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.
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…
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 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…
Higher order stability of dust ion acoustic solitary wave solution described by the KP equation in a collisionless unmagnetized nonthermal plasma in presence of isothermal positrons
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…
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…
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)
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…
Effect of size and shape of a moving charged object on the propagation characteristics of precursor solitons
我们报告的实验观测的修改的前体孤子的传播特性,由于不同的形状和大小的对象,尘埃流体的流动。实验已经在$Π$形状的尘埃等离子体实验(DPEx)装置中进行,其中尘埃等离子体在DC辉光放电Ar等离子体中使用高岭土颗粒产生。在阴极上径向安装的浮动铜线在等离子体环境中充当带电物体。粉尘流体上的流动是通过将带电物体的电位从接地电位突然降低到接近浮动电位而启动的。电位山的大小(高度和宽度)通过一个可变电阻从导线中引出电流而改变。随着势峰高度的减小,孤子的振幅、速度和数目减小,而孤子的宽度增大.结果发现,低于阈值,这些孤立波不激发和尘埃流体简单地流过山。为了检查由于电势分布的形状引起的效果,用三角形物体代替导线。只有拖尾尾流被认为是激发时,尘埃流体面临的线性增加的斜率的潜在的配置文件,而孤立子和唤醒得到激发时,对象被放置与尖锐的边缘面对流。所有的实验结果定性同意与不同的源项在强迫Korteweg de Vries(f-KdV)模型方程的数值解。