The nonlinear propagation of large amplitude dust ion-acoustic (DIA) solitary waves (SWs) in an ion-beam plasma with stationary charged dusts is investigated. For typical plasma parameters relevant for experiments [J. Plasma Phys. \textbf{60}, 69 (1998)], when the beam speed is larger than the DIA speed ($v_{b0}\gtrsim1.7c_s$), three stable waves, namely the "fast" and "slow" ion-beam modes and the plasma DIA wave are shown to exist. These modes can propagate as SWs in the beam plasmas. However, in the other regime ($c_s<v_{b0}<1.7c_s$), one of the beam modes when coupled to the DIA mode may become unstable. The SWs with positive (negative) potential may exist when the difference of the nonlinear wave speed ($M$) and the beam speed is such that $1.2\lesssim M-v_{b0}\lesssim1.6$ ($M-v_{b0}\gtrsim1.6$). Furthermore, for real density perturbations, the wave potential $(>0)$ is found to be limited by a critical value which typically depends on $M$, $v_{b0}$ as well as the ion/beam temperature. The conditions for the existence of DIA solitons are obtained and their properties are analyzed numerically in terms of the system parameters. While the system supports both the compressive and rarefactive large amplitude SWs, the small amplitude solitons exist only of the compressive type. The theoretical results may be useful for observation of soliton excitations in laboratory ion-beam driven plasmas as well as in space plasmas where the charged dusts play as impurities.
Arbitrary amplitude dust acoustic solitary structures have been investigated in a four component multi-species plasma consisting of negatively charged dust grains, nonthermal ions, isothermally distributed electrons and positrons including the effect of dust temperature. We have used the Sagdeev pseudo-potential method to discuss the arbitrary amplitude steady state dust acoustic solitary structures in the present plasma system. We have designed a computational scheme to draw the existence domains of different dust acoustic solitary structures. We have observed only negative potential solitary…
The space electron-ion-positive dust plasma system containing isothermal inertialess electron species, cold inertial ion species, and stationary positive (positivively charged) dust species is considered. The basic features of one dimensional (1D) planar and nonplanar subsonic solitary waves are investigated by the pseudo-potential and reductive perturbation methods, respectively. It is observed that the presence of the positive dust species reduces the phase speed of the ion-acoustic waves, and consequently supports the subsonic solitary waves with the positive wave potential in such a space …
The dusty plasma system (containing nonthermally distributed inertialess electron species, warm inertial ion species, and positively charged stationary dust species) is considered. The basic features of subsonic and supersonic modified-ion-acoustic solitary and shock waves formed in such a dusty plasma system have been investigated by the reductive perturbation method. It has been shown that positively charged dust species play a new role in favor of the formation of subsonic solitary and shock waves. On the other hand, the ion fluid temperature (represented by the parameter $σ$) and the elect…
We report the first experimental observations of the reflection of a dust acoustic solitary wave from a potential barrier in a dusty plasma medium. The experiments have been carried out in an inverted $Π$-shaped Dusty Plasma Experimental (DPEx) device in a DC glow discharge plasma environment. The dust acoustic solitary wave is excited by modulating the plasma with a short negative Gaussian pulse that is superimposed over the discharge voltage. The solitary wave structure is seen to move towards a potential barrier, created by the sheath around a biased wire, and turn back after reflecting off…
The propagation characteristics of small-amplitude dust-acoustic (DA) solitary waves (SWs) and shocks are studied in an unmagnetized dusty plasma with a pair of trapped positive and negative ions. Using the standard reductive perturbation technique with two different scaling of stretched coordinates, the evolution equations for DA SWs and shocks are derived in the forms of complex Korteweg-de Vries (KdV) and complex Burgers' equations. The effects of dust charge variation, the dust thermal pressure, and the ratios of positive to negative ion number densities as well as the free to trapped ion …
