdV), and Gardner equations have been derived by the reductive perturbation technique. It is seen that the amplitude, polarity, speed, width of such solitons are significantly modified by the species densities and by the obliquity angle. Compressive or rarefactive KdV solitons are obtained, but only compressive solitons are obtained in the mKdV case, wherever Gardner positive and negative DLs exist. The results of our present investigation may be useful for understanding the nonlinear wave propagation in dense quantum plasmas such as those existing in white dwarfs, neutron stars and intense laser-solid matter interaction experiments as an example of laboratory plasmas.
“…When a plasma is cooled to a relatively low temperature or its number density is relatively high, the thermal de Broglie wavelength of the charged particles becomes comparable to the dimension of the distance between the charged particles. Accordingly, quantum effects should be considered in dense plasmas (Chandra & Ghosh 2012;Sahu & Ghosh 2013;Wang, Lü & Eliasson 2013a;Wang, Shukla & Eliasson 2013b;El-Labany et al 2014;Irfan, Ali & Mirza 2014;Saha & Chatterjee 2014;Wang & Eliasson 2014). Quantum effects, together with those of the ion kinematic viscosity (Roy, Misra & Chatterjee 2008;Han et al 2011) and non-planar (Sabry, Moslem & Shukla 2009) or weakly nonlinear or arbitrarily nonlinear (Ali et al 2007) quantum ion-acoustic waves have been intensively studied in quantum EPI plasmas.…”
Two-dimensional nonlinear magnetosonic solitary and shock waves propagating perpendicular to the applied magnetic field are presented in quantum electron–positron–ion plasmas with strongly coupled classical ions and weakly coupled quantum electrons and positrons. The generalized viscoelastic hydrodynamic model is used for the ions and a quantum hydrodynamic model is introduced for the electrons and positrons. In the weakly nonlinear limit, a modified Kadomstev–Petviashvili (KP) equation with a damping term and a KP–Burgers equation have been derived in the kinetic regime and hydrodynamic regime, respectively. The analytical and numerical solutions of the modified KP and KP–Burgers equations are also presented and analysed with the typical parameters of a white dwarf star and pulsar magnetosphere, which show that the quantum plasma beta and the variation of positron number density have remarkable effects on the propagation of magnetosonic solitary and shock waves.
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