共查询到20条相似文献，搜索用时 46 毫秒
1.
A study is presented of the nonlinear self-modulation of low-frequency electrostatic dust acoustic waves (DAWs) propagating in a dusty plasma, within the theoretical framework of the nonextensive statistics proposed by Tsallis. Using the reductive perturbation method (RPM), the nonlinear Schrödinger equation (NLSE) which governs the modulational instability (MI) of the DAWs is obtained. The presence of the nonextensive electron/ion distribution is shown to influence the MI of the waves. Furthermore it is observed that nonextensive distributed ions has more effect on the MI of the DAW than electrons. 相似文献
2.
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
3.
Rabia Amour Mouloud Tribeche Taha Houssine Zerguini 《Astrophysics and Space Science》2012,338(1):57-61
Nonlinear dust-acoustic (DA) shock waves are addressed in a nonextensive dusty plasma exhibiting self-consistent nonadiabatic
charge variation. Our results reveal that the amplitude, strength and nature of the DA shock waves are extremely sensitive
to the degree of ion nonextensivity. Significant differences in the potential function occur for very small changes in the
value of the nonextensive parameter. Stronger is the ions correlation, more important is the charge variation induced nonlinear
wave damping. 相似文献
4.
S. K. Zaghbeer H. H. Salah N. H. Sheta E. K. El-Shewy A. Elgarayh 《Astrophysics and Space Science》2014,353(2):493-500
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
5.
Our recent analysis on nonlinear nonextensive dust-acoustic waves (DA) [Amour and Tribeche in Phys. Plasmas 17:063702, 2010]
is extended to include self-consistent nonadiabatic grain charge fluctuation. The appropriate nonextensive electron charging
current is rederived based on the orbit-limited motion theory. Our results reveal that the amplitude, strength and nature
of the nonlinear DA waves (solitons and shocks) are extremely sensitive to the degree of ion nonextensivity. Stronger is the
electron correlation, more important is the charge variation induced nonlinear wave damping. The anomalous dissipation effects
may prevail over that dispersion as the electrons evolve far away from their Maxwellian equilibrium. Our investigation may
be of wide relevance to astronomers and space scientists working on interstellar dusty plasmas where nonthermal distributions
are turning out to be a very common and characteristic feature. 相似文献
6.
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
7.
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
8.
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
9.
A weakly nonlinear analysis is carried out to derive a Korteweg–de Vries-Burgers-like equation for small, but finite amplitude,
ion-acoustic waves in a dissipative plasma consisting of weakly relativistic ions, thermal positrons and nonextensive electrons.
The travelling wave solution has been acquired by employing the tangent hyperbolic method. Our results show that in a such
plasma, ion-acoustic shock waves, the strength and steepness of which are significantly modified by relativistic, nonextensive
and dissipative effects, may exist. Interestingly, we found that because of ion kinematic viscosity, an initial solitonic
profile develops into a shock wave. This later evolves towards a monotonic profile (dissipation-dominant case) as the electrons
deviate from their Maxwellian equilibrium. Our investigation may help to understand the dissipative structures that may occur
in high-energy astrophysical plasmas. 相似文献
10.
The nonlinear propagation of ion-acoustic waves is studied in an unmagnetized collissionless electronegative plasma, whose constituents are the inertial warm positive/negative ions and q-distributed nonextensive electrons. The latter have strong impact on the linear dispersion relation. However, for nonlinear analysis, a reductive perturbation technique is employed to derive a Korteweg-de Vries (KdV) equation accounting for nonthermal electrons in nonplanar geometries. Numerically, the effects of various plasma parameters, such as, the nonextensive parameter (q), the negative-to-positive ion mass ratio (α), the electron-to-positive ion number density ratio (μ), the positive ion-to-electron temperature ratio (θ i ) and negative ion-to-electron temperature ratio (θ n ), have been examined on the nonplanar compressive/rarefactive fast ion-acoustic solitons (where the wave phase speed is taken as λ>1). The relevance of our findings involving plasma wave excitations should be useful both for space and laboratory plasmas, where two distinct groups of ions besides the electrons, are present. 相似文献
11.
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
12.
Mustapha Bacha Soufiane Boukhalfa Mouloud Tribeche 《Astrophysics and Space Science》2012,341(2):591-595
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
13.
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
14.
