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1.
Arbitrary amplitude electron acoustic (EA) solitary waves in a magnetized nonextensive plasma comprising of cool fluid electrons, hot nonextensive electrons, and immobile ions are investigated. The linear dispersion properties of EA waves are discussed. We find that the electron nonextensivity reduces the phase velocities of both modes in the linear regime: similarly the nonextensive electron population leads to decrease of the EA wave frequency. The Sagdeev pseudopotential analysis shows that an energy-like equation describes the nonlinear evolution of EA solitary waves in the present model. The effects of the obliqueness, electron nonextensivity, hot electron temperature, and electron population are incorporated in the study of the existence domain of solitary waves and the soliton characteristics. It is shown that the boundary values of the permitted Mach number decreases with the nonextensive electron population, as well as with the electron nonextensivity index, q. It is also found that an increase in the electron nonextensivity index results in an increase of the soliton amplitude. A comparison with the Vikong Satellite observations in the dayside auroral zone is also taken into account. 相似文献
2.
Anirban Guha Barin Kumar De Abhijit Choudhury Rakesh Roy 《Astrophysics and Space Science》2012,338(2):287-294
The problem of solitary electron acoustic (EA) wave propagation in a plasma with nonthermal hot electrons featuring the Tsallis
distribution is addressed. A physically meaningful nonextensive nonthermal velocity distribution is outlined. It is shown
that the effect of the nonthermal electron nonextensivity on EA waves can be quite important. Interestingly, we found that
the phase speed of the linear EA mode increases as the entropic index q decreases. This enhancement is weak for q>1, and significant for q<1. For a given nonthermal state, the minimum value of the allowable Mach numbers is lowered as the nonextensive nature of
the electrons becomes important. This critical limit is shifted towards higher values as the nonthermal character of the plasma
is increased. Moreover, our plasma model supports rarefactive EA solitary waves the main quantities of which depend sensitively
on q. This dependency (for q>1) becomes less noticeable as the nonthermal parameter decreases. Nevertheless, decreasing α yields for q<0 a different result, a trend which may be attributed to the functional form of the nonthermal nonextensive distribution.
Our study (which is not aimed at putting the ad hoc Cairns distribution onto a more rigorous foundation) suggests that a background
electron nonextensivity may influence the EA solitons. 相似文献
3.
Hamid Reza Pakzad 《Astrophysics and Space Science》2011,334(2):337-343
Nonlinear ion acoustic solitary waves (IASWs) are addressed in a weakly relativistic plasma consisting of cold ion fluid,
q-nonextensive electron velocity distribution and Boltzmann distributed positron. The Korteweg-de Vries- (KdV) equation is
derived by reductive perturbation method. We investigate the effect of nonextensive electrons on solitary waves in this medium.
It is found that only compressive solitons can be appeared in the existence of nonextensive electrons. It is shown that the
structure of soliton depend sensitively on the q-nonextensive parameter. 相似文献
4.
S. K. El-Labany W. F. El-Taibany M. M. El-Fayoumy 《Astrophysics and Space Science》2012,341(2):527-534
Propagation regimes of large-amplitude dust-ion acoustic solitary wave in a dusty plasma with nonthermal electrons are analyzed by employing the Sagdeev potential technique. Two domains of the Mach numbers are defined depending on the nonthermal and plasma parameters. The two types of soliton solution are found to be exited corresponding to certain values of the nonthermal parameter. Numerical solutions are presented that illustrate the dependence of soliton characteristics on practically interesting plasma and nonthermal parameters. The findings of this investigation could be useful in understanding the detected solitary waves in space plasma in the presence of nonthermal electrons such as electrostatic solitary structures observed in Saturn’s E-ring. 相似文献
5.
The combined effects of the obliqueness and nonextensive electrons are incorporated in the study of ion acoustic (IA) waves in a magnetized plasma. The propagation properties of two possible modes (in the linear regime) are investigated. It is found that the electron nonextensivity decreases the phase velocities of both two modes. Also obliqueness leads to increase of separation between two modes. The nonlinear evolution of IA solitary waves is governed by an energy-like equation. The influence of electron nonextensivity, obliqueness and electron population on the existence domain of solitary waves and the soliton characteristics are examined. It is shown that the existence domain of the IA soliton and its profile is significantly depended on the deviation of electrons from thermodynamic equilibrium and obliqueness. Interestingly, the present model supports compressive as well as rarefactive IA solitary waves. Our finding should elucidate the nonlinear electrostatic structures that propagate in astrophysical and cosmological plasma scenarios where nonextensive and magnetized plasma can exist; like instellar plasma stellar polytropes, solar neutrino problem, peculiar velocities of galaxy clusters, dark-matter halos, protoneutron stars, hadronic matter, quark-gluon plasma, and magnetosphere, etc. 相似文献
6.
