Orthogonal interaction of bernstein mode with ion-acoustic wave through plasma maser effect

Interaction of Bernstein mode wave with ion-acoustic turbulence is treated as the plasma maser effect. Ion-acoustic turbulence is considered as resonant mode, propagating orthogonal to the test Bernstein mode. The external magnetic field, in the direction of ion-acoustic turbulence, is playing key role in transferring energy in upconversion process from resonant low frequency wave to the high frequency wave through modulated electric field. It is shown that the direct coupling term and the associated reverse absorbtion effect do not contribute individually to the growth or damping to the Bernstein mode. Only the polarization coupling term is found to be effective in the energy upconversion process as the external magnetic field is providing momentum in the direction of propagation of Bernstein mode. The polarization coupling term is identified to be the dominant upconversion factor in the plasma maser effect.     

Nonlinear ion-acoustic solitary waves in an electron-positron-ion plasma with relativistic positron beam

The propagation characteristics of nonlinear ion–acoustic(IA) solitary waves(SWs) are studied in thermal electron–positron–ion plasma considering the effect of relativistic positron beam. Starting from a set of fluid equations and using the reductive perturbation technique, we derive a Korteweg–de Vries(KdV) equation which governs the evolution of weakly nonlinear IA SWs in relativistic beam driven plasmas. The properties of the IA soliton are studied, and it is shown that the presence of relativistic positron beam significantly modifies the characteristics of IA solitons.     

Nonlinear interaction of a circularly polarized electromagnetic wave with a dense laser plasma

The interaction of an intense circularly polarized laser pulse with a layer of plasma of supercritical density is studied. The nonlinear skin effect for the electromagnetic field and the coefficient of collisionless absorption of the laser pulse were calculated analytically. It is shown that, in the process of interaction with the plasma, the laser pulse generates solitons propagating through the plasma layer and transferring the radiation through the opaque medium. The coefficient of transparency of the plasma layer for the soliton-like penetration of the laser radiation was calculated. The plasma parameters at which the collisionless absorption is small as compared to the transformation of the laser energy into solitons were found.     

Nonlinear propagation of ion-acoustic waves in a degenerate dense plasma

Nonlinear propagation of ion-acoustic (IA) waves in a degenerate dense plasma (with all the constituents being degenerate, for both the non-relativistic or ultrarelativistic cases) have been investigated by the reductive perturbation method. The linear dispersion relation and Korteweg–de Vries (KdV) equation have been derived, and the numerical solutions of KdV equation have been analysed to identify the basic features of electrostatic solitary structures that may form in such a degenerate dense plasma. The implications of our results in compact astrophysical objects, particularly, in white dwarfs and neutron stars, have been briefly discussed.     

Electron kinetic effects in the nonlinear evolution of a driven ion-acoustic wave

The electron kinetic effects are shown to play an important role in the nonlinear evolution of a driven ion-acoustic wave. The numerical simulation results obtained (i) with a hybrid code, in which the electrons behave as a fluid and the ions are described along the particle-in-cell (PIC) method, are compared with those obtained (ii) with a full-PIC code, in which the kinetic effects on both species are retained. The electron kinetic effects interplay with the usual fluid-type nonlinearity to give rise to a broadband spectrum of ion-acoustic waves saturated at a low level, even in the case of a strong excitation. This low asymptotic level might solve the long-standing problem of the small stimulated Brillouin scattering reflectivity observed in laser-plasma interaction experiments.     

On the mass of a wave packet in plasma

The relativistic mass density which is transported by a quasi-monochromatic transverse wave packet is derived. The wave packet is assumed to propagate in isotropic cold collisionless plasma. The co-ordinate frame moving with the group velocity appears as the rest frame for both the mass density and the total mass of the wave packet. The equivalence of the energy-mass relation and the dispersion equation is demonstrated.     

Long-range perturbations produced by a localized packet of ion-acoustic waves in a collisionless plasma

We demonstrate the in situ detection of cold ⁸⁷Rb atoms near a dielectric surface using the absorption of a weak, resonant evanescent wave. We have used this technique in time of flight experiments determining the density of atoms falling on the surface. A quantitative understanding of the measured curve was obtained using a detailed calculation of the evanescent intensity distribution. We have also used it to detect atoms trapped near the surface in a standing-wave optical dipole potential. This trap was loaded by inelastic bouncing on a strong, repulsive evanescent potential. We estimate that we trap 1.5×10⁴ atoms at a density 100 times higher than the falling atoms. Received 14 May 2002 Published online 8 October 2002 RID="a" ID="a"e-mail: spreeuw@science.uva.nl     

Dust ion-acoustic solitary waves in a hot adiabatic magnetized dusty plasma

The basic features of obliquely propagating dust ion-acoustic (DIA) solitary waves in a hot adiabatic magnetized dusty plasma (containing adiabatic inertia-less electrons, adiabatic inertial ions, and negatively charged static dust) have been investigated. The reductive perturbation method has been employed to derive the Korteweg-de Vries (KdV) equation which admits a small amplitude solitary wave solution. The combined effects of plasma particle (electron and ion) adiabaticity, ion-dust collision, and external magnetic field (obliqueness), which are found to significantly modify the basic features of the small but finite-amplitude DIA solitary waves are explicitly examined. The implications of our results in space and laboratory dusty plasmas are briefly discussed.     

