共查询到20条相似文献,搜索用时 187 毫秒
1.
S. O. Shiryaeva 《Technical Physics》2011,56(3):335-344
A dispersion relation is derived for capillary waves with an arbitrary symmetry on the surface of a charged jet of a finite-conductivity
viscous liquid placed in an electric field collinear with the axis of the jet. Analytical calculations are carried out in
an approximation that is linear in dimensionless wave amplitude. In the case of axisymmetric waves, the instability of which
causes disintegration of the jet into drops, the finiteness of the potential equalization rate has a noticeable effect only
for jets of poorly conducting liquids. The charge relaxation shows up in that “purely relaxation” periodic and aperiodic liquid
flows arise. When the conductivity of the liquid declines, the instability growth rates for unstable waves increase and their
spectrum extends toward short waves. A charge present on the surface of the jet enhances its instability. An increase in the
charge surface diffusion coefficient variously influences the capillary and relaxation branches of the solution: the damping
ratio increases in the former case and decreases in the latter. As the diffusion coefficient rises, relaxation flows may become
unstable. 相似文献
2.
It is shown that electrohydrodynamic waves similar to gravity waves at the interface of two liquids can propagate in a semiconductor
structure composed of two semiconductor layers with different charge carrier densities and placed in a transverse electric
field. The conditions for existence of such waves are specified. The linear and nonlinear modes of wave propagation are studied.
State Technical University, Ulianovsk, Russia, Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40,
No. 9, pp. 1164–11171, September, 1997. 相似文献
3.
V. P. Ruban 《JETP Letters》2011,94(3):177-181
Numerical simulations of fully nonlinear equations of motion for long-crested waves at deep water demonstrate that in elongate
wave groups the formation of extreme waves occurs most intensively if in an initial state the wave fronts are oriented obliquely
to the direction of the group. An “optimal” angle, resulting in the highest rogue waves, depends on initial wave amplitude
and group width, and it is about 18–28 degrees in a practically important range of parameters. 相似文献
4.
The boundary problem of nonlinear optics was investigated for a trial wave reflected (refracted) by an excited region of a
nonlinear medium considered as a system of multilevel atoms in the spectrum of which there are two closely-spaced energy levels
excited by a powerful quasi-resonant radiation. It is shown that under interference conditions of the atomic states in the
field of the trial and resonance waves there exist three types of waves: an inverse wave and two polarization waves. By way
of extension of the Ewald-Oseen procedure to this case a formula for the complex refractive index of a nonlinear medium for
the three types of waves as well as a generalized extinction theorem have been obtained. It is shown that the trial wave can
be amplified without inversion of the interfering atomic states and that the refractive index can be markedly changed at certain
concentrations of atoms in the medium. General formulas for the amplitudes of the reflected and refracted waves have been
obtained.
Ul’yanovsk State University, 42, Tolstoi Str., Ul’yanovsk, 432700, Russia. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 65, No. 4, pp. 568–575, July–August, 1998. 相似文献
5.
Two opposite gravity-capillary waves of equal frequency give rise to the formation of a standing wave on the ocean surface and, thus, in the nonlinear approximation, generate a sound wave of twofold frequency with an amplitude proportional to the squared height of the surface wave [1]. This effect, being caused by the nonlinear interaction of opposite surface waves, can give rise to the radiation of sound waves in both ocean and atmosphere [2]. Opposite waves can appear in the ocean as a result of different ocean-atmosphere interactions and, in particular, as a result of the blocking of capillary waves on the slope of a gravity wave. 相似文献
6.
《Physics letters. A》2003,280(2-3):226-233
The modulational instability of dust acoustic waves in a dusty plasma with non-adiabatic dust charge fluctuation is studied. Using the perturbation method, a modified nonlinear Schrödinger equation containing a damping term that comes from the effect of dust charge variation is derived. It is found that the modulational instability of the wave packet and the propagation characters of the envelope solitary waves are modified significantly by the non-adiabatic dust charge fluctuation. 相似文献
7.
