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1.
The properties of small but finite amplitude dust acoustic (DA) shock waves are studied in a charge varying dusty plasma with ions and electrons having kappa velocity distribution. We obtain the global Debye length including the influence of suprathermality effects and dust charge fluctuations. It is shown that the effects of suprathermality of ions/electrons and dust charge fluctuation significantly modify the basic properties of DA shock wave. We observe that only negative DA shock waves will be excited in this model. The amplitude of DA shock wave increases with deviation of electrons or ions from Maxwellian distribution via decrease of spectral index, κ j (j=i,e denotes, ions and electrons, respectively). Also, it is indicated that the amplitude and steepness of the shock front decreases with an increase in the ion temperature. 相似文献
2.
Dust acoustic (DA) solitary wave existence conditions are investigated for positively charged dust particles in the presence
of nonthermal electrons. Once Sagdeev pseudo-potential derived through fluid equations, for large amplitude DA waves, the
lower limit on Mach number is calculated analytically using the necessary condition for the solitary waves existence. The
double layers conditions provides the upper limit on Mach number. This allowed us to numerically investigate the effect of
the temperature, density and nonthermal parameters on the solitary waves’ characteristics. The present study is devoted to
a complex plasma subject to ultraviolet radiations such as the one in the lower earth’s ionosphere. 相似文献
3.
Nonlinear electron-acoustic solitary waves (EASWs) are studied using Sagdeev’s pseudo-potential technique in a collisionless
unmagnetized plasma consisting of a cold electron fluid, nonthermal hot electrons and stationary ions. It is shown that the
presence of fast nonthermal electrons may modify the parametric region where electron-acoustic solitons may exist. Our investigation
is of wide relevance to astronomers and space scientists working on interstellar space plasmas. 相似文献
4.
A.A. Mamun 《Astrophysics and Space Science》1999,268(4):443-454
A rigorous theoretical investigation has been made of arbitrary amplitude dust-acoustic solitary structures in an unmagnetized
three-component dusty plasma whose constituents are an inertial charged dust fluid and Boltzmann distributed ions and electrons.
The pseudo-potential approach and the reductive perturbation technique are employed for this study. It is found from both
weakly and highly nonlinear analyses that the dusty plasma model can support solitary waves only with negative potential but
not with positive potential. The effects of equilibrium free electron density and its temperature on these solitary structures
are discussed. The implications of these results to some astrophysical and space plasma systems, especially to planetary ring-systems
and cometary tails, are briefly mentioned.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
H. Alinejad 《Astrophysics and Space Science》2012,339(2):249-254
The effects of dust polarity and superthermal electrons are incorporated in the study of dust ion-acoustic (DIA) solitary
waves (SWs) as well double layers (DLs) in a dusty plasma containing warm adiabatic ions, superthermal electrons, and arbitrarily
(positively or negatively) charged immobile dust. Based on the energy-like integral equation, a new relationship between the
localized electrostatic disturbances and dust polarity is derived. It is shown that there exists rarefactive SWs and DLs with
qualitatively different structures in a way that depends on the population of superthermal electrons. As the electrons evolve
their thermodynamic equilibrium, the localized structures are found with larger amplitude. It is also found that their amplitude
increases (decreases) with the increase in the negative (positive) dust number density. 相似文献
6.
Making use of the Sagdeev pseudo-potential approach, we derive the energy like equation for dust-acoustic (DA) solitary waves in a complex plasma having negatively charged cold dust, and electrons/ions featuring the Tsallis distribution. The effects of electron and ion nonextensivity on the DA soliton profile are examined. It is shown that depending on the strength of particle nonextensivity, our plasma model may admit compressive as well as rarefactive DA solitary waves. Our results complement previously published results on this problem. 相似文献
7.
H. Alinejad 《Astrophysics and Space Science》2011,331(2):611-618
The effects of dust charge fluctuations and deviations from isothermality of electrons are incorporated in the study of nonlinear
dust ion-acoustic waves. Deviations from isothermality of electrons are included in this model as a result of nonlinear resonant
interaction of the electrostatic wave potential with electrons during its evolution. The basic properties of stationary structures
are studied by employing the reductive perturbation method, and conditions for the formation of small but finite amplitude
dust ion-acoustic solitary waves in the space dusty plasma situations are clearly explained. It is shown that a more depletion
of the background free electrons owing to the attachment of these electrons to the surface of the dust grains during the charging
process can lead to the formation of solitary waves with smaller amplitude. Furthermore, effects of the dust charge fluctuation
and deviations from isothermality of electrons show a non-uniform behavior for the amplitude of solitary waves in transition
from the Boltzmann electron distribution to a trapped electron one. It is also found that the dust charge fluctuation caused
by trapped as well as free electrons is a source of dissipation, and is responsible for the formation of the dust ion-acoustic
shock waves. 相似文献
8.
