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研究了强耦合尘埃等离子体的尘埃声波的线性色散关系和尘埃声孤波的非线性传播。考虑一个包含电子、离子、正电扰动尘埃颗粒的完全电离的三成分模型等离子体。假定其电子、离子数密度服从玻尔兹曼分布,而大质量的尘埃成分用一组经典流体方程描述,对系统方程进行线性化,得到了尘埃声波的线性色散关系,发现离子的集中参数对色散关系的影响很大。用约化摄动法对系统方程进行展开,得到了描述小振幅孤波的伯格斯方程。基于伯格斯方程研究了尘埃声孤波的基本特性,发现尘埃颗粒的强耦合效应对尘埃声孤波有很大的修正作用。该研究结果有助于理解尘埃空间等离子体中局域波的一些特性。     

强耦合尘埃等离子体中正电扰动下的尘埃声激波

研究了强耦合尘埃等离子体的尘埃声波的线性色散关系和尘埃声孤波的非线性传播。考虑一个包含电子、离子、正电扰动尘埃颗粒的完全电离的三成分模型等离子体。假定其电子、离子数密度服从玻尔兹曼分布,而大质量的尘埃成分用一组经典流体方程描述,对系统方程进行线性化,得到了尘埃声波的线性色散关系,发现离子的集中参数对色散关系的影响很大。用约化摄动法对系统方程进行展开,得到了描述小振幅孤波的伯格斯方程。基于伯格斯方程研究了尘埃声孤波的基本特性,发现尘埃颗粒的强耦合效应对尘埃声孤波有很大的修正作用。该研究结果有助于理解尘埃空间等离子体中局域波的一些特性。     

Effect of external magnetic field on nonlinear propagation of cylindrical magnetoacoustic soliton waves in quantum plasma

The propagation of magnetoacoustic solitary waves is investigated in magnetized quantum plasma consisting of cold ions and hot electrons. By using the quantum magnetohydrodynamic (QMHD) model, the nonlinear characteristics of different features of solitary waves in an electron-ion quantum magnetoplasma are investigated. Magnetoacoustic solitary waves are stationary solutions of the equations composed of the nonlinear mass and momentum continuity, together with the Maxwell's equations. The important quantum-mechanical effects including the quantum statistical and diffraction are examined numerically on the profiles of the solitons. It is found that the non-dimensional characteristic of the quantum parameter plays a significant role in the formation of the solitons.     

Statistics of magnetic field fluctuations in a partially ionized space plasma

Voyager 1 and 2 data reveals that magnetic field fluctuations are compressive and exhibit a Gaussian distribution in the compressed heliosheath plasma, whereas they follow a lognormal distribution in a nearly incompressible supersonic solar wind plasma. To describe the evolution of magnetic field, we develop a nonlinear simulation model of a partially ionized plasma based on two-dimensional time-dependent multifluid model. Our model self-consistently describes solar wind plasma ions, electrons, neutrals and pickup ions. It is found from our simulations that the magnetic field evolution is governed by mode conversion process that leads to the suppression of vortical modes, whereas the compressive modes are amplified. An implication of the mode conversion process is to quench the Alfvénic interactions associated with the vortical motions. Consequently anisotropic cascades are reduced. This is accompanied by the amplification of compressional modes that tend to isotropize the plasma fluctuations and lead to a Gaussian distribution of the magnetic field.     

Fast wave heating in a mirror during plasma build-up

A heating method for partially ionized plasma has been described in reference [V.E. Moiseenko, Sov. J. Plasma Phys. 12, 427 (1986)]. It exploits the collisional damping of fast waves that is large owing to the high rate of charge exchange collisions. Since the time of heating is limited by the duration of neutral gas ionization, the heating needs to be strong enough to achieve a high final ion temperature. This heating method has been studied numerically in the framework of MHD-like (magneto-hydrodynamic) equations in inhomogeneous cylindrical plasma. The influences of the ratio of the mean free path of the neutral atoms to the plasma radius, the initial ion concentration, the characteristics of the interaction of the neutral atoms with the chamber wall and other parameters on the plasma heating dynamics are examined. A scenario for RF plasma heating in one central cell of the multi-mirror device GOL3 (Novosibirsk, Russia) is developed, in which the final ion temperature exceeds the ion oscillation energy in the RF field by one order of magnitude. The energy efficiency is high; only a small portion of the power is transferred by the neutral atoms to the chamber wall.     