Dust ion acoustic solitary structures in nonthermal dusty plasma
研究了由负电荷尘埃粒子、绝热正离子和非热电子组成的非磁化非热等离子体中尘埃离子声孤波结构。对于等温电子，目前的等离子体系统不支持任何双电层解决方案，而对于非热电子，负电位双电层开始出现时，非热参数超过一个临界值。然而，这种双层解并不能限制本系统所有负势孤立波的出现。结果表明，两种不同类型的负势孤波的出现受到M_c<M<M_D whereas the second type solitary wave exists for all M>_D的限制，其中M_c为马赫数M的下限，M_D（>M_c）为负势双层对应的马赫数。在M=M_D-ε_1和M=M_D+ε_2处，观察到孤波负势振幅之间的有限跳跃，其中0<ε_1<M_D-M_c和ε_2>0。提出了双电层存在的解析理论。还提供了一个数值方案，以找出存在双层解时的马赫数值以及该双层的振幅。虽然两极孤波共存的发生受到M_c<M <= M_max的限制，但当M>M_max时，仍然只存在负势孤波，这里M_max是只存在正势孤波时M的上界。发现了反映能量积分孤立子结构性质的不同组分参数空间，这些解空间为孤立子结构的形成提供了新的结果和物理思想。
The purpose of this paper is to extend the recent work of Paul & Bandyopadhyay [Astrophys. Space Sci. 361, 172(2016)] on the existence of different dust ion acoustic solitary structures in an unmagnetized collisionless dusty plasma consisting of negatively charged static dust grains, adiabatic warm ions, nonthermal electrons and isothermal positrons in a more generalized form by considering nonthermal positrons instead of isothermal positrons. The present system supports both positive and negative potential double layers, coexistence of solitary waves of both polarities and positive potential …
We investigate the propagation characteristics of two counter propagating dust acoustic solitary waves (DASWs) undergoing a head-on collision, in the presence of strong coupling between micron sized charged dust particles in a complex plasma. A coupled set of nonlinear dynamical equations describing the evolution of the two DASWs using the extended Poincaré-Lighthill-Kuo perturbation technique is derived. The nature and extent of post collision phase-shifts of these solitary waves are studied over a wide range of dusty plasma parameters in a strongly and a weakly coupled medium. We find a sign…
The nonlinear propagation of dust acoustic solitary waves (DASWs) in an unmagnetized dusty plasma consisting of negatively charged dust fluid Boltzmann distributed electrons with two different temperatures Boltzmann distributed ions with two distinct temperatures are investigated. By employing the reductive perturbation technique that is valid for a small but finite amplitude limit the Korteweg de Vries (K-dV) equation have been derived. Our results reveal that the main quantities of DASWs (such as amplitude and width) are affected by two different temperatures electrons (as well as ions) temp…
The Sagdeev pseudo-potential technique and the analytic theory developed by Das et al. [J. Plasma Phys. 78, 565 (2012)] have been used to investigate the dust ion acoustic solitary structures at the acoustic speed in a collisionless unmagnetized dusty plasma consisting of negatively charged static dust grains, adiabatic warm ions, nonthermal electrons and isothermal positrons. The present system supports both positive and negative potential solitary waves at the acoustic speed, but the system does not support the coexistence of solitary structures of opposite polarity at the acoustic speed. Th…
Sardar et al. [Phys. Plasmas 23, 073703 (2016)] have studied the stability of small amplitude dust ion acoustic solitary waves in a collisionless unmagnetized electron - positron - ion - dust plasma. They have derived a Kadomtsev Petviashvili (KP) equation to investigate the lowest - order stability of the solitary wave solution of the Korteweg-de Vries (KdV) equation for long-wavelength plane-wave transverse perturbation when the weak dependence of the spatial coordinates perpendicular to the direction of propagation of the wave is taken into account. In the present paper, we have extended th…
An investigation of dust-acoustic solitary waves in unmagnetized dusty plasma whose constituents are inertial charged dust grains, Boltzmannian electrons and nonthermal ions has been conducted. The pseudo potential as well as the reductive perturbation methods have been used in high and small amplitude limits. The existence of solitary waves of a positive as well as a negative potential is reported.