A theoretical investigation has been made of propagating electrostatic waves in a four-component adiabatic dusty plasma, whose
constituents are adiabatic electrons, adiabatic ions, adiabatic positively and as well as negatively charged warm dust. The
basic features of the solitary structures in such a four-component adiabatic dusty plasma are studied by the reductive perturbation
method. It is found that the presence of the positive dust component does not only significantly modify the basic properties
of the solitary waves, but also causes the existence of the positive solitary potential structures, which is an interesting
feature shown in an adiabatic dusty plasma with the dust of opposite polarity. It is also observed that the basic properties
(polarity, speed, amplitude and width) of the DA SWs are significantly modified by the effects of adiabaticity (γ>1) of electrons, ions, negatively as well as positively charged warm dust. The present investigation can be of relevance
to the electrostatic solitary structures observed in various dusty space plasma environments (viz. cometary tails, upper mesosphere,
Jupiter’s magnetosphere, etc.). 相似文献
9.
H. Alinejad 《Astrophysics and Space Science》2012,337(1):223-229
A theoretical investigation is developed to study the existence, formation and basic properties of arbitrary amplitude dust
ion-acoustic solitary potentials in a dusty plasma consisting of warm ions, trapped electrons and immobile negative (positive)
dust particles. It is found a definite interval for the Mach number for which solitary waves exist and depend sensitively
on the ion temperature and negative (positive) dust concentration. In addition, the effects of ion temperature, two oppositely
charged dust species and resonant electrons on the shape of the solitary waves are also investigated extensively. For both
cases of negative and positive dust grains, the effect of ion temperature is found to be destructive for the formation of
localized structures. Further, the amplitude of the solitary structures decreases (increases) with the increase in the negative
(positive) dust concentration. 相似文献
10.
Arbitrary amplitude dust acoustic waves (DAW’s) in two high energy-tail ion distributions are investigated. The electron number
density has been assumed sufficiently depleted during the charging of the dust grains, on account of the attachment of the
background plasma electrons on the surface of the dust grains. Our results reveal that under certain conditions, DA solitary
waves with either negative or positive potential may be admitted. The high degree of suprathermalization of the relatively
low temperature ion component favors the development of compressive localized structures. This behavior is preserved to a
large extent in the small but finite amplitude regime. This means that the presence of additional relatively low temperature
suprathermal ions does not only significantly modify the basic properties of DA structures, but also causes the existence
of positive solitary potentials. This feature is completely new in a dusty plasma with two suprathermal ion components with
widely disparate temperatures. Our results may be relevant to a number of space dusty plasma systems, particularly, the Saturn’s
F-ring where electron depletion and suprathermality are thought to come into play. 相似文献
11.
The propagation of dust ion acoustic waves is studied in plasmas composed of superthermal distributed electrons and stationary dust particles. The nonlinear Schrödinger equation is derived using the reductive perturbation technique and the modulational instability of dust ion acoustic waves is analyzed. Parametric investigations indicate that the presence of superthermal distributed electrons significantly modify the modulational instability and its growth rate. The effect of particle relative density on the wave characters is also investigated. 相似文献
12.
Using the Sagdeev pseudo-potential technique, further investigation on the effect of nonextensive hot electrons on finite amplitude nonlinear low-frequency electrostatic waves in a magnetized two-component plasma have been reported in detail. The plasma model consists of cold ions fluid and nonextensively distributed electrons. The existence domain for the nonlinear structures have been established analytically and numerically. Apart from the compressive and rarefactive soliton solutions that have been reported earlier, the present investigation shows that double layer structures can be obtained for certain values of nonextensive electrons in the supersonic Mach number regime. The present results may provide an explanation for the observed nonlinear structures in the auroral region of the Earth’s magnetosphere. 相似文献
13.
N. Y. Tanisha I. Tasnim S. Sultana M. Salahuddin A. A. Mamun 《Astrophysics and Space Science》2014,353(1):137-144
Propagation of the dust-acoustic shock waves (DASWs) in a dusty plasma containing arbitrarily charged dust, positive and negative ions following nonthermal (Cairn’s) distribution, and electrons following q-(nonextensive) distribution, has been investigated. The reductive perturbation technique is used to derive the Burgers equation for dust’s fluid dynamics. The basic features (viz. polarity, amplitude, speed, etc.) of DASWs are found to be significantly modified due to the effects of arbitrarily charged dust, number density and temperatures of heavier/lighter ions, nonextensive electrons, and dust kinematic viscosity. The present investigation can be very effective for understanding the nonlinear characteristics of the DASWs in space and laboratory dusty plasmas. 相似文献
14.
