Landau damping of longitudinal oscillation in ultra- relativistic plasmas with nonextensive distribution

The generalized dispersion equation for longitudinal oscillation in an unmagnetized, collisionless, isotropic and relativistic plasma is derived in the context of nonextensive q-distribution. An analytical expression for the Landau damping is obtained in an ultra-relativistic regime, which is related to q-parameter. In the limit q → 1, the result based on the relativistic Maxwellian distribution is recovered. It is shown that the interactions between the wave and particles are stronger and the waves are more strongly damped for lower values of q-parameter. The results are explained by the increased number of superthermal particles or low velocity particles contained in the plasma with the nonextensive distribution.     

Dispersion relation for longitudinal waves in a relativistic plasmas

Imre, Buti and others studied the longitudinal waves from the general dispersion relation. Here we have derived the dispersion relation for the longitudinal waves in relativistic plasmas, a result which cannot easily be brought in a physically more convenient form.     

平面火花隙三电极开关研制及性能测试

研制了一种适用于平行板传输连接的平面火花隙三电极开关，开关正负电极为半圆形状，触发电极为细条状。将之替代立体式（半球形电极）火花隙三电极开关并应用于爆炸箔起爆装置中，装置回路参数将得以优化。实验测试了空气间隙为4.12， 3.14和2.2 mm的平面火花隙三电极开关的性能。结果表明，在开关间隙间距一定的情况下，随着电压的升高，开关间隙的放电时延和分散时间呈指数降低，开关电感小于15 nH；对于不同范围内的应用电压，使用不同间隙间距的开关，其分散时间不大于10 ns。该开关应用于较低充电电压（小于10 kV）的脉冲功率装置中，与立体式火花隙三电极开关相比，回路电感降低了约50 nH，放电周期缩短近1/3，峰值电流增加约1/3。     

相对论q分布正负电子对等离子体横振荡

研究了无磁化、无碰撞、各向同性相对论q分布正负电子对等离子体横振荡色散关系,通过理论推导得到与非广延参数q有关的色散方程。从该色散方程出发,得到极端相对论情况下长波支和短波支下等离子体横振荡色散关系解析解,为了得到完整的色散曲线,对色散方程进行数值计算,在极端相对论情况下数值结果与解析结果在长波支和短波支下完全吻合。研究发现相对论q分布下色散关系与非广延参数q和温度有关,当q1时,则渐进结果与经典统计下的一致。     

费米分布相对论等离子体的色散关系

将Mikhailovskii 色散关系的理论用于费米分布的等离子体中,分别对纵振荡和横振荡进行数值模拟。结果表明,该方法得到的色散关系在极端相对论条件下不仅与Mikhailovskii 的理论相吻合,还得到了Mikhailovskii 没有涉及的范围内的色散关系。模拟得到了费米分布等离子体不同温度下纵振荡和横振荡的色散关系。     

Landau damping of dust acoustic waves in the plasma with nonextensive distribution

The Landau damping of dust acoustic waves propagating in a dusty plasma composed of nonextensive distributed electrons and ions, and Maxwellian distributed dust grains is investigated based on kinetic theory. The dust acoustic waves are found in the range of k_vd?ω?k_vi?k_ve$k{v}_d?\omega ?k{v}_i?k{v}_e$, where _vα$v_{\alpha }$ is the thermal velocity of species α(=i,e,d)$\alpha (=i,e,d)$. The damping rate is shown to be dependent on the nonextensivity parameter q$q$ as well as the ratio of ion density to electron. In the limit q→1$q\to 1$, the result based on the Maxwellian distribution is recovered. The maximum Landau damping rate is found to be enhanced as the population of the electron density decreases.     