The propagation of the nonlinear electrostatic ion acoustic solitary wave structures in two component, non relativistic, homogenous, magneto rotating plasma are studied. The inertialess electrons are assumed to follow nonextensive q velocity distribution. Small amplitude reductive perturbation technique is applied to derive Korteweg de Vries (KdV) equation and its analytical solution is presented. The effects of variation of different plasma parameters on propagation characteristics of solitary wave structure in the presence of the Coriolis force are discussed. It is observed that nonextensive parameter q modifies the structure of solitary wave structures in rotating plasmas. 相似文献
7.
The properties of propagation of small amplitude ion acoustic solitary waves (IASWs) are studied in a plasma containing cold fluid ions and multi-temperature electrons (cool and hot electrons) with nonextensive distribution. Korteweg-de Vries (KdV) equation with finite amplitude is derived using a reductive perturbation method. From the solitary solutions of KdV equation, the combined effects of nonextensivity and density ratio are studied on characteristics of ion acoustic (IA) solitary waves. Positive as well as negative polarity solitons exist. Since singularity exists for A=0 so we have also derived modified Korteweg de Vries (mKdV) equation to study the solitonic solution for critical values of physical parameters (q,f,σ). The nonextensivity of electrons (via q) and density ratio of electrons and ions (via f) and temperature ratio (σ) significantly influence the characteristics of ion acoustic solitary structures. 相似文献
8.
The positron acoustic shock and solitary wave are explored in nonextensive electron-positron-ion plasma. The plasma system under-consideration, consists of a classical positron beam, q distributed electrons and positively charged bulky ions constitute a neutralizing background. The nonlinear Korteweg-de Vries and Burger equations are derived by employing the standard reductive perturbation method. The positron acoustic wave in linear limit is also discussed for dissipative as well as nondissipative cases of nonextensive plasmas. The plasma parameters such as, the concentration of neutralizing ions background, beam velocity, temperature and q parameter of the nonextensive electrons are noticed to significantly affect the positron acoustic shock and solitary waves. Our findings may be helpful in the understanding of laboratory beam plasma interaction experiments as well as the astrophysical nonextensive plasmas interacting with positron beam. 相似文献
9.
Korteweg-de Vries (KdV) equation for electrostatic ion acoustic wave in a three component plasma containing positive and negative ions along with the nonextensive electrons is derived. Fast and slow ion acoustic modes which propagate with different velocities are excited. The effects of variation of quantities like q (nonextensive parameter), Q (mass ratio of positive to negative ion), μ (electron to positive ion number density ratio), θ i (positive ion to electron temperature ratio) and θ n (negative ion to electron temperature ratio) have been presented for fast and slow ion acoustic modes. Both compressive and rarefactive solitons are observed. It is found that the solitary excitations strongly depend on the mass and density ratios of the positive and negative ions as well as on nonextensive electron parameter. 相似文献
10.
Biswajit Sahu 《Astrophysics and Space Science》2012,338(2):251-257
The nonlinear wave structures of ion acoustic waves (IAWs) in an unmagnetized plasma consisting of nonextensive electrons
and thermal positrons are studied in bounded nonplanar geometry. Using reductive perturbation technique we have derived cylindrical
and spherical Korteweg-de Vries-Burgers’ (KdVB) equations for IAWs. The presence of nonextensive q-distributed electrons is shown to influence the solitary and shock waves. Furthermore, in the existence of ion kinematic
viscosity, the shock wave structure appears. Also, the effects of nonextensivity of electrons, ion kinematic viscosities,
positron concentration on the properties of ion acoustic shock waves (IASWs) are discussed in nonplanar geometry. It is found
that both compressive and rarefactive type solitons or shock waves are obtained depending on the plasma parameter. 相似文献
11.
Kaushik Roy Tapas Kumar Maji Malay Kumar Ghorui Prasanta Chatterjee Rajkumar Roychoudhury 《Astrophysics and Space Science》2014,352(1):151-157
Theoretically the propagation of two ion acoustic soliton interaction in a three component collisionless unmagnetized plasma which consists of electrons, positrons and cold ions, has been investigated here by employing reductive perturbation technique. In this study, q distributed electrons and Maxwell-Boltzmann distributed positrons are considered and Korteweged-de Vries (KdV) equation is derived. The KdV equation is solved to get two soliton solution by using Hirota bilinear method. The effects of the q distributed electrons on the profiles of two soliton structures and the corresponding phase shifts are investigated. It is observed that both the nonextensive parameter (q) and the ratio of positrons density and electron density (p=n p0/n e0), play a significant role in the formation and existence of two soliton and also in the nature of their phase shifts. 相似文献
12.
Uday Narayan Ghosh Prasanta Chatterjee Sanjib Kumar Kundu 《Astrophysics and Space Science》2012,339(2):255-260
The head-on collision of dust acoustic solitary waves are studied in a dusty plasma composed of dust and nonextensive distributed
ions by using the extended version of Poincaré-Lighthill-Kuo (PLK) method. The effect of the nonextensivity on the phase shift
is studied. It is found that the presence of nonextensive distributed ions plays a significant role on the collision of dust
acoustic solitary waves. 相似文献
13.