S. O. Shiryaeva 《Technical Physics》2011,56(6):782-787
The influence of the finiteness of the charge transfer rate on the electrostatic instability of the lateral surface of a viscous
liquid jet is studied. The study is based on the analysis of a dispersion relation for flexural-deformation capillary waves
on the surface of the jet with allowance for charge relaxation. The jet is subjected to a superposition of two electrostatic
fields one of which is collinear with the jet’s axis and the other is directed radially to the former. It is found that the
finiteness of the potential equalization rate influences jets of a poorly conducting liquid most strongly. The charge relaxation
shows up in the appearance of both periodic and aperiodic “purely relaxation” flows. Relaxation flows give rise to electrostatic
instability in low-permittivity liquids. When the conductivity of the liquid drops, the instability growth rate of relaxation
waves grows and their spectrum expands toward shorter waves. An increase in the charge surface diffusion coefficient introduces
destabilization into the relaxation flows of the liquid, which may eventually become unstable. 相似文献
8.
9.
We present a complete theoretical analysis of the periodic and non-periodic travelling waves in a diatomic chain model, in
the continuum limit by incorporating nonlinear sixth order polarization potential (φ6) at the anion site. We have formulated a nonlinear lattice dynamical theory in which various energy curves are obtained for
different types and magnitudes of the core-shell force constants. For periodic solutions, we have obtained two types of commensurate
wave amplitudes which propagate in the opposite direction with respect to each other. For nonperiodic solutions, we have obtained
various travelling excitations such as kink, antikink, excitons etc. for different values of the mass ratio and velocity parameter.
The dipole moment per unit charge for SrTiO3 has been calculated and it is found that the nonlinear excitations in this model carry large amount of energy as compared
to those obtained from harmonic and anharmonic optical phonons in the φ4-polarizable model. 相似文献
10.
A. I. Grigor’ev S. O. Shiryaeva V. A. Koromyslov D. F. Belonozhko 《Technical Physics》1997,42(8):877-883
A dispersion relation is derived and analyzed for the spectrum of capillary motion at a charged flat surface of viscous liquid
covering a solid substrate with a layer of finite thickness. It is shown that for waves whose wavelengths are comparable with
the layer thickness, viscous damping at the solid bottom begins to play an important role. The spectrum of capillary liquid
motion established in this system has high and low wave number limits. The damping rates of the capillary liquid motion with
wave lengths comparable with the layer thickness are increased considerably and the Tonks-Frenkel instability growth rates
are reduced compared with those for a liquid of infinite depth.
Zh. Tekh. Fiz. 67, 27–33 (August 1997) 相似文献
11.
S. N. Artemenko 《Journal of Experimental and Theoretical Physics》1997,84(4):823-832
The reported study of charge density waves at low temperatures is based on a microscopic theory. One feature of a charge density
wave at low temperatures is a large shift in the chemical potential near its defects, such as solitons, dislocations, and
pinning centers, which leads to a higher conductivity of material along chains when the charge density wave is immobile, and
the wave dynamics is controlled by this shift. Equations describing the dynamics of a charge density wave have been derived
and used to estimate the velocity of 2π-solitons along conducting chains. The resulting soliton mobility has proved to be low and makes a small contribution to the
conductivity. The large shift in the chemical potential near strong pinning centers can lead to a considerable increase in
linear conductivity along conducting chains.
Zh. éksp. Teor. Fiz. 111, 1494–1512 (April 1997) 相似文献
12.
Yu. Ya. Trifonov 《Journal of Engineering Thermophysics》2008,17(1):30-52
This paper is devoted to a theoretical analysis of nonlinear two-dimensional waves using the Navier-Stokes equations in their
full statement. Steady-state travelling wave regimes have been found and an analysis of their linear stability has been carried
out. It is shown that the flow regimes obtained using the Navier-Stokes equations are qualitatively different from the solutions
of Shkadov’s integral approach starting from some values of the Kapitza number. It is also found that the wave regimes of
the Navier-Stokes equations have an internal vortex at moderate Reynolds numbers. The results obtained using “the regularized
integral model” are in excellent agreement with the Navier-Stokes calculations for Re/Ka ≤2. Unlike the solutions found using an integral approach, it is shown that only a few types of nonlinear waves exist when
the full Navier-Stokes equations are considered.
