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1.
Propagation of nonlinear dust-acoustic waves in a magnetized collisionless plasma having positively, negatively charged dust grains and nonextensive distributed electrons and ions has been investigated. A reductive perturbation method is used to obtain a nonlinear Korteweg-de Vries (KdV) equation describing the model. The dynamics of the modulational instability gives rise to the formation of rogue waves that is described by a nonlinear Schrödinger equation. The dependence of rogue waves profiles on positive and negative charged dust cyclotron frequencies, nonextensive parameters of electrons and ions is investigated numerically. The result of the present investigation may be applicable to some plasma environments, such as cometary tails and upper mesosphere.  相似文献   

2.
Ion acoustic (IA) solitary and rogue waves are studied in an unmagnetized plasma consisting of non-degenerate warm ions, relativistically degenerate electrons and positrons. By using the reductive perturbation technique, the evolution of IA solitary waves is described by the Korteweg-de Vries (KdV) equation. However, when the frequency of the carrier wave is much smaller than the ion plasma frequency then the KdV equation is also used to study the nonlinear evolution of modulationally unstable modified IA wavepackets through the derivation of nonlinear Schrödinger equation. It is found that the characteristics of the IA solitary and rogue waves are substantially influenced by the intrinsic plasma parameters. The relevance of the present investigation involving IA solitary and rogue waves in astrophysical plasma environments is also highlighted.  相似文献   

3.
Magnetosonic rogue waves (rogons) are investigated in an electron-ion plasma by deriving the nonlinear Schrödinger (NLS) equation for low frequency limit. The first- and second-order rogue wave solutions of the NLS equation are obtained analytically and examined numerically. It is found that for dense plasma and stronger magnetic field the nonlinearity decreases, which causes the rogon amplitude becomes shorter. However, the electron temperature pumping more energy to the background waves which are sucked to create rogue waves with taller amplitudes.  相似文献   

4.
The nonlinear properties of small amplitude electron-acoustic solitary waves (EAWs) in a homogeneous system of unmagnetized collisionless plasma consisted of a cold electron fluid and isothermal ions with two different temperatures obeying Boltzmann type distributions have been investigated. A reductive perturbation method was employed to obtain the Kadomstev-Petviashvili (KP) equation. At the critical ion density, the KP equation is not appropriate for describing the system. Hence, a new set of stretched coordinates is considered to derive the modified KP equation. Moreover, the solitary solution, soliton energy and the associated electric field at the critical ion density were computed. The present investigation can be of relevance to the electrostatic solitary structures observed in various space plasma environments, such as Earth’s magnetotail region.  相似文献   

5.
The formation and propagation of dust-acoustic (DA) solitary and rogue waves are studied in a non-relativistic degenerate Thomas-Fermi thermal dusty plasma incorporating transverse velocity perturbation effects. The electrons and ions are described by the Thomas-Fermi density distributions, whereas the dust grains are taken as dynamic and classical. By using the reductive perturbation technique, the cylindrical Kadomtsev-Petviashvili (CKP) equation is derived, which is then transformed into a Korteweg-deVries (KdV) equation by using appropriate variable transformations. The latter admits a solitary wave solution. However, when the carrier waves frequency is much smaller than the dust plasma frequency, the DA waves evolve into the nonlinear modulation instability, generating modulated wave packets in the form of Rogue waves. For the study of DA-rogue waves, the KdV equation is transformed into a self-focusing nonlinear Schrödinger equation. The variation of dust temperature and the electron density affects the nonlinearity and dispersion coefficients which suppress the amplitudes of the DA solitary and rogue waves. The present results aim to describe the nonlinear electrostatic excitations in astrophysical degenerate dense plasma.  相似文献   

6.
The nonlinear properties of small amplitude dust-acoustic solitary waves (DAWs) in a homogeneous unmagnetized plasma having electrons, singly charged ions, hot and cold dust species with Boltzmann distributions for electrons and ions have been investigated. A reductive perturbation method was employed to obtain the Kadomstev-Petviashvili (KP) equation. The effects of the presence of charged hot and cold dust grains on the nature of DAWs were discussed. Moreover, the energy of two temperatures charged dusty grains were computed. The present investigation can be of relevance to the electrostatic solitary structures observed in various space plasma environments.  相似文献   

7.
Ion-acoustic rogue waves (IARWs) are addressed in a two-component plasma with a q-nonextensive electron velocity distribution. A weakly nonlinear analysis is carried out to derive a Korteweg-de Vries (K-dV) equation with a particular emphasis on its application to the IARWs. This K-dV equation is transformed to a nonlinear Schr?dinger equation, provided that the frequency of the carrier wave is much smaller than the ion plasma frequency. Interestingly, it is found that the IARWs may be drastically affected by electron nonextensivity depending on whether the entropic index q is positive or negative. In view of the crucial importance of RWs in space environments, our results should be useful in understanding the basic features of the nonextensive IARGs that may occur in space plasmas.  相似文献   