Nonlinear dust ion acoustic solitary waves (DIASW) in dusty plasma are studied incorporating kinematic viscosity, using Sagdeev’s pseudopotential approach. The effects of kinematic viscosity and the nonextensive parameter q on the features of DIASW are investigated in some detail. 相似文献
14.
A parametric survey on the propagation characteristics of the dust ion-acoustic (DIA) shock waves showing the effect of nonextesivity with nonextensive electrons in a dissipative dusty plasma system has been carried out using the reductive perturbation technique. We have considered continuity and momentum equations for inertial ions, q-distributed nonextensive electrons, and stationary charged dust grains, to derive the Burgers equation. It has been found that the basic features of DIA shock waves are significantly modified by the effects of electron nonextensivity and ion kinematic viscosity. Depending on the degree of nonextensivity of electrons, the dust ion-acoustic shock structures exhibit compression and rarefaction. The implications of our results would be useful to understand some astrophysical and cosmological scenarios like stellar polytropes, hadronic matter and quark-gluon plasma, protoneutron stars, dark-matter halos, etc., where effects of nonextensivity can play the significant roles. 相似文献
15.
Nonlinear dynamics of electron acoustic waves (EAWs) in a plasma consisting of stationary ions, cool inertial electrons and hot electrons having a nonextensive distribution is studied. Under transverse perturbations, the nonlinear wave can be described by the general form of the Davey-Stewartson (DS) equations. The reductive perturbation technique is employed to derive Davey-Stewartson equations. From the solutions of these equations, amplitude modulation properties and stability regions of EAWs are studied in two-dimensional plasma. Further, the influence of nonextensivity of hot electrons (via q) on the characteristics of EAWs has been analysed. 相似文献
16.
The problems of large amplitude double layers are discussed using Sagdeev’s pseudo-potential technique for a dusty plasma comprising two temperature isothermal ions and nonextensive nonthermal velocity distributed electron. For different sets of plasma parameter values, the Sagdeev potential V(?) has been plotted. It is found that nonextensive q parameter plays a significant role in determining the shape and size of large amplitude double layers. Also, it is observed that the existence of large amplitude double layers depends on different plasma parameters. 相似文献
17.
Nonlinear propagation of dust-acoustic (DA) waves in a magnetized dusty plasma, consisting of negatively charged mobile dust, Maxwellian ions and two distinct temperature nonextensive electrons (following nonextensive q-distribution each), has been studied and analyzed by deriving and solving the Korteweg-de-Vries (K-dV) equation. According to the outcomes of the investigation, the basic characteristics of the DA solitary profiles are found to be strongly modified by the external magnetic field, nonextensivity of the electrons and the respective number densities of the two species of electrons. The results of this investigation can be applied in both laboratory and astrophysical plasma scenarios for understanding the basic features of the localized electrostatic dust-acoustic solitary waves (DASWs). 相似文献
18.
Detection of ionospheric perturbation due to a soft gamma ray repeater SGR J1550-5418 by very low frequency radio waves 总被引：1，自引：0，他引：1
Sushanta K. Mondal Sandip K. Chakrabarti Sudipta Sasmal 《Astrophysics and Space Science》2012,338(2):259-264
The properties of cylindrical and spherical dust acoustic (DA) solitary and shock waves in an unmagnetized electron depleted
dusty plasma consisting of inertial dust fluid and ions featuring Tsallis statistics are investigated by employing the reductive
perturbation technique. A Korteweg-de Vries Burgers (KdVB) equation is derived and its numerical solution is obtained. The
effects of ion nonextensivity and dust kinematic viscosity on the basic features of DA solitary and shock waves are discussed
in nonplanar geometry. It is found that nonextensive nonplanar DA waves behave quite differently from their one-dimensional
planar counterpart. 相似文献
19.
Hamid Reza Pakzad 《Astrophysics and Space Science》2011,334(1):55-60
Ion acoustic shock waves (IASWs) are studied in a plasma consisting of nonextensive electrons and ions. The dissipation is
taken into account the kinematic viscosity among the plasma constituents. The Korteweg-de Vries-Burgers (KdV-Burgers) equation
is derived by reductive perturbation method. Shock waves are solutions of KdV-Burgers equation. It is shown that acceptable
values of q-parameter (where q stands for the electron nonextensive parameter) are more than 3 in a weakly nonlinear analysis. We have found that the amplitude
of shock waves decreases by an increasing q-parameter. 相似文献
20.
Bifurcations of dust acoustic solitary waves and periodic waves in an unmagnetized plasma with q-nonextensive velocity distributed ions are studied through non-perturbative approach. Basic equations are reduced to an ordinary differential equation involving electrostatic potential. After that by applying the bifurcation theory of planar dynamical systems to this equation, we have proved the existence of solitary wave solutions and periodic wave solutions. Two exact solutions of the above waves are derived depending on the parameters. From the solitary wave solution and periodic wave solution, the effect of the parameter (q) is studied on characteristics of dust acoustic solitary waves and periodic waves. The parameter (q) significantly influence the characteristics of dust acoustic solitary and periodic structures. 相似文献