共查询到20条相似文献,搜索用时 31 毫秒
1.
The two-dimensional Vlasov equation is solved by direct integration in phase space. Two problems, namely the nonlinear evolution of the two-dimensional electrostatic two-stream instability, and the nonlinear evolution of a monochromatic wave in a two-dimensional Vlasov plasma, are studied. Comparison with previously available results is given. 相似文献
2.
Lie symmetries and conserved quantities for a two-dimensional nonlinear diffusion equation of concentration 下载免费PDF全文
The Lie symmetries and conserved quantities of a
two-dimensional nonlinear diffusion equation of concentration are
considered. Based on the invariance of the two-dimensional nonlinear
diffusion equation of concentration under the infinitesimal
transformation with respect to the generalized coordinates and time,
the determining equations of Lie symmetries are presented. The Lie
groups of transformation and infinitesimal generators of this
equation are obtained. The conserved quantities associated with the
nonlinear diffusion equation of concentration are derived by
integrating the characteristic equations. Also, the solutions of the
two-dimensional nonlinear diffusion equation of concentration can be
obtained. 相似文献
3.
4.
Instability and evolution of nonlinearly interacting water waves 总被引:1,自引:0,他引:1
We consider the modulational instability of nonlinearly interacting two-dimensional waves in deep water, which are described by a pair of two-dimensional coupled nonlinear Schr?dinger equations. We derive a nonlinear dispersion relation. The latter is numerically analyzed to obtain the regions and the associated growth rates of the modulational instability. Furthermore, we follow the long term evolution of the latter by means of computer simulations of the governing nonlinear equations and demonstrate the formation of localized coherent wave envelopes. Our results should be useful for understanding the formation and nonlinear propagation characteristics of large-amplitude freak waves in deep water. 相似文献
5.
B. Ya. Balagurov 《Journal of Experimental and Theoretical Physics》2014,118(6):971-975
The symmetry transformation proposed by A.M. Dykhne is applied to a nonlinear problem of the conductivity of two-dimensional inhomogeneous media. A number of relations are obtained between the local and effective nonlinear characteristics of the original system and its reciprocal. Reciprocity relations for even partial moments of electric field strength of arbitrary order are established for two-component two-dimensional composites. 相似文献
6.
The superintegrability of three different two-dimensional oscillators is studied: (i) a nonlinear oscillator dependent on
a parameter λ (two-dimensional version of the oscillator of Lakshmanan and Mathews), (ii) a nonlinear oscillator related to
the Riccati equation, and (iii) the standard harmonic oscillator on constant curvature spaces. They can be considered as nonlinear
deformations, or curvature-dependent versions, of the linear harmonic oscillator.
The text was submitted by the authors in English. 相似文献
7.
为了改善传统二维Arnold变换用于图像置乱加密的效果,提出了离散Arnold变换的改进方法,并将其用于图像置乱加密测试研究.该方法利用现有离散标准映射的构造思想,将传统离散二维Arnold变换表达式中第一个变换表达式所对应变换结果非线性融入第二个变换表达式,实现经典离散二维Arnold变换的非线性去拟仿射化修改,以便快速改善图像置乱加密效果.数学证明改进方法不再保持现有离散二维Arnold变换所具有的拟仿射不变性,但是改进变换仍是一种具有周期性的可逆映射,将其用于图像置乱加密时,利用其周期性或逆变换能恢复置乱前原图像.大量实验结果表明,本文所建议的改进方法是有效的,相比现有的离散Arnold变换更具有实用价值意义. 相似文献
8.
Bessel solitary wave solutions to a two-dimensional strongly nonlocal nonlinear Schrödinger equation with distributed coefficients are obtained. Bessel solitary wave solutions have unique characteristics compared with Gaussian solitary wave solutions, Laguerre-Gaussian solitary wave solutions, and Hermite-Gaussian solitary wave solutions. The generalized two-dimensional nonlocal nonlinear Schrödinger equation with distributed coefficients is investigated for the first time to our knowledge. 相似文献
9.
LIN Chang ZHANG Xiu-Lian 《理论物理通讯》2005,44(8)
The nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation is analytically investigated by using the formally variable separation approach. New analytical solutions for the governing equation of this system have been obtained for dust acoustic waves in a dust plasma for the first time. We derive exact analytical expressions for the general case of the nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation. 相似文献
10.
LIN Chang ZHANG Xiu-Lian 《理论物理通讯》2005,44(2):247-251
The nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation is analytically investigated by using the formally variable separation approach. New analytical solutions for the governing equation of this system have been obtained for dust acoustic waves in a dust plasma for the first time. We derive exact analytical expressions for the general case of the nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation. 相似文献
11.
H. C. Guo X. H. Zhang S. H. Tang Y. Q. Qin Y. Y. Zhu 《Applied physics. B, Lasers and optics》2010,98(2-3):253-259
With the nonlinear diffraction concept, we present a diffractive study of optical parametric interactions in nonlinear photonic crystals. The nonlinear diffraction concept enables the design of complicated nonlinear photonic crystal structures in an intuitive way. We show that there are two basic linear sequences, the anti-stacking and the para-stacking sequences, existing in a one-dimensional structure; and we present the realization of multiple phase-matching resonances in the combination of the two basic sequences. The parameters affecting the structure factor of a two-dimensional nonlinear photonic crystal are investigated, which indicate that not only the Ewald construction but also the relative domain size determines two-dimensional nonlinear diffractions. 相似文献
12.
RUAN Dong SUN Hong-Zhou 《理论物理通讯》2004,42(9)
In this paper nonlinear dynamical symmetries of three quantum systems are studied in detail, such as theKepler-Coulomb system and the isotropic harmonic oscillator in a two-dimensional curved space, and the generalizedpseudo-oscillators in the two-dimensional flat space. Their nonlinear spectrum generating algebras are shown to berelevant to polynomial angular momentum algebras. 相似文献
13.