8.
Rogue wave in a collisionless, unmagnetized electronegative plasma is investigated. For this purpose, the basic set of fluid equations is reduced to the Korteweg-de Vries (KdV) equation. However, when the frequency of the carrier wave is much smaller than the ion plasma frequency then the KdV equation is also used to study the nonlinear evolution of modulationally unstable modified ion-acoustic wavepackets through the derivation of the nonlinear Schr?dinger (NLS) equation. In order to show that the characteristics of the rogue wave is influenced by the plasma parameters, the relevant numerical analysis of the NLS equation is presented. The relevance of our investigation to the Titan’s atmosphere is discussed.  相似文献   

9.
The multiple scales perturbation theory is applied to a system of dispersive waves including plasma waves (ion-acoustic waves). Assuming the amplitudes of waves are slowly varying function of space and time, we find that long-time slow modulation of the complex amplitude can be described by the non-linear Schrödinger equation. This result agrees with that obtained by Shimizu and Ichikawa using the reductive perturbation theory, and agrees exactly with the nonrelativistic limit of the nonlinear Schrödinger equation obtained by Nejoh using the stretching method.  相似文献   

10.
We have studied the nonlinear propagation of dust ion-acoustic (DIA) waves in a dusty multi-ion dense plasma (with the constituents being degenerate, either non-relativistic or ultra-relativistic) and the propagation of such waves have been investigated by the reductive perturbation method. From the stationary solution of the Korteweg de-Vries (K-dV) equation and Burgers’ equation the nonlinear waves (specially, solitary and shock waves) have been found to be formed in the dusty plasma system under consideration. It has shown that the basic features of these waves are significantly modified by both the positive and negative ions and dust number densities, the degenerate of the constituents. The implications of our results have been briefly discussed.  相似文献   

11.
The nonlinear propagation of ion-acoustic solitary and shock waves in a dissipative, nonplanar quantum plasma comprised of electrons, positrons, and ions are studied. A modified Korteweg-de Vries Burgers equation is derived in the limit of low frequency and long wavelength by taking into account the kinematic viscosity among the plasma constituents. It is shown that this plasma system supports the propagation of both compressive and rarefactive nonlinear waves. The effects of variation of various plasma parameters on the time evolution of nonplanar solitary waves, the profile of shock waves, and the nonlinear structure induced by the collision of solitary waves are discussed. It is found that these parameters have significant effects on the properties of nonlinear waves in cylindrical and spherical geometries, and these effects for compressive and rarefactive nonlinear waves are obviously different.  相似文献   

12.
The head-on collision between positron acoustic solitary waves (PASWs) as well as the production of rogue waves (RWs) in homogeneous and PASWs in inhomogeneous unmagnetized plasma systems are investigated deriving the nonlinear evolution equations. The plasmas are composed of immobile positive ions, mobile cold and hot positrons, and hot electrons, where the hot positrons and hot electrons are assumed to follow the Kappa distributions. The evolution equations are derived using the appropriate coordinate transformation and the reductive perturbation technique. The effects of concentrations, kappa parameters of hot electrons and positrons, and temperature ratios on the characteristics of PASWs and RWs are examined. It is found that the kappa parameters and temperature ratios significantly modify phase shifts after head-on collisions and RWs in homogeneous as well as PASWs in inhomogeneous plasmas. The amplitudes of the PASWs in inhomogeneous plasmas are diminished with increasing kappa parameters, concentration and temperature ratios. Further, the amplitudes of RWs are reduced with increasing charged particles concentration, while it enhances with increasing kappa- and temperature parameters. Besides, the compressive and rarefactive solitons are produced at critical densities from KdV equation for hot and cold positrons, while the compressive solitons are only produced from mKdV equation for both in homogeneous and inhomogeneous plasmas.  相似文献   

13.
Nonlinear dynamics of electron-acoustic solitary waves in a magnetized plasma whose constituents are cold magnetized electron fluid, hot electrons featuring Tsallis distribution, and stationary ions are examined. The nonlinear evolution equation (i.e., Zakharov–Kuznetsov (ZK) equation), governing the propagation of EAS waves in such plasma is derived and investigated analytically and numerically, for parameter regimes relevant to the dayside auroral zone. It is revealed that the amplitude, strength and nature of the nonlinear EAS waves are extremely sensitive to the degree of the hot electron nonextensivity. Furthermore, the obtained results are in good agreement with the observations made by the Viking satellite.  相似文献   