Dust-ion-acoustic damped solitary waves and shocks in laboratory and Saturn's E-ring magnetized nonthermal dusty plasmas with anisotropic ion pressure and dust-charge fluctuation
A viscous dusty plasma containing Kappa distributed electrons, positive warm viscous ions and constant negatively charged dust grains with viscosity have been considered to study the modes of dust ion acoustic waves (DIAWs) theoretically and numerically. The derivations and basic features of shock and solitary waves with different plasma parameters like Mach number, finite temperature coefficient, unperturbed dust streaming velocity, kinematic viscosity of dust etc. of this DIAWs mode have been performed. Considering the dynamical equation from Korteweg de Vries(KdV) equation, a phase portrait…
Dust-ion collisional effect in dust ion acoustic waves is investigated in the framework of spherical and cylindrical geometry. For such study the fluid equation are takes and collisional effect is consider in the equation of momentum balance. Using reductive perturbation technique the evolution equation is derived with additional damping term for non planner geometry. Using the conservation principle an analytical time dependent solitary wave solution is obtained for the evolution equation. It is seen that dust ion collisional frequency has an significant effect on the width and amplitude of t…
The amplitude modulation of three dimensional (3D) dust ion-acoustic wave (DIAW) packets is studied in a collisionless magnetized plasma with inertial positive ions, superthermal electrons and negatively charged immobile dust grains. By using the reductive perturbation technique, a 3D-nonlinear Schrödinger (NLS) equation is derived, which governs the slow modulation of DIAW packets. The latter are found to be stable in the low-frequency $(ω<ω_c)$ regime, whereas they are unstable for $ω>ω_c$, and the modulational instability (MI) is related to the modulational obliqueness $(θ)$. Here, $ω~(ω_c)…
Propagation of solitary wave in dusty plasmas started to draw the attention of the physicists since the early 90s. The presence of superthermal particles seems to have a great impact on such waves, as they indicate the existence of non-thermal systems. It has been observed that the superthermal population is capable of altering the nature of the plasmas waves. In the present paper, the effect of the superthermal electron population on the dust ion acoustic solitary wave has been explored. The plasma is considered un-magnetized and composed of two components of superthermal electrons (of two di…
Dust acoustic (DA) waves evolving into shocklets are investigated in the Comet Halley plasma system relaxing to Maxwellian, Kappa and Cairns distributions. Here dynamics of dust is described by the fully nonlinear continuity and momentum equations. A set of two characteristic wave nonlinear equations is obtained and numerically solved to examine the DA solitary pulse which develops into oscillatory shocklets with the course of time such as at time τ=0, symmetric solitary pulses are formed, which develop into oscillatory shocklets. It has been observed that variation in superthermality strongly…
A multi-species magnetized collisional nonthermal plasma system containing inertial ion species, non-inertial electron species following nonthermal $κ-$ distribution, and immobile dust particles, is considered to examine the characteristics of the dissipative dust-ion-acoustic (DIA) soliton modes, \textbf{theoretically and parametrically}. The electrostatic solitary modes are found to be associated with the low frequency dissipative dust-ion-acoustic solitary waves (DIASWs). The ion-neutral collision is taken into account, and the influence of ion-neutral collisional effects on the dynamics of…
Dust-acoustic (DA) waves (DAWs) and their modulational instability (MI) have been investigated theoretically in a plasma system consisting of inertial opposite polarity (positively and negatively) warm adiabatic charged dust particles as well as inertialess non-extensive $q$-distributed electrons and non-thermal ions. A nonlinear Schrödinger (NLS) equation is derived by using the reductive perturbation method. It has been observed from the analysis of NLS equaion that the modulationally stable solitary DAWs give rise to the existence of dark envelope solitons, and that the modulationally unsta…
Theoretical Research Institute, Pakistan Academy of Sciences (TRIPAS)（巴基斯坦科学院理论研究所）；School of Natural Sciences (SNS), National University of Sciences and Technology (NUST)（国立科学与技术大学自然科学学院）；Department of Scpace Science, Institute of Space Technology (IST)（太空技术研究院空间科学系）
The purpose of this paper is to expand the recent work of Sardar et al. [Phys. Plasmas 23, 123706 (2016)] on the existence and stability of alternative dust ion acoustic solitary wave solution of the combined modified Kadomtsev Petviashvili - Kadomtsev Petviashvili (MKP-KP) equation in a nonthermal plasma. Sardar et al. [Phys. Plasmas 23, 123706 (2016)] have derived a combined MKP-KP equation to describe the nonlinear behaviour of the dust ion acoustic wave when the coefficient of the nonlinear term of the KP equation tends to zero. Sardar et al. [Phys. Plasmas 23, 123706 (2016)] have used thi…
A complex plasma medium (containing Cairns nonthermal electron species, adiabatically warm inertial ion species, and stationary positively charged dust (PCD) species (making a plasma system very complex) is considered. The effects of PCD species, nonthermal electron species, and adiabatic ion-temperature on ion-acoustic (IA) solitary waves (SWs) and double layers (DLs) are investigated by the pseudo-potential approach, which is valid for the arbitrary amplitude time-independent SWs and DLs. It is observed that the presence of the PCD species reduces the phase speed of the IA waves, and consequ…
We report on experimental observations on the modifications in the propagation characteristics of precursor solitons due to the different shapes and sizes of the object over which the dust fluid flows. The experiments have been performed in a $Π$ shaped Dusty Plasma Experimental (DPEx) device where dusty plasma is created in a DC glow discharge Ar plasma using kaolin particles. A floating copper wire installed radially on the cathode, acts as a charged object in the plasma environment. The flow on the dust fluid is initiated by suddenly lowering the potential of the charged object from grounde…