部分离化激光等离子体的受激喇曼散射不稳定性

由于部分离化激光等离子体中存在束缚电子，它可显著改变其参量不稳定性。本文分析了部分离化激光等离子体的受激喇曼散射的非线性色散关系，计算了钕玻璃倍频和三倍频激光受激喇曼散射的增长率，结果表明，前向受激喇曼散射显著增强，后向受激喇曼散射影响不大。     

Ion extraction and charge exchange in laser isotope separation

In the atomic vapor laser isotope separation (AVLIS) process, a vapor is ionized by pulsed laser beams, and the ions are extracted by negatively biased collectors. We compute the unsteady dynamics of the photoplasma using a two-dimensional (2-D) particle-in-cell (PIC) code. Collisions between ions and neutral species are simulated by a Monte Carlo technique. The plasma dynamics is visualized by snapshots of particle positions showing the directions of their velocities. The three kinds of particles (electrons, photo-ions, and ions created by charge exchange) are marked by different colors. The graphic outputs illustrate the motion of the electrons toward the anodes, the vertical drift of the plasma, its erosion by the transient ion sheath, and nonselective ionization by charge exchange     

Magnetosonic Shocks in Ultra-Relativistic Dissipative Degenerate Plasmas

Magnetosonic shock structures in dissipative magnetized degenerate electron ion plasma are studied.The two fluid quantum magnetohydrodynamic equations for non-degenerate ions and ultra-relativistic degenerate electron fluids with the Maxwell equations are presented.Using the reductive perturbation technique the Korteweg de Vries Burgers(KdVB)equation is derived and its solution is presented with the tanh method.Astrophysical plasma parameters are used to study the effects of variation of plasma density,magnetic held intensity and kinematic viscosity on the propagation characteristics of nonlinear shock structures in such plasma systems.     

Parametric Study of Nonplanar Dust Acoustic Solitons in Two‐Dimensional Superthermal Dusty Plasmas

The nonlinear properties of two dimensional low‐frequency electrostatic excitations of charged dust particles (or defects) are studied in a collisionless, unmagnetized dusty plasma. A fully ionized three‐component model plasma consisting of kappa distributed electrons, Maxwellian ions, and negatively charged massive dust grains is considered. In this regard, the well known reductive perturbation technique is used to the hydrodynamical equations and the Poisson equation, obtaining the cylindrical Kadomtsev–Petviashvili (CKP) equation. A parametric investigation indicates that the structural characteristics of these nonlinear excitations (width, amplitude) are significantly affected by the plasma nonthermality as well as by the relevant plasma parameters, such as dust concentration and dust temperature. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The nature and properties of a plasma

We have good reason to believe that much if not most of the matter in the universe is in the plasma state. This state can be described by comparing it with that of an ordinary gas, which is familiar to all of us, where large numbers of molecules move in all directions with different velocities along criss-cross paths, each sudden change of direction of movement being caused by a collision between two or more particles. But whereas in a gas all particles are electrically neutral, in a plasma charged fragments of formerly neutral molecules, positive and sometimes negative ions and electrons, take part in the random motion together with their neutral companions as well as with light quanta (von Engel 1955). In the gas of many stars, the sun, and certain apparatus in our terrestrial laboratories, charged particles predominate over neutral particles; these conditions approach a state called the fully ionized plasma (Spitzer 1956).     

Mobility of two-dimensional electrons upon scattering by a correlated distribution of impurity ions

Correlation effects in the mobility of two-dimensional electrons upon scattering by a correlated distribution of impurity ions are described in the framework of the hard-sphere model. The theory is developed for the case of partially ionized impurity centers when correlations in the distribution of impurity ions are weakened as the result of a deficit of free positions for impurity holes. The calculations are performed for heterostructures with a wide spacer when small-angle scattering of electrons dominates.     

Dispersion relations of dissipative drift waves in moderately ionized magnetoplasmas

Based on a three-fluid plasma model a theory is developed in which all collisions between electrons, ions, and neutral particles are effective. The numerical analysis satisfactorily explains an m = 4 mode instability observed in an rf generated, moderately ionized magnetoplasma.     

Nonlinear dynamics of surface dust vortex and dust zonal flow systems

We present analytical and simulation studies of highly resolved dust fluid flows involving nonlinearly coupled incompressible surface dust vortex modes (SDVMs) and dust zonal flows (DZFs) in nonuniform unmagnetized dusty plasmas. For this purpose, we use the hydrodynamic equations for the dust fluid and Boltzmann distributed electrons and ions and obtain a set of equations that exhibit nonlinear couplings between the SDVMs and DZFs. The nonlinear equations are then used to investigate the parametric excitation of DZFs by the Reynolds stresses of the SDVMs. Large scale SDVMs emerge through nonlinear interactions with DZFs, and they suppress the dust particle transport across the density gradient. In contrast, DZFs possess short scale vortices with a higher turbulent transport. The relevance of our investigation into the role of coherent structures in a nonuniform dusty plasma is discussed.     