14.
The effect of large Larmor radius on the nonlinear behaviour of Alfvén waves propagating parallel to a uniform magnetic field in a compressible fluid is investigated with the aid of LLR-MHD equations. It is shown that asymptotic evolution of these waves is governed by the modified nonlinear Schrödinger equation. The dispersion is provided by the large Larmor radius effect in the magnetic field equation. It is suggested that these calculations can have a bearing on the investigation of the structure of MHD waves in both laboratory and space plasmas, e.g., imploding pinches, laser-blow-off plasma experiment, recent barium releases in the magnetosphere, plasma flow near small planetary bodies such as comets and plasma dynamic near collisionless shock fronts.  相似文献   

15.
Linear and nonlinear dust drift waves are investigated in the presence of kappa distributed electrons and ions. The dispersion characteristics of linear waves show that the phase velocity decreases with the inclusion of highly energetic particles in the tail of the distribution. In the nonlinear regime, a nonlinear partial differential equation is obtained in the long wave length limit. A stationary solution of this equation in the form of solitary waves is discussed and noticed that the amplitude of the solitary pulse decreases with the increase of superthermal particle’s effect, and its width expands. Further, it is found that speed limit of the nonlinear structures is also modified in the non-Maxwellian plasma. Theoretically obtained results are applied to Saturn’s’ dusty plasma environment. It is also pointed out that the present results can be helpful for further understanding of space plasmas.  相似文献   

16.
The modulational instability of the weakly nonlinear longitudinal Langmuir as well as the transverse electromagnetic waves, propagation in the relativistic plasma without the static fields is described. The nonlinear Schrödinger equation taking account of the nonlinear Landau damping for these waves has been derived by means of the relativistic Vlasov and Maxwell equations. The plasma with the weakly relativistic temperature and that with an ultrarelativistic one has been investigated. In the first case, for the electron-proton plasma with the temperature more than 2.3 KeV we found the regional change of the wave numbers for which the soliton of two types, subsonic and supersonic, can exist. The soliton of the transverse waves can exist when the group velocity of the waves is between the thermal velocity of the electron and ion and the length of the linear waves is less than 2c/ pi .In the second case the regions of the wave numbers, with the solitons of the Langmuir and transverse waves have been determined.The nonlinear waves in the electron-positron plasma and the waves with the phase velocity, which is about the light one, are also considered in the following paper.  相似文献   

17.
Arbitrary amplitude ion-acoustic solitary waves propagating in a magnetized plasma composed of positive ions, superthermal electrons and positrons are investigated. For this purpose, the ions are represented by the hydrodynamical fluid equations while the non-Maxwellian electrons and positrons densities are assumed to follow kappa (κ) distribution. The basic equations are reduced to a pseudoenergy-balance equation. Existence conditions for large amplitude solitary waves are presented. The analytical and numerical analysis of the latter show that the ion-acoustic solitary wave can propagate only in the subsonic region in our plasma system and it is significantly influenced by the plasma parameters. The present analysis could be helpful for understanding the nonlinear ion-acoustic solitary waves propagating in interstellar medium and pulsar wind, which contain an excess of superthermal particles.  相似文献   

18.
When account is taken of the finite resistivity, energy equation, and generalized Ohm's law, it can be shown that the propagation of nonlinear magnetosonic waves in a warm plasma is described by a KdV-Burgers' equation. The stationary shock solutions for the latter are discussed. It is suggested that shocks may be responsible for the observed discontinuities in MHD fluctuations in the solar atmosphere.  相似文献   

19.
A theoretical investigation is carried out to analyse the propagation of ion acoustic (IA) waves in a magnetized bi-ion plasma having two populations of fluid ions and kappa-distributed electrons. The propagation properties of all possible modes (in the linear regime) are investigated. The nonlinear evolution of the IA solitary waves is governed by a Korteweg-de Vries (KdV)-like equation. The influence of obliqueness, magnitude of the magnetic field, ion polarity and electron superthermality on the IA waves is then examined. Our findings should aid in understanding the nonlinear electrostatic excitations that may propagate in spatial magnetized plasmas.  相似文献   

20.
Linear and nonlinear analysis of low frequency magnetoacoustic waves propagating at an angle θ with the ambient magnetic field are investigated in dense electron-positron-ion (e-p-i) plasmas using the quantum magnetohydrodynamic (QMHD) model. In this regard, a quantum Kadomtsev-Petviashvili-Burgers (KPB) equation is derived in the small amplitude limit. The stability of KPB equation is also presented. The variation of the nonlinear fast and slow magnetoacoustic shock waves with the positron concentration, kinematic viscosity, obliqueness parameter θ, and the magnetic field, are also investigated. It is observed that the aforementioned plasma parameters significantly modify the propagation characteristics of two dimensional nonlinear magnetoacoustic shock waves in dissipative quantum magnetoplasmas. The relevance of the present investigation with regard to dense astrophysical environments is also pointed out.  相似文献   

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