Hamid Reza Pakzad 《Astrophysics and Space Science》2014,353(2):551-557
Properties of dust-ion acoustic solitary waves (DIASWs) in dusty plasmas composed of nonextensive electrons, cold fluid ions and stationary dust particles are investigated. The possibility of soliton formation and the effect of nonextensivity of the electron distribution on the soliton characters are studied using the pseudo-potential method. Regions of parameters in which a solitary wave can be propagated in the plasma is analyzed too. It is found that the solitary excitations strongly depend on the electron-ion density ratio (μ), Mach numbers (M) as well as the nonextensive parameter (q). It is shown that the domain of allowed Mach numbers depends drastically on the plasma parameters and especially on the electron nonextensivity. It is found that beyond a threshold value of the nonextensive parameter (q), dust-ion acoustic solitons are admitted. 相似文献
15.
M.J. Giles 《Planetary and Space Science》1979,27(5):691-697
The instability of electrostatic ion cyclotron waves to low frequency density modulations is considered and nonlinear equations are derived which describe its development in terms of a coherent four wave interaction. A dispersion relation for the linear phase of the instability is obtained and threshold conditions for marginal stability determined. It is shown, using data from recent optical observations, that the conditions necessary for the instability to occur in the auroral plasma would probably be satisfied and that modulational frequencies in agreement with the observations are obtained for plausible wave amplitudes. The nonlinear development of the instability is then studied and it is shown that substantial modulation can occur. It is suggested therefore that this instability could lead to the development of a strongly turbulent state. 相似文献
16.
Nonlinear propagation of dust-acoustic waves in an unmagnetized dusty plasma consisting of negatively charged mobile dust, nonextensive ions following nonextensive q-distribution and two distinct temperature superthermal electrons following superthermal kappa distribution each, is investigated by employing lower and higher order nonlinear equations, namely the Korteweg-de-Vries (K-dV), the modified Korteweg-de-Vries (mK-dV) and the Gardner equations. The characteristic features of the hump (positive potential) and dip (negative potential) shaped dust-acoustic (DA) Gardner solitons are found to exist beyond the K-dV limit. The effects of two superthermal temperature electrons and ions nonextensivity on the basic characteristics of DA K-dV, mK-dV and Gardner solitons have also been investigated. It has been found that the DA Gardner solitons exhibit either negative or positive potential solitons only for q<q c where, q c is the critical value of the nonextensive parameter q. The possible applications of our results in understanding the localized nonlinear electrostatic structures existing in solar atmosphere, Saturn’s magnetosphere etc. (where the tails of the high energetic particles at different temperatures follow power-law like distribution) are also briefly discussed. 相似文献
17.
Solar System Research - Within the framework of Tsallis nonextensive statistics, the criteria for the Jeans gravitational instability are derived for a self-gravitating protoplanetary disk, whose... 相似文献
18.
According to a widespread point of view, intensive electrostatic structures in the E‐region of the auroral ionosphere can be a consequence of the excitation of the modified two‐stream or Farley‐Buneman (FB) plasma turbulence. But in spite of the successes of the theoretical and experimental research of the auroral radar scattering, it is impossible to explain the existence of auroral echoes with large aspect angles (> 2 deg.), the wave propagation perpendicular to the electron drift velocity and wave scales less than 1 m. In this paper the coherent nonlinear interactions of three and four electrostatic FB‐waves are considered analytically and numerically. The evolution of the nonlinear waves is described by a system of magnetohydrodynamic equations. 1) It is shown that the interaction of three and four coherent waves is the main physical mechanism which leads to the saturation of the FB‐instability. 2) If no dissipative and dispersive effects occur, an explosive instability may be excited. 3) The main result of the interaction of coherent waves is the generation of nonlinear waves and nonlinear structures when the waves are damped linearly and propagate perpendicular to the electron drift velocity. This region corresponds to large aspect angles of the small‐scale waves. 4) Further, the wave interaction causes a nonlinear stabilization of the growth of the high‐frequency waves and a formation of local density structures of the charged particles. The results of the numerical models allow to analyse the possibility of scenarios of the two‐stream plasma instability in the collisional auroral E‐region. 相似文献
19.
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
20.
The effect of a magnetic field on the nonlinear capillary instability of a fluid jet is examined using the method of multiple scales. It is a well-known result that a sufficiently strong magnetic field can, in the limit of zero viscosity and resistivity, completely suppress the linear capillary instability. It turns out that while the nonlinear (modulational) instability cannot be completely suppressed, the presence of a magnetic field does greatly increase the range of stable wave numbers. 相似文献