Charging of a dust particle in a plasma with a nonextensive ion distribution function

The dust charge neutralization in a plasma with nonextensive ions is considered. The condition that the total current to a grain be zero is expressed in terms of the Lambert function. The fall-off of the net negative dust charge is then considered and a parameter study conducted, assuming hydrogen as well as argon plasma. Owing to ion nonextensivity, the dust charge reduction becomes much faster. Moreover, stronger is the ions correlation, more important is the involved electron depletion for a complete dust “decharging”.     

An equilibrium thermostatistics of a nonextensive finite system: Canonical distribution and entropy

A simple model is presented to illustrate the equilibrium thermostatistics of a nonentensive finite system. Interaction between the finite system and the reservoir is taken into account as a nonextensive term λ_H1H2$\lambda H_1{H}_2$ in the expression of total energy (_H1$H_1$ and _H2$H_2$ are the energy of the finite system and the reservoir respectively, λ$\lambda$ is nonadditivity parameter). In the present paper, a case with harmonic reservoir potential is considered. Energy probability distribution, average energy, heat capacity and entropy function for energy distribution are derived in different finite systems including those with constant density of state in energy, the ideal gas and the phonon gas.     

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导出了无磁化无碰撞各向同性相对论正负电子对等离子体纵波的色散关系。使用逐次近似的标准技术,对两种极限情况下的纵波色散方程进行了解析研究。将完全色散方程进行变换,使它们完全适用于在需要完全相对论处理的温度范围内进行数值计算。用数值模拟方法得到了用解析方法不能得到的完全的色散曲线。     

Dressed ion acoustic solitary waves in quantum plasmas with two polarity ions and relativistic electron beams

A theory for dressed quantum ion acoustic waves (QIAWs), which includes higher-order corrections when QIAWs are investigated by the reductive perturbation method, is presented for unmagnetized plasmas containing positive and negative ions and weakly relativistic electron beams. The properties of the QIAWs are investigated using a quantum hydrodynamic model, from which a Korteweg–de Vries equation is derived using the reductive perturbation method. An equation including higher-order dispersion and nonlinearity corrections is also derived, and the physical parameter space is discussed for the importance of these corrections.     

一种柱-锥盘荷波导的色散关系

 导出了柱-锥盘荷波导的色散方程，并通过数值计算分析了这种慢波结构的几何参数对相对论行波管运行频率和通带的影响，与柱形盘荷波导相比，这种慢波结构的上截止频率高于柱形盘荷波导,因此，可以得到较高的运行频率和较大的通带,为设计这种慢波器件提供了依据。     

具有非广延分布电子的碰撞等离子体磁鞘的结构

很多关于等离子体鞘层的研究工作都是基于电子满足经典的麦克斯韦速度分布函数,而等离子体中的粒子具有长程电磁相互作用,使用Tsallis提出的非广延分布来描述电子更为恰当.本文建立一个具有非广延分布电子的碰撞等离子体磁鞘模型,理论推导出受非广延参数q影响的玻姆判据,离子马赫数的下限数值会随着参数q的增大而减小.经过数值模拟,发现与具有麦克斯韦分布(q=1)电子的碰撞等离子体磁鞘对比,具有超广延分布(q<1)和亚广延分布(q>1)电子的碰撞等离子体磁鞘的结构各有不同,包括空间电势分布、离子电子密度分布、空间电荷密度分布.模拟结果显示非广延分布的参数q对碰撞等离子体磁鞘的结构具有不可忽略的影响.希望这些结论对相关的天体物理、等离子体边界问题的研究有参考价值.     

Dispersion relation of dust acoustic wave in multi-wall fullerene studied by the quantum hydrodynamic model

In this letter, dispersion properties of low-frequency electrostatic waves in multi-wall fullerene (the first layer is C₆₀molecule) are investigated. It is assumed that multi-wall fullerene is charged due to the field emission, and hence the multi-wall fullerene can be regarded as charged dust spheres surrounded by degenerate electrons and ions. We obtain the dispersion relation for the low-frequency electrostatic oscillations in the multi-wall fullerene by using the quantum hydrodynamic model in conjunction with the Poisson equation.     