强激光等离子体耦合效应的数值模拟

 研究了高强度（10¹²(10^{14W/cm2）,纳秒脉冲(高斯型)激光与AI、 CH等离子体的耦合效应。采用一维双温、单流体力学方程组,数值模拟研究激光强度和波长对靶表面能量沉积和对等离子体特征参数的影响。激光等离子体耦合的主要机制有:轫致辐射、逆轫致辐射吸收、热扩散和电子、离子之间碰撞能量交换。给出了电子最高温度与光强的近似定量关系。}     

The Impact of Direct Ionization by Beam Electrons on the Electron Kinetics of the Beam Discharge Plasma in Molecular Hydrogen

In a recent paper the stationary beam plasma discharge in partially dissociated hydrogen was investigated where the electron component was described by the Boltzmann equation for a mixture of atomic and molecular hydrogen and the main heavy charged and neutral particles by balance equations. It was assumed that, via the quasilinear beam plasma interaction, the electron beam produces only the turbulent electric field whilst an additional production of plasma electrons due to direct ionization by the beam and thus a direct influence on the balances of charge carriers were neglected. Now the additional production of plasma electrons due to direct ionization by the beam is studied on the basis of a generalized Boltzmann equation but for the simpler model of a purely molecular hydrogen plasma. For experimentally obtainable values of the turbulence energy density, beam energy, beam ionization degree and electron life time the calculation of the electron energy distribution function and of the direct beam contribution to the electron particle balance shows a marked influence of the direct beam ionization with increasing degree of beam ionization.     

Dissipation of energy of low-frequency waves in a weakly ionized gas

The properties of low-frequency waves in a slightly ionized gas are discussed on the basis of the Boltzmann transport and Maxwell equations. Special attention is paid to decay mechanisms forcing the gas to thermal equilibrium. It is shown that the collisional exchange of energy between ions and neutral atoms may considerably influence the dispersion equations of several modes of oscillations.The author wishes to thank Mrs. E. Dosoudilová for executing the numerical computations.     

Ionization Potential Depression in Hot Dense Plasmas Through a Pure Classical Model

The ionization potential of an ion embedded in a plasma, lowered due to the whole of the charged particles (ions and electrons) interacting with this ion, is the so‐called plasma effect. A numerical plasma model based on classical molecular dynamics has been developed recently. It is capable to describe a neutral plasma at equilibrium involving ions of various charge states of the same atom together with electrons. This code is used here to investigate the ionization potential depression (IPD). The study of the IPD is illustrated and discussed for aluminum plasmas at mid and solid density and electron temperatures varying from 50eV to 190eV. The method relies on a sampling of the total potential energy of the electron located at an ion being ionized. The potential energy of such electron results from all of the interacting charged particles interacting with it. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Theoretical model for the effect of dust grains on self‐filamentation of a gaussian electromagnetic beam in a fully ionized plasma

A theoretical model for the effect of dust grains on the self‐filamentation of a Gaussian electromagnetic beam propagating in a fully ionized plasma has been developed by employing the energy balance of the plasma constituents, perturbed electron and ion concentrations, and temperature. In this model, neutral atom ionization, re‐integration and accumulation of electrons and ions, photoelectric emission of electrons from the surface of dust grains, as well as elastic and charging collisions have also been considered. The effective dielectric constant in the presence of dust grains has been constructed. The effect of temporal growth of dust grains on various plasma parameters for different values of the dust density has been explored. The variation of the beam width with the normalized channel of propagation has been observed for distinct dust densities and dust charge states. It is observed that the non‐linearity induced by the effective dielectric constant in the presence of dust grains increases the self‐filamentation of the beam, thus enhancing the effective critical power with the dust density. Some of the outcomes of our approach are in line with experimental observations. These outcomes may be useful for explaining space and laboratory plasma experiments as well as for future studies in complex plasmas.     

Modulational instability of dust acoustic waves in a dusty plasma with nonthermal electrons and ions

Effects of nonadiabaticity of variable dust charge, dust fluid temperature, trapped electrons as well as nonisothermality of ions on the amplitude modulation of dust acoustic waves in an unmagnetized dusty plasma are investigated. A modified nonlinear Schr?dinger equation (NLSE) is obtained by the standard reductive perturbation technique and is solved numerically by the split-step Fourier method. The modulational instability and the envelope solitary wave structure are found to be modified somewhat by the effects of nonthermally distributed ions and trapped electrons.