尘埃等离子体中非线性波的叠加效应及稳定性问题

研究了小的有限振幅的无磁场尘埃等离子体中的非线性波.在一维情况下由Kortewegde Veries(KdV)方程来描述,考虑了二维情况下尘埃等离子体中尘埃颗粒上电荷的变化效应以及双温度离子效应后,尘埃等离子体受到横向高阶扰动后动力学方程由Kadomtsev-Petviashvili(KP)方程来描述.在此基础上,研究了以任意夹角传播的两个及三个孤立子的相互作用问题,考虑非线性效应后振幅相等的双孤立子在相互作用区域内振幅最大值是单个孤立子振幅的4倍,振幅相等的三孤立子在相互作用区域内振幅最大值是单个孤立子振幅的9倍.研究还表明波的传播方向受到横向高阶扰动后是稳定的.     

强碰撞磁化尘埃等离子体中的漂移波

研究磁化尘埃等离子体的波动机理,对相关实验、工业加工、天体空间探测等具有重要的价值.本文研究了非均匀磁化尘埃等离子体系统的线性和非线性波动特性.对处于均匀外磁场中的非均匀尘埃等离子体系统,存在密度和温度梯度的非均匀环境,考虑尘埃和中性粒子的强碰撞作用,得到了一个二维非线性磁流体动力学方程.通过线性化得到了色散关系,系统既有强碰撞引起的阻尼波,又有粒子漂移产生的谐波;典型的数值参量分析结果表明,量子参量修改了系统的尺度;实频与漂移频率成正比关系,而虚频与尘埃和中子间的碰撞频率有着比较复杂的关系,粒子的碰撞引起了系统的耗散效应.通过函数变换法,获得了漂移的冲击波和爆炸波的解析解.详细讨论了静电势随着主要物理量的变化,研究结果显示,静电冲击波的幅度和爆炸波的宽度都随尘埃密度和外界磁场强度的增大而增大,随着碰撞频率的增大而减小,随漂移速度而变化.当时空相位较小时,静电势变化很快,一旦足够大时,静电势将趋于稳定值,最终达到稳定的状态.最后对系统的稳定性问题进行了分析,发现尘埃电荷量、量子参量、漂移速度都出现在扰动解中.本文所得结果表明,强碰撞效应、量子效应、粒子漂移和外界磁场等主要物理量都对尘埃...     

尘埃等离子体

尘埃等离子体物理是近十年里等离子体学科中一个活跃的分支领域之一,带电尘埃广泛存在于空间等离子体、实验室聚变装置、低温等离子体工业应用等众多不同的环境中,并且呈现出相同或相似的性质.这是一种部分或完全电离的等离子体,其基本成分除了电子和离子外,还有(通常)带负电的、且电荷不是常数的微粒.带电颗粒有着与电子和离子完全不同的动力学行为,其与等离子体的相互作用呈现出许多新的物理现象.文章介绍了尘埃等离子体物理的简要发展历史、基本性质和主要研究方向以及最近一些热点问题.     

尘埃等离子体

尘埃等离子体物理是近十年里等离子体学科中一个活跃的分支领域之一，带电尘埃广泛存在于空间等离子体、实验室聚变装置、低温等离子体工业应用等众多小同的环境中，并且呈现出相同或相似的性质．这是一种部分或完全电离的等离子体，其基本成分除了电子和离子外，还有（通常）带负电的、且电荷不是常数的微粒．带电颗粒有着与电予和离子完全不同的动力学行为，其与等离子体的相互作用呈现出许多新的物理现象．文章介绍了尘埃等离子体物理的简要发展历史、基本性质和主要研究方向以及最近一些热点问题．     

低β尘埃等离子体中尘埃-动力学阿尔文孤立波

用三成分的流体模型,研究了尘埃等离子体中的尘埃－动力阿尔文波。导出了描述离子密度变化的非线性的能量积分方程。在小振幅极限下,得到密度的孤立子解,对Ｓａｇｄｅｅｖ势进行了数值研究。结果表明,在不同的参数区域,可以激发具有密度坑或密度隆起的孤立波;随着尘埃密度的增加,密度坑变浅,密度隆起增大。     