The text was submitted by the author in English. 相似文献
13.
A dispersion relation is proposed and analyzed for the spectrum of capillary motion at a charged flat liquid surface with
allowance made for the finite rate of charge redistribution accompanying equalization of the potential as a result of the
wave deformation of the free surface. It is shown that when the conductivity of the liquid is low, a highly charged surface
becomes unstable as a result of an increase in the amplitude of the aperiodic chargerelaxation motion of the liquid and not
of the wave motion, as is observed for highly conducting media. The finite rate of charge redistribution strongly influences
the structure of the capillary motion spectrum of the liquid and the conditions for the establishment of instability of its
charged surface when the characteristic charge relaxation time is comparable with the characteristic time for equalization
of the wave deformations of the free surface of the liquid.
Zh. Tekh. Fiz. 67, 34–41 (August 1997) 相似文献
14.
E. Tobisch 《Journal of Experimental and Theoretical Physics》2014,119(2):359-365
We consider nonlinear gravity-capillary waves with the nonlinearity parameter ? ~ 0.1–0.25. For this nonlinearity, time scale separation does not occur and the kinetic wave equation does not hold. An energy cascade in this case is built at the dynamic time scale (D-cascade) and is computed by the increment chain equation method first introduced in [15]. We for the first time compute an analytic expression for the energy spectrum of nonlinear gravity-capillary waves as an explicit function of the ratio of surface tension to the gravity acceleration. We show that its two limits—pure capillary and pure gravity waves on a fluid surface—coincide with the previously obtained results. We also discuss relations of the D-cascade model with a few known models used in the theory of nonlinear waves such as Zakharov’s equation, resonance of modes with nonlinear Stokes-corrected frequencies, and the Benjamin-Feir index. These connections are crucial in understanding and forecasting specifics of the energy transport in a variety of multicomponent wave dynamics, from oceanography to optics, from plasma physics to acoustics. 相似文献
15.
Using the Calogero model as an example, we show that the transport in interacting nondissipative electronic systems is essentially nonlinear and unstable. Nonlinear effects are due to the curvature of the electronic spectrum near the Fermi energy. As is typical for nonlinear systems, a propagating semiclassical wave packet develops a shock wave at a finite time. A wave packet collapses into oscillatory features which further evolve into regularly structured localized pulses carrying a fractionally quantized charge. The Calogero model can be used to describe fractional quantum Hall edge states. We discuss perspectives of observation of quantum shock waves and a direct measurement of the fractional charge in fractional quantum Hall edge states. 相似文献
16.
We study the effect of striction plasma density disturbances on the generation intensity of longitudional cold and plasma
oscillations due to polarization of the magnetic field-aligned ionospheric plasma irregularities with δNo<0 by a powerful radio wave. It is assumed that the plasma density level inside the irregularity intersects the upper-hybrid
resonance level, in the vicinity of which the cold oscillations excited directly by a powerful radio wave are transformed
to shorter-wave plasma oscillations. We consider the short plasma wave limit to reduce the problem to a system of two coupled
equations for the cold wave induction and plasma wave electric field. The first equation is supplemented by a local source
equal to the integral of the plasma wave electric field in the resonance region. The second equation involves the cold wave
induction at the resonance point and describes the electric field of interacting waves in the resonance vicinity. We use simplifications
connected with the small absorption of plasma waves propagating inside the irregularity and weak radiation of these waves
outside the irregularity. These conditions correspond to the generation of eigenmodes of plasma oscillations trapped in the
irregularity. We have obtained a resonance-type nonlinear equation for the electric field intensity (or energy flux) of eigenmode
plasma waves with allowance for striction disturbances of the plasma density profile in the resonance region. It is shown
that the striction expulsion of plasma is responsible for the occurrence of coefficients describing the change in the intensity
of excitation and radiation of plasma waves at the irregularity boundary. Such an expulsion leads to variations of the efficient
generation band of plasma eigenmodes with the total phase increment of the wave in the irregularity. It also leads to a change
in the phase shift of the plasma wave reflected from the resonance. These coefficients and the nonlinear phase shift are expressed
in terms of real wave functions of the nonlinear Airy equation which describes the electric field of the excited waves in
the resonance vicinity when the dissipation is absent.
Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences, Troitsk, Moscow region,
Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 3, pp. 270–297, March, 1998. 相似文献
17.
A. P. Bogatov 《Journal of Russian Laser Research》1994,15(5):417-453
The electromagnetic field inside a nonlinear active medium of a laser is considered as a system of counterpropagating waves.
Such an approach changes radically an earlier studied behavior of the lateral field instability due to self-deformaion (or
self-focusing). In our calculations we used an expression for a laser field in the form of two “strong” counterpropagating
waves whose complex amplitudes have weak perturbations. Amplitude perturbations of each of the “strong” waves can be presented
by two spatial harmonics corresponding to two weak perturbation waves with wave vectors making some tilted angle ±φ with the
cavity axis. Thus six waves would participate in the interaction: two counterpropagating strong waves and two pairs of weak
waves. Using this approach, we have developed a theory for the propagation of four “weak” perturbation waves in a nonlinear
amplifying medium in the presence of two counterpropagating “strong” waves. It is shown that perturbation waves with tilted
angle φ⋍0.5–1.2° inside the active region, and respecively, with the side lobes of the far-field pattern at ∼1.7–4°, have
the greatest growth increment. These perturbation waves produce lateral intensity modulation with period 10–30 μm for the
0.85 μm lasing wavelength. The appearance of such waves corresponds to the instability threshold of a homogeneous lateral
distribution of optical power in a diode laser.
The present theory makes it possible to investigate the stability of the homogeneous lateral optical intensity distribution
in a diode laser of any design. This allows one to choose a suitable design of a laser with a homogeneous lateral distribution
at high radiation power.
Translated from Preprint No. 43 (1992) of the Lebedev Physics Institute, Russian Academy of Sciences. 相似文献
18.
Quantum mechanics equations for a system of the Bose particles are represented in the form of material field equations. A
nonlinear equation for the macroscopic one-particle wave function is derived. Using the Krylov–Bogolyubov–Mitropol’skii method
for equations in partial derivatives, nonlinear waves in the Bose–Einstein condensate are investigated. In the cubic approximation,
dispersion relations for waves are derived and nonlinear frequency shift is calculated in the first- and third-order approximations
for the interaction radius. 相似文献
19.
An analytical study on nonlinear evolution of Langmuir waves in warm electron-positron-dusty plasmas is presented. The massive dust grains of either positively or negatively charged are assumed to form a fixed charge neutralizing background. A perturbative analysis of the fluid-Maxwell's equations confirms that the excited Langmuir waves phase-mix and eventually break, even at arbitrarily low amplitudes. It is shown that the nature of the dust-charge as well as the amount of dust grains can significantly influence the Langmuir wave phase-mixing process. The phase-mixing time is also found to increase with the temperature. 相似文献
20.
The structure of the capillary-relaxation motion spectrum in a liquid with a charged free surface has been investigated taking into account the viscosity relaxation effect. On the basis of numerical analysis of the dispersion equation for the wave motion in a viscoelastic incompressible liquid, it is shown that for a given wave number the range of characteristic relaxation times in which relaxation-type wave motion exists is limited and expands with increasing wave number. The growth rate of instability of the charged liquid surface markedly depends on the characteristic relaxation time and increases with its growth; in liquids with elastic properties, the energy dissipation rate of capillary motion is enhanced. At a surface charge density that is supercritical for the onset of Tonks-Frenkel instability, both purely gravitational waves and waves of a relaxational nature exist. 相似文献