An effective Hamiltonian of the two-dimensional antiferromagnetic Heisenberg model is derived by using the Holstein-Primakoff transformation. Three nonlinear coupled partial equations of motion are obtained. In the long-wavelength approximation, these equations, are reduced to the envelope function equations by the method of multiple scales. The amplitude functions satisfy the nonlinear Schrodinger equation. Introducing an inverse scatteriag transformation, the single-, two- and multi-soliton solutions in the two-dimensional antiferromagnetic Heisenberg model are investigated. 相似文献
14.
RUANDong SUNHong-Zhou 《理论物理通讯》2004,42(3):379-384
In this paper nonlinear dynamical symmetries of three quantum systems are studied in detail, such as the Kepler-Coulomb system and the isotropic harmonic oscillator in a two-dimensional curved space, and the generalized pseudo-oscillators in the two-dimensional fiat space. Their nonlinear spectrum generating algebras are shown to be relevant to polynomial angular momentum algebras. 相似文献
15.
采用变劲度系数的耦合弹簧构建一实际的两自由度弱非线性耦合系统, 用近似Lie对称性理论研究系统的一阶近似Lie对称性与近似守恒量, 得到6个一阶近似Lie对称性和一阶近似守恒量, 其中1个一阶近似守恒量实为系统的精确守恒量, 4个一阶近似守恒量为平凡的一阶近似守恒量, 只有1个一阶近似守恒量为稳定的一阶近似守恒量.
关键词:
两自由度弱非线性耦合系统
近似Lie对称性
近似守恒量 相似文献
16.
We investigate energy localization and transport in the form of discrete breathers and their movability in two-dimensional
Fermi–Pasta–Ulam(FPU) lattices. We study the dynamics of the two-dimensional Fermi–Pasta–Ulam(FPU) lattice, incorporating
the complicated effects of geometry, long-range interactions as well as nonlinear dispersion. We obtain several exact discrete
breather(DB) solutions, such as the odd-parity and even-parity DBs, compact-like DBs and moving DBs for various geometries
of the two-dimensional FPU chain. We show that DBs also exist in the same lattice in presence of next-nearest neighbour interaction.
Large-amplitude exact subsonic travelling kink-soliton solutions are obtained in such a periodic chain in presence of long-range
nonlinear dispersive interaction in the long-wavelength and weakly nonlinear limit. Such a two-dimensional FPU lattice admits
finite amplitude nonlinear sinusoidal wave (NSW) solutions with short commensurate as well as incommensurate wavelengths for
different geometries of the chain. The usefulness of these solutions for energy localization and transport in various physical
systems are discussed. 相似文献
17.
Two-dimensional discrete gap breathers in a two-dimensional discrete diatomic Klein-Gordon lattice 下载免费PDF全文
We study the existence and stability of two-dimensional discrete breathers in a two-dimensionai discrete diatomic Klein-Gordon lattice consisting of alternating light and heavy atoms, with nearest-neighbor harmonic coupling. Localized solutions to the corresponding nonlinear differential equations with frequencies inside the gap of the linear wave spectrum, i.e. two-dimensional gap breathers, are investigated numerically. The numerical results of the corresponding algebraic equations demonstrate the possibility of the existence of two-dimensional gap breathers with three types of symmetries, i.e., symmetric, twin-antisymmetric and single-antisymmetric. Their stability depends on the nonlinear on-site potential (soft or hard), the interaction potential (attractive or repulsive) and the center of the two-dimensional gap breathers (on a light or a heavy atom). 相似文献
18.
Serga AA Hillebrands B Demokritov SO Slavin AN Wierzbicki P Vasyuchka V Dzyapko O Chumak A 《Physical review letters》2005,94(16):167202
We show experimentally as well as by numerical simulation that interaction of a linear two-dimensional spin-wave packet with quasiuniform pulsed pumping leads to the formation of strongly self-focused nonlinear spin-wave bullets propagating in both forward and reversed directions. The focusing of the reversed, phase-conjugated wave bullet is stronger than that of the forward one, because not only the nonlinear four-wave self-focusing effect but also linear focusing due to two-dimensional phase conjugation contributes to the focusing of the reversed bullet. 相似文献
19.
Kannan Manikandan Murugaian Senthilvelan Roberto André Kraenkel 《The European Physical Journal B - Condensed Matter and Complex Systems》2016,89(10):218
We construct vector rogue wave solutions of the two-dimensional two coupled nonlinear Schrödinger equations with distributed coefficients, namely diffraction, nonlinearity and gain parameters through similarity transformation technique. We transform the two-dimensional two coupled variable coefficients nonlinear Schrödinger equations into Manakov equation with a constraint that connects diffraction and gain parameters with nonlinearity parameter. We investigate the characteristics of the constructed vector rogue wave solutions with four different forms of diffraction parameters. We report some interesting patterns that occur in the rogue wave structures. Further, we construct vector dark rogue wave solutions of the two-dimensional two coupled nonlinear Schrödinger equations with distributed coefficients and report some novel characteristics that we observe in the vector dark rogue wave solutions. 相似文献
20.
A. V. Golenishchev-Kutuzov V. A. Golenishchev-Kutuzov R. I. Kalimullin A. A. Potapov 《Bulletin of the Russian Academy of Sciences: Physics》2014,78(4):271-273
Specific features of the preparation and application of photonic and phononic crystals containing two-dimensional periodic domain structures are considered. Particular attention is given to the formation of two-dimensional periodic domain structures in oxide ferroelectrics using strongly focused laser beams. Specific features of the nonlinear properties of such two-dimensional structures during the propagation of optical and acoustic beams through them are described. 相似文献