尘埃粒子充放电过程对尘埃等离子体电导率的影响

在只受弱电磁场作用且忽略空间色散的情况下，通过求解含碰撞项的电子的Boltzmann方程及尘埃粒子充放电的Shukla方程，导出了弱电离尘埃等离子体的电导率和介电常数计算公式. 将固体火箭喷焰的有关参数代入公式对电导率进行定量分析，结果表明，尘埃粒子的大小及其浓度对弱电离尘埃等离子体的电导率有明显的影响. 关键词： 尘埃等离子体 Boltzmann方程 Shukla方程 电导率     

尘埃等离子体中朗缪尔波的非线性调制

研究了尘埃等离子体中尘埃声波（ＤＡＷ）和尘埃离子声波（ＤＩＡＷ）对朗缪尔波的非线性调制。在小而有限振幅极限下,得到了朗缪尔波的包络孤立子。对于朗缪尔波与尘埃声波的非线性耦合,包络孤立子存在两个速度传播区;而对于与尘埃离子声波的耦合,只有一个传播区     

量子尘埃等离子体中尘埃充电对尘埃声波的影响

采用流体动力学方程组和尘埃充电方程组成的自洽模型系统,对量子尘埃等离子体中的尘埃声波波动性质进行了研究。通过线性理论分析方法得到系统的尘埃声波波动方程及其色散关系,并对色散关系进行了数值分析。研究表明:充电效应定性地修正了尘埃声波的色散特性,引起尘埃声波的耗散,其耗散强度主要与尘埃等离子体的参数有关。最后,分析了引起尘埃声波耗散的物理原因。     

量子尘埃等离子体中尘埃充电对尘埃声波的影响

采用流体动力学方程组和尘埃充电方程组成的自洽模型系统,对量子尘埃等离子体中的尘埃声波波动性质进行了研究。通过线性理论分析方法得到系统的尘埃声波波动方程及其色散关系,并对色散关系进行了数值分析。研究表明：充电效应定性地修正了尘埃声波的色散特性,引起尘埃声波的耗散,其耗散强度主要与尘埃等离子体的参数有关。最后,分析了引起尘埃声波耗散的物理原因。     

聚变等离子体中尘埃杂质的带电和运动特性及温度变化研究

研究了在磁约束聚变环境中不同等离子体参数下尘埃粒子的带电、运动及温度特性.研究表明:电子温度与离子温度比对尘埃带电量有明显的影响;二次电子发射会显著减少尘埃带电量;尘埃充电的弛豫时间比在实验室加工等离子中要短得多.在考虑离子拖曳力作用下,尘埃粒子的速度可达102m·s-1的量级;针对碳材料计算得到粒子的寿命达毫秒量级.这些数值研究结果与实验观测结果相一致.     

Experimental study of nonlinear dust acoustic solitary waves in a dusty plasma

The excitation and propagation of finite-amplitude low-frequency solitary waves are investigated in an argon plasma impregnated with kaolin dust particles. A nonlinear longitudinal dust acoustic solitary wave is excited by pulse modulating the discharge voltage with a negative potential. It is found that the velocity of the solitary wave increases and the width decreases with the increase of the modulating voltage, but the product of the solitary wave amplitude and the square of the width remains nearly constant. The experimental findings are compared with analytic soliton solutions of a model Korteveg-de Vries equation.     

