非均匀量子等离子体中的非线性波

本文探讨具有温度和密度梯度的非均匀量子等离子体系统, 获得了该系统在离子与中子碰撞频率较低情况下的二维非线性流体动力学方程． 求得了非均匀量子等离子体中的电势的冲击、爆炸和旋涡解．分析讨论了在致密天体物理环境中静电势的变化, 结果表明电势的冲击波的幅度和爆炸波的宽度,都随密度的增大(即随无维量子参量的减小)而增大, 但随漂移速度的增大(即随密度和温度梯度的增大)而减小; 静电势随时空相位的增大而趋向于稳定值, 系统最后达到稳定的状态． 旋涡解表明,旋涡静电势的时空分布呈现稳定的周期性的旋涡流．     

噪声在外加周期信号控制强湍中的作用研究

研究了噪声在控制中的作用.研究发现,较小强度的偏噪声信号能够使系统失去层流态,重新进入无序态,此时模式之间的广义相同步也失去了;而噪声强度较大时,系统则能够维持准周期的层流态,模式相位之间依然能够达到广义相同步. 关键词： 相同步 时空混沌 湍流 非线性漂移波     

Nonlinear waves in a plasma cylinder

Nonlinear electron plasma waves in a cold plasma bounded by a cylindrical dielectric are investigated using the exact electron fluid equations. After the spatial wave structure is determined, a set of nonlinear equations governing the temporal behavior of the field quantities is solved. It is shown that finite amplitude waves and explosively unstable behavior can occur     

Experimental observation of strong coupling effects on the dispersion of dust acoustic waves in a plasma

The dispersion properties of low frequency dust acoustic waves in the strong coupling regime are investigated experimentally in an argon plasma embedded with a mixture of kaolin and MnO₂ dust particles. The neutral pressure is varied over a wide range to change the collisional properties of the dusty plasma. In the low collisional regime the turnover of the dispersion curve at higher wave numbers and the resultant region of ∂ω/∂k<0$\partial \omega /\partial k<0$ are identified as signatures of dust–dust correlations. In the high collisional regime dust neutral collisions produce a similar effect and prevent an unambiguous identification of strong coupling effects.     

Thermal hopping of single charges in the strong dissipation limit

Macroscopic charge quantization is analyzed in the case in which thermal activation across trapping barriers dominates over tunneling and the barrier heights are comparable to the charging and thermal energies. Barrier suppression, the image force due to the finite electron charge, and the contribution of unstable charge states are considered. The effects considered may partly account for recent experimental data on high-temperature single-electronics in semiconductor and granulated systems. Pis’ma Zh. éksp. Teor. Fiz. 64, No. 8, 543–548 (25 October 1996) Published in English in the original Russian journal. Edited by Steve Torstveit.     

Nonlinear Langmuir waves in a relativisitc plasma

Langmuir waves in a relativistic plasma are considered using kinetic equations without consideration of captured particles. The frequency shift found for such waves contains contributions from four-wave interaction, and a contribution produced by the relativistic dependence of electron momentum on velocity.     

Nonlinear electrostatic waves in a magnetized plasma

The modulational interaction of finite-amplitude high-frequency electrostatic waves propagating at an arbitrary angle to an external magnetic field with slow plasma motion is considered. A set of nonlinear evolution equations describing the interaction is obtained. New types of solitary waves propagating at near sonic speeds are found.     

Nonlinear waves in a rotating plasma cylinder

Previous work on exact cylindrical surface waves in a nonneutral cold-electron plasma bounded by a dielectric is extended to include plasma rotation. A set of nonlinear rate equations describing the temporal behavior of the system is derived by first determining an appropriate spatial wave structure. Physically relevant periodic solutions are obtained     

Nonlinear absorption of cyclotron waves in a plasma

Institute of Earth Physics, Academy of Sciences of the USSR. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 31, No. 3, pp. 274–278, March, 1988.     