Dynamically stable electron bunches in beam interaction with an electromagnetic wave packet

Nonlinear interaction of electron beam with a whistler wave packet that effectively dissipates through collisions or wave leakage is studied. Independently of the dissipation type and nature of waves, self-organization of the beam structure leads to the formation of bunches continuously decelerated by waves. Strong dissipation prevents phase mixing required for the quasilinear theory and keeps wave phases in the packet correlated. Thus, dynamically stable bunches are present together with a plateau in the velocity distribution; asymptotically, wave emission by bunches is the main process.     

Nonlinear evolution of a relativistically strong electromagnetic wave in self-created electron-positron plasma

The nonlinear interaction between the electron-positron pairs produced by an electromagnetic wave in plasma and the wave leads to damping of the wave, frequency upshift, change of polarization, and particle acceleration. The case of a circularly polarized wave is investigated in the framework of the relativistic Vlasov equation with a source term based on the Schwinger formula for the pair creation rate.     

Nonlinear adiabatic models of ion-acoustic waves in dust plasma

Nonlinear adiabatic models of ion-acoustic waves in a dust plasma are developed. The problem of the structure of subsonic periodic and supersonic solitary ion-acoustic waves is exactly solved analytically under the assumption of a constant charge of dust particles; the critical Mach numbers for the solitary wave are determined. The problem of the wave structure is solved numerically for the case when the charge of dust particles was assumed to be variable.     

Effect of electron-ion collision on the ion-acoustic solitary wave in a relativistic plasma

Summary We have considered the effect of electron-ion collision on the structure of the solitary wave in a relativistic unmagnetized plasma. In the present analysis we have considered ions to be cold, the electrons hot. The equation obtained for ion velocity is not the usual KdV type but a perturbed version of it, where the perturbing term is proportional to the electron-ion collision frequency. Lastly we have used the method of Bogoliubov-Mitropolsky to study the change in the solitary-wave profile due to this perturbation.     

Ultrashort videopulses of a transverse wave field in a spin system with an anisotropic spin-spin interaction

The propagation is analyzed of a circularly polarized ultrashort videopulse of a transverse wave field in a spin system with an anisotropic spin-spin interaction. Several physical realizations of the given model are proposed. Soliton-like solutions are obtained without approximating the rotating wave and slowly varying envelopes. It is shown that the formation of a connected state of a two-component videopulse is possible for propagation velocities falling in a specific interval of values.Pacific Ocean Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 114–119, July, 1993.     

Nonlinear propagation of ion plasma waves in dust-ion plasma including quantum-relativistic effect

In this paper we have theoretically investigated the quantum and relativistic effects on ion plasma wave in an unmagnetised dust-ion plasma. By using the method of normal mode analysis, we have obtained a linear dispersion relation. It has been analysed numerically for quantum and relativistic effects on the propagation of ion plasma wave. By using the standard reductive perturbation technique, we have derived a Korteweg–de Vries (KdV) equation which describes the nonlinear propagation of the wave. Numerically, it is shown that only compressive type of soliton can exist in the plasma under consideration. It is found that the solitary wave profile depends significantly on the quantum and relativistic parameters. The dust size, dust charge and the dust number density are also shown to have significant influences on these solitary waves. The results of this present investigation have some relevance to the nonlinear propagation of ion plasma wave in some astrophysical, space and laboratory plasma environments.     

Mode transitions on the surface dust ion-acoustic wave in a semibounded dusty plasma

The effects of elongated rotating dust grains on the mode transitions of the dispersion relation of the surface dust ion-acoustic waves are investigated in a semi-bounded dusty plasma. The dispersion relation of the surface dust ion-acoustic wave is obtained by the plasma dielectric function with the specular reflection boundary condition. The result shows the existence of the dust ion-acoustic resonance modes in small and large wave number regions. It is also shown that the surface wave would be propagated in intermediate wave number domains. It is interesting to note that the wave propagation domain has been diminished with an increase of the rotation frequency.     

Nonlinear stationary solutions for coupled electron-plasma and ion-acoustic waves in a plasma

A broad range of nonlinear stationary solutions are obtained for the propagation of coupled electron-plasma and ion-acoustic waves in the plasma. They consist of periodic, quasi-periodic, soliton type, highly irregular (stochastic) and ion-sheath solutions.     

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由色散方程和流体方程推导得到了横等离激元和对等离子体相互作用的非线性控制方程,利用场论的方法构建非线性控制方程的拉格朗日密度函数并求得相互作用过程中守恒的等离激元数和总能量。通过标度变换发现横等离激元由于调制不稳定性将坍塌形成小尺度的局域结构。在坍塌过程中横等离激元产生的有质动力随场强的增强而增强。由于有质动力对粒子的排斥,对等离子体中将产生小尺度的密度空穴。