双离子成份等离子体的离子声色散关系

以离子温度与电子温度之比为参数,将等离子体介电函数作展开,由此解析地求解了双离子成分等离子体的离子声快、慢波模的色散关系。与现有的其它解析理论相比较,所得到的解析公式更加准确。     

Electrostatic solitary waves associated with relativistic nonextensive electrons in magnetized fusion plasma

Properties of nonlinear electrostatic solitary waves in a magnetized multicomponent system of plasma containing of warm fluid ions, weakly relativistic warm fluid electrons and q-nonextensive distributed electrons using reductive perturbation method, have been surveyed. For this purpose, a KdV soliton type solution has been employed. The dependence of solitary wave structure, solitary wave maximum amplitude, and phase velocity of soliton on the plasma parameters is defined numerically.     

超声速气流中液体横向射流的非定常特性与振荡边界模型

针对液体圆柱射流垂直喷入超声速横向气流中的非定常分布特性开展实验研究, 并建立穿透深度方向上的射流振荡分布模型. 利用脉冲激光背景成像方法“冻结”拍摄马赫2.1(Ma=2.1)气流中煤油射流/喷雾瞬态图像, 结合最大类间方差法(Otsu)和Canny算法提取瞬态图像特征, 基于统计方法并引入间歇因子(γ)定量描述射流振荡分布特性; 通过研究多参数协同作用下的射流振荡分布规律, 提出振荡分布数学模型, 研究的参数变量包括超声速来流总压(642-1010 kPa)、 液体喷注压降(0.36-4.61 MPa)、液体喷嘴流道直径 (0.48 mm/1.0 mm/1.25 mm/1.52 mm)、距离喷嘴的流向距离(10-125 mm)以及液气动量通量比(0.11-7.49). 研究中利用射流振荡分布模型成功预测出水射流在Ma=2.1气流中的的振荡分布, 预测分布与实验结果符合良好.     

量子等离子体中波的色散关系以及朗道阻尼

利用动理学理论研究量子等离子体中波的色散关系和电子朗道阻尼.从电子的量子流体动力学方程和动理学描述下的光子运动方程出发,研究量子效应对光子朗道阻尼的修正.研究发现量子效应只对纵波模式,即电子等离子体波的色散关系有修正,对横向电磁波的色散关系没有影响.量子效应减小了朗道阻尼,起着朗道增长的作用. 关键词： 量子等离子体 朗道阻尼 电子等离子体波 色散关系     

Calculation of energy density in the colour tube model of relativistic heavy ion collisions

The energy density produced in a relativistic heavy ion collision is calculated within the framework of the colour tube model. The chromoelectric field generated in the collision produces quark-antiquark pairs. The motion of these particles is described by Boltzmann equation. The interaction between the quarks and antiquarks is approximated by introducing a relaxation time.     

Analysis and Calculations on Dispersion Relation and Coupling Resistance of Periodic Plasma-Cavities

The plasma tensor dielectric permittivity and electromagnetic field accurate expressions in the external axial magnetic field are obtained from the Maxwell’s equations and the double component plasma particle linear movement equations. Further, the flux of energy inside the plasma-cavity drift channel is presented. Based on them, some of the property of cavity passband dispersion and coupling resistance of plasma-filled coupled-cavities slow wave structure in different plasma density and magnetic field conditions is analyzed according to the numerical calculation.     

双麦克斯韦分布尘埃等离子体中尘埃粒子的充电研究

根据充电方程和电荷守恒条件,导出了双麦克斯韦分布的弱电离尘埃等离子体充电频率(电荷弛豫速率),给出了充电电流的计算公式. 对结果分析表明,定向运动速度大小对充电电流和充电频率有一定的影响,充电频率随着定向速度增加而减小,当定向速度远远小于电子的热速度时,充电频率与文献给出的表达式一致. 关键词： 尘埃等离子体 双麦克斯韦分布 充电频率