Shilnikov sense chaos in a simple three-dimensional system

The Shilnikov sense Smale horseshoe chaos in a simple 3D nonlinear system is studied. The proportional integral derivative (PID) controller is improved by introducing the quadratic and cubic nonlinearities into the governing equations. For the discussion of chaos, the bifurcate parameter value is selected in a reasonable regime at the requirement of the Shilnikov theorem. The analytic expression of the Shilnikov type homoclinic orbit is accomplished. It depends on the series form of the manifolds surrounding the saddle-focus equilibrium. Then the methodology is extended to research the dynamical behaviours of the simplified solar-wind-driven-magnetosphere-ionosphere system. As is illustrated, the Lyapunov characteristic exponent spectra of the two systems indicate the existence of chaotic attractor under some specific parameter conditions.     

Nonlinear electrostatic surface waves in a semi-infinite plasma

The nonlinear equations which govern the filamentation of a large-amplitude high-frequency electrostatic surface wave are studied considering solutions in the form of stationary traveling waves. It is shown that solitary surface waves exist at certain amplitude and phase conditions.     

A nonlinear wave coupling algorithm and its programing and application in plasma turbulences

The fully developed turbulence can be regarded as a nonlinear system, with wave coupling inside, which causes the nonlinear energy to transfer, and drives the turbulence to develop further or be suppressed. Spectral analysis is one of the most effective methods to study turbulence system. In order to apply it to the study of the nonlinear wave coupling process of edge plasma turbulence, an efficient algorithm based on spectral analysis technology is proposed to solve the nonlinear wave coupling equation. The algorithm is based on a mandatory temporal static condition with the nonideal spectra separated from the ideal spectra. The realization idea and programing flow are given. According to the characteristics of plasma turbulence, the simulation data are constructed and used to verify the algorithm and its implementation program. The simulation results and experimental results show the accuracy of the algorithm and the corresponding program, which can play a great role in the studying the energy transfer in edge plasma turbulences. As an application, the energy cascade analysis of typical edge plasma turbulence is carried out by using the results of a case calculation. Consequently, a physical picture of the energy transfer in a kind of fully developed turbulence is constructed, which confirms that the energy transfer in this turbulent system develops from lower-frequency region to higher-frequency region and from linear growing wave to damping wave.     

Nonlinear waves in a fluid-filled thin viscoelastic tube

In the present paper the propagation property of nonlinear waves in a thin viscoelastic tube filled with incom-pressible inviscid fluid is studied.The tube is considered to be made of an incompressible isotropic viscoelastic material described by Kelvin-Voigt model.Using the mass conservation and the momentum theorem of the fluid and radial dynamic equilibrium of an element of the tube wall,a set of nonlinear partial differential equations governing the prop-agation of nonlinear pressure wave in the solid-liquid coupled system is obtained.In the long-wave approximation the nonlinear far-field equations can be derived employing the reductive perturbation technique (RPT).Selecting the expo-nent α of the perturbation parameter in Gardner-Morikawa transformation according to the order of viscous coefficient η,three kinds of evolution equations with soliton solution,i.e.Korteweg-de Vries (KdV)-Burgers,KdV and Burgers equations are deduced.By means of the method of traveling-wave solution and numerical calculation,the propagation properties of solitary waves corresponding with these evolution equations are analysed in detail.Finally,as a example of practical application,the propagation of pressure pulses in large blood vessels is discussed.     

Nonlinear acoustic waves in a collisional self-gravitating dusty plasma

Using the reductive perturbation method,we investigate the small amplitude nonlinear acoustic wave in a collisional self-gravitating dusty plasma.The result shows that the small amplitude dust acoustic wave can be expressed by a modified Korteweg-de Vries equation,and the nonlinear wave is instable because of the collisions between the neutral gas molecules and the charged particles.     

Nonlinear waves in a waveguide partially filled with a plasma

Nonlinear waves have been studied in a circular waveguide partially filled with a cold magnetized collisionless plasma. The solution obtained is periodical with the frequency increasing as a square root of the amplitude of the solution in the first approximation.The author is indebted to K.Jungwirth, R.Klíma and J.Preinhaelter for valuable discussions.