共查询到20条相似文献,搜索用时 15 毫秒
1.
The problem of surface sound propagation in the presence of external high frequency dipole electric field is investigated
using Vlasov-Poisson equations. The structure of the electric field of these surface waves is also determined. It has been
found that the ion sound waves that exist in the presence of external high frequency waves are true surface waves while those
without the external field are quasi-surface waves as the former waves decay within one wavelength away from the surface. 相似文献
2.
Due to the presence of a relatively cold electron component in a plasma, the ion acoustic solitary wave of a given width has a larger amplitude. When the temperature difference between the two electron components is sufficiently large, the strength of dispersion is reduced to an extent that a solitary solution is no longer possible. 相似文献
3.
Long-wavelength ion acoustic waves in the presence of propagating short-wavelength electron plasma waves are examined. The influence of the high frequency oscillations is to decrease the phase velocity and the damping distance of the ion wave. 相似文献
4.
5.
H.L. Pécseli 《Physics letters. A》1976,58(4):216-218
The dielectric function for long-wavelength, low-frequency ion acoustic waves in the presence of short-wavelength, high-frequency electron oscillations is presented, where the ions are described by the collision-free Vlasov equation. The effect of the electron oscillations can be appropriately described by the introduction of an effective electron temperature. 相似文献
6.
The propagation of ion-acoustic K-dV solitary waves in weakly inhomogeneous, collisionless plasmas with gradients both in
the density and the temperature of the ions has been considered. The electrons are assumed to be hot and isothermal, and the
ions to be warm and adiabatic. The reductive perturbation analysis of the fluid equations is then carried out. The zero order
quantities existing in the system due to the presence of the inhomogeneities are taken into account consistently and a set
of ‘stretched coordinates’ appropriate for the inhomogeneous system is employed. A more general modified K-dV equation has
been derived and its soliton solution is obtained explicitly. It is shown that as the soliton propagates along the temperature
gradient, its amplitude and the velocity decrease, and the width increases. Further, it is found that when the two gradients
are in opposite directions, the amplitude of the soliton remains constant. 相似文献
7.
8.
S. Mahmood N. Akhtar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(2):217-222
Linear and nonlinear ion acoustic waves in the presence of adiabatically heated ions in magnetized electron-positron-ion plasmas
are studied. The Sagdeev potential approach is employed to obtain the energy integral equation in such a mulitcomponent plasma
using fluid theory. It is found that electron density humps are formed in the subsonic region in magnetized electron-positron-ion
plasmas. The amplitude of electron density hump is decreased with the increase of hot ion temperature in electron-positron-ion
plasmas. However, the increase in positron concentration and obliqueness of the wave increases the amplitude of nonlinear
structure. The increase in positron concentration also reduces the width of the nonlinear structure in a magnetized multicomponent
plasma. The numerical solutions in the form of solitary pulses are also presented for different plasma cases. The results
may be applicable to astrophysical plasma situations, where magnetized electron-positron-ion plasma with hot ions can exist. 相似文献
9.
L. Aubrecht 《Czechoslovak Journal of Physics》1968,18(12):1602-1609
The propagation of longitudinal acoustic waves in the ion gas in an external electric field is studied theoretically. The results are compared with properties of waves in space without the external field. The phase velocities, damping factors and the influence of parameters of the gas on the properties of ion waves is discussed.In conclusion, the author would like to express his thanks to Prof. J. Kracík DrSc., for valuable advice and suggestions. 相似文献
10.
Gerald F. Thomas 《Optics Communications》1983,47(3):196-198
For a two-level system the net probability for stimulated one-photon emission in the presence of a static electric field is calculated within the rotating-wave approximation and under the assumption that the static field strength (ES) is considerably less than the oscillating field strength (EO). Besides contributing to the power broadening of the emission signal and the Rabi flopping frequency, the static field shifts the resonance towards the blue in the amount 2ES/EO. 相似文献
11.
The periodic space charge layers formed in semiconducting superlattice structures can be used for direct electromagnetic generation of high frequency acoustic waves. The mechanism for and resonant nature of the acoustic generation are discussed. 相似文献
12.
Asif Shah 《Physics letters. A》2009,373(45):4164-4168
The Korteweg-de Vries-Burger (KdVB) equation is derived for ion acoustic shock waves in a weakly relativistic electron-positron-ion plasma. Electrons, positrons are considered isothermal and ions are relativistic. The travelling wave solution has been acquired by employing the tangent hyperbolic method. The vivid display of the graphical results is presented and analyzed. It is observed that amplitude and steepness of the shock wave decrease with increase of the relativistic streaming factor, the positron concentration and they increase with the increase of the coefficient of kinematic viscosity and vice versa. It is determined that at low temperature the shock wave propagates, whereas at very high temperature the solitary wave propagates in the system. The results may have relevance in astrophysical plasmas as well as in inertial confinement fusion plasmas. 相似文献
13.
The temporal characteristics of the X-ray emission from a laser irradiated Ai target in a 20 kV/cm electric field are measured with electronic detectors. Spatial and spectral distributions of the X-ray radiation are evaluated using a pinhole camera and filter technique. 相似文献
14.
Electron acoustic(EA) solitary waves(SWs) are studied in an unmagnetized plasma consisting of hot electrons(following Cairns-Tsalli distribution), inertial cold electrons, and stationary ions.By employing a reductive perturbation technique(RPT), the nonlinear Korteweg–de Vries(KdV) equation is derived and its SW solution is analyzed. Here, the effects of plasma parameters such as the nonextensivity parameter(q), the nonthermality of electrons(α), and the cold-to-hot electron density ratio(β) are investigated. 相似文献
15.
Hamid Reza Pakzad 《Indian Journal of Physics》2009,83(11):1605-1613
The Korteweg-de Vries equation for a weakly relativistic ion acoustic wave propagating in oollisionless plasma containing
nonthermal electron, positron and warm ion is derived. The effects of the ion temperature, nonthermal parameter and relativistic
effect on the amplitude, width and energy of soliton are studied. 相似文献
16.
A WKB solution for the propagation of a solitary ion acoustic wave in a plasma with a density gradient is obtained. 相似文献
17.
18.
The excitation and propagation of finite-amplitude low-frequency solitary waves are investigated in an argon plasma impregnated with kaolin dust particles. A nonlinear longitudinal dust acoustic solitary wave is excited by pulse modulating the discharge voltage with a negative potential. It is found that the velocity of the solitary wave increases and the width decreases with the increase of the modulating voltage, but the product of the solitary wave amplitude and the square of the width remains nearly constant. The experimental findings are compared with analytic soliton solutions of a model Korteveg-de Vries equation. 相似文献
19.
The modulational instability of ion acoustic waves is studied in the presence of a dc magnetic field, taking the ion temperature into account. It is well known that the instability sets in for wave numbers exceeding 1.47 kD when there is no magnetic field and the ion temperature is negligible. The instability behaviour, however, changes drastically when either the magnetic field is switched on or the ion temperature becomes important or both. In general three different regions emerge wherein the waves becomes modulationally unstable. The relative sizes of these regions change as the magnetic field, the angle of propagation and the ion temperature are varied. 相似文献
20.
Kalyan Sinha 《Letters in Mathematical Physics》1976,1(3):251-257
The decay-rate of an eigenstate into the continuum is calculated in a simple 1-dimensional model, when a small uniform electric field is switched on. It is shown that this rate is very sensitive to changes in the field strength, in conformity with experimental observations.Supported by the Fonds National Suisse. 相似文献