The large amplitude Ion-acoustic solitons in collisionless plasma consisting of warm adiabatic ions, isothermal positrons and two-temperature distribution of electrons are investigated. Using pseudo-potential approach, an energy integral equation for the system has been derived which encompasses complete nonlinearity for the plasma system. The existence region of the solitons is analyzed numerically. It is found that for selected set of plasma parameters, both rarefactive and compressive solitons exist in the electron-positron-ion (EPI) plasma. It is also found that due to finite positron concentration both subsonic and supersonic rarefactive soliton exist in EPI plasma. An increase in finite ion temperature ratio decreases the amplitude of the rarefactive solitons. In the case of small amplitude, it is found that there exist supersonic compressive as well as rarefactive solitons simultaneously. The amplitude of the solitons decreases with increase in ion temperature ratio (σ), however an increase in positron concentration (α) and temperature ratio of positron to electrons (γ) increases the amplitude of the solitons. Effect of various plasma parameters on the characteristics of the solitons are discussed in detail. The results of the investigation may be helpful to understand the nonlinear structures in auroral plasma, pulsars and magnetospheric astrophysical environment as well as laboratory plasmas. 相似文献
15.
Small amplitude dust-acoustic solitary waves in an unmagnetized dusty plasma consisting of electrons and two temperature ions obeying the q-nonextensive distribution are investigated. Employing reductive perturbation method, the Korteweg-de Vries (KdV) equation is derived. From the solitonic solutions of KdV equation, the influence of nonextensivity of electrons as well as ions and dust concentration on the amplitude and width of dust-acoustic solitary waves has been studied. It is observed that both positive and negative potential dust acoustic solitary waves occur in this case. The modified KdV (mKdV) equation is derived in order to examine the solitonic solutions for the critical plasma parameters for which KdV theory fails. The parametric regimes for the existence of mKdV solitons and double layers (DLs) have also been determined. Positive potential double layers are found to occur in the present study. 相似文献
16.
Linear and nonlinear analysis are presented for an electronegative dusty plasma system. Linear analysis shows that the dispersive nature of the plasma system changes considerably due to the presence of nonthermal q-nonextensive distributed electrons. The presence of both compressive and rarefactive Sagdeev solitons is investigated and shown that the addition of even a small population of dust particles will significantly modify the large amplitude Sagdeev solitons. The coexistence of both compressive and rarefactive solitons for a certain set of parameters is also noticed in such system. The effect of variation of entropic index q, θ i (ratio of positive ion temperature to electron temperature), θ n (ratio of negative ion temperature to electron temperature) and dust particles concentration (R) is elaborated with the help of suitable parameters. 相似文献
17.
E. K. El-Shewy M. I. Abo el Maaty H. G. Abdelwahed M. A. Elmessary 《Astrophysics and Space Science》2011,332(1):179-186
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
18.
The nonlinear properties of solitary waves structure in a hot magnetized dusty plasma consisting of a negatively charged,
extremely massive hot dust fluid, positively charged hot ion fluid and vortex-like distributed electrons, are reported. A
modified Korteweg de Vries equation (mKdV) which admits a solitary wave solution for small but finite amplitude is derived
using a reductive perturbation theory. The modifications in the amplitude and width of the solitary wave structures due to
the inclusion of an external magnetic field and dust and ions temperature are investigated.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
The nonlinear propagation of dust acoustic (DA) waves in an unmagnetized dusty plasma system consisting of negatively charged mobile dust fluid, Boltzmann distributed electrons, and two-temperature nonthermally distributed ions, is rigorously investigated. The reductive perturbation method has been employed to derive the Burgers equation. The hydrodynamic equation for inertial dust grains has been used to derive the Burgers equation. The effects of two temperature nonthermally distributed ions and dust kinematic viscosity, which are found to significantly modify the basic features of DA shock waves, are briefly discussed. Our present investigation can be effectively utilized in many astrophysical situations (e.g. satellite or spacecraft observations, Saturn’s E ring, etc.), which are discussed briefly in this analysis. 相似文献
20.
A rigorous theoretical investigation on the characteristics of dust-ion-acoustic (DIA) shock waves in an unmagnetized multi component electron-positron-ion dusty plasma (consisting of inertial ions, electrons of two distinct temperatures referred to as low and high temperature superthermal electrons where superthermality is introduced via the κ-type of nonthermal distribution, Boltzmann distributed positrons, and negatively charged immobile dust grains) has been made both theoretically and analytically. The hydrodynamic equation for inertial ions has been used to derive the Burgers equation. The influence of superthermal electrons, Maxwellian positrons and ion kinematic viscosity, which are found in this investigation, significantly modify the basic features of DIA shock waves, are briefly discussed. The present investigation can be very effective for studying and understanding the basic characteristics of shock wave propagation through different astrophysical situations where distinct temperature superthermal electrons dominate the wave dynamics. 相似文献