一类非线性尘埃等离子体孤波解

研究了一类非线性尘埃等离子体孤波解. 首先构造一个变分迭代, 其次决定系统的初始近似, 最后通过变分迭代方法得到了对应模型的各次近似解. 关键词： 等离子体 变分迭代 近似解     

Nonlinear interaction phenomenon of dust acoustic solitary and shock waves in dusty plasma

The effects of head-on collision on dust acoustic (DA) solitary and shock waves in dusty plasma are investigated considering positively charged inertial dust, Boltzmann distributed negatively charged heavy ions, positively charged light ions, and superthermal electrons in the plasma system. The nonlinear Korteweg-de-Vries (KdV) Burger equations are derived taking the extended Poincaré-Lighthill-Kuo method into account to study the characteristic properties of nonlinearity and production of solitary shock due to collisions. The study reveals that the amplitudes and widths of the DA shock waves are decreasing with increasing viscosity, electron to dust density ratio, and dust to ion temperature ratio, while they are increasing due to the presence of superthermal electrons. The nonlinearity of DA waves are enhanced with increasing density ratio of electron to dust and temperature ratio of dust to ion and electron, respectively, but it is reducing with superthermal electrons. The phase shifts of DA solitary waves are found to decrease with rising superthermality of electrons and increase with the density ratio of electron to dust.     

Dust-acoustic solitary waves in an adiabatic hot dusty plasma

An adiabatic hot dusty plasma (containing non-inertial adiabatic electron and ion fluids, and negatively charged inertial adiabatic dust fluid) is considered. The basic properties of arbitrary amplitude dust-acoustic (DA) solitary waves, which exist in such an adiabatic hot dusty plasma, are explicitly examined by the pseudo-potential approach. To compare the basic properties (critical Mach number, amplitude and width) of the DA solitary waves observed in a dusty plasma containing adiabatic electron, ion and dust fluids with those observed in a dusty plasma containing isothermal electron and ion fluids and adiabatic dust fluid, it has been found that the adiabatic effect of inertia-less electron and ion fluids has significantly modified the basic properties of the DA solitary waves, and that on the basic properties of the DA solitary waves, the adiabatic effect of electron and ion fluids is much more significant than that of the dust fluid.     

Dust ion-acoustic solitary waves in a hot adiabatic magnetized dusty plasma

The basic features of obliquely propagating dust ion-acoustic (DIA) solitary waves in a hot adiabatic magnetized dusty plasma (containing adiabatic inertia-less electrons, adiabatic inertial ions, and negatively charged static dust) have been investigated. The reductive perturbation method has been employed to derive the Korteweg-de Vries (KdV) equation which admits a small amplitude solitary wave solution. The combined effects of plasma particle (electron and ion) adiabaticity, ion-dust collision, and external magnetic field (obliqueness), which are found to significantly modify the basic features of the small but finite-amplitude DIA solitary waves are explicitly examined. The implications of our results in space and laboratory dusty plasmas are briefly discussed.     

Dust-acoustic solitary waves in a dusty plasma with two-temperature nonthermal ions

By using reductive perturbation method, the nonlinear propagation of dust-acoustic waves in a dusty plasma (containing a negatively charged dust fluid, Boltzmann distributed electrons and two-temperature nonthermal ions) is investigated. The effects of two-temperature nonthermal ions on the basic properties of small but finite amplitude nonlinear dust-acoustic waves are examined. It is found that two-temperature nonthermal ions affect the basic properties of the dust-acoustic solitary waves. It is also observed that only compressive solitary waves exist in this system.     

Higher-order solution for dust acoustic solitary waves in an unmagnetized dusty plasma

The effect of higher-order nonlinearity on dust acoustic solitary waves is studied taking into account the dust-charge variation. The model of charge fluctuation, taken here, is of the formI _e+I _i=0,I _e andI _i being the electronic and ionic currents. The dust charge is determined self consistently from the current-balance equation. It is found that the higher-order correction modifies the amplitude and width of the dust acoustic solitary waves. The effect of dust-charge streaming is also discussed.     

Fully nonlinear ion-acoustic solitary waves in a magnetized plasma

The propagation of fully nonlinear ion-acoustic solitary waves in a magnetized plasma with cold ions and warm electrons is studied analytically. Necessary conditions for the existence of solitary waves in such a plasma were obtained by Yuet al. In this paper necessary and sufficient conditions are found.