Reflection Of Plasma Waves Research Articles

Plasma Wave Reflection from Potential Barrier Having Size Comparable with Wavelength

Plasma Wave Reflection from Potential Barrier Having Size Comparable with Wavelength

Computer simulation of the stimulation of electromagnetic vibrations of an open plasma resonator

In calculating microwaves - amplifiers and generators based on the emission of highly relativistic electronic beams in limited plasma, you have to face a number of difficulties, one of which is the correct setting of radiation conditions. Since there is no one-size-fits-all algorithm to overcome these challenges, you have to use a variety of simplistic assumptions and corresponding models. For example, plasma generators typically assumed that the width of the spectrum of vibrations generated was small and the central frequency corresponded to the frequency of accurate Cherenkov resonance. However, these assumptions were justified only for beams with currents of smaller maximum vacuum current. It was for such beams, using the method slowly- changing amplitude and introducing a constant ratio of plasma wave reflection from the radiating mouthpiece, it was possible to create a non-stationary theory of plasma microwave - a generator. However, the possibility of applying this approach is very limited, as it does not use a strict form of radiation conditions. This is due to the fact that known boundary conditions of radiation were developed to describe only established vibrational processes. Currently, there are various options for generalizing these boundary conditions for a non-stationary case, but all of them are not without certain shortcomings. One of the most successful variants of the radiation boundary conditions for the complete non-stationary system of Maxwell - Vlasova is, in our view, the unsteady analogue of the partial radiation conditions. However, the practical implementation of these conditions also faces serious mathematical difficulties. The question of the feasibity and effectiveness of these radiation conditions in relation to a specific electrodynamic system is being considered in this paper.

Plasma wave reflection from a boundary with specular accommodative boundary conditions

In the present work, linearized problem of plasma wave reflection from a boundary of a half-space is solved. Specular accommodative conditions of plasma wave reflection from the boundary are taken into consideration. Wave reflectance is found as function of the given parameters of the problem, and its dependence on the normal electron momentum accommodation coefficient is shown. Longwave limit of the solution is analyzed.

Plasma waves reflection from a boundary with specular accommodative boundary conditions

In the present work the linearized problem of plasma wave reflection from a boundary of a half-space is solved analytically. Specular accommodative conditions of plasma wave reflection from plasma boundary are taken into consideration. Wave reflectance is found as function of the given parameters of the problem, and its dependence on the normal electron momentum accommodation coefficient is shown by the authors. The case of resonance when the frequency of self-consistent electric field oscillations is close to the electron (Langmuir) plasma oscillations frequency, namely, the case of long-wave limit is analyzed in the present paper.

Reflection of plasma waves from a plane boundary

We state and analytically solve the linearized problem of the reflection of plasma waves from the half-space boundary in gas plasma for the first time. We consider mirror and diffusion boundary conditions and find the reflection coefficient as a function of the original problem parameters. We analyze the long-wave limit.

The influence of striction density perturbations on the excitation of plasma oscillations inside thermal inhomogeneities of plasma

In this paper, we continue our studies begun in [Izv. Vyssh. Uchebn. Zaved., Radiofiz.,41, No. 3, 270 (1998)].Calculating the coefficients and nonlinear phase shift in the equation for plasma-wave intensity introduced in the eralier paper, we have solved the problem of the influence of striction perturbations of the plasma density on the excitation of shortwave plasma oscillations by an electromagnetic wave; the above oscillations are captured in a volume of inhomogeneities, which are extended along the magnetic field and have reduced electron density that crosses the level of the upper-hybrid resonance. The dissipative processes of absorption and emission of plasma waves beyond the inhomogeneity are assumed to be weak. The variation of excitation and reflection of plasma waves from the resonance level due to deformation of the plasma- density profile is described. The band of effective generation of eigenmodes of captured oscillations as a function of the total wave-phase increment in an inhomogeneity is determined. The effect of penetration of the field of a high-power plasma wave into the non-transmittance region as a result of the striction expulsion of plasma is calculated. With allowance for the nonlinear phenomena in question, we estimated the heating of artificial inhomogeneities of thermal origin as a result of collisional absorption of the plasma oscillations excited in a volume of inhomogeneities under the action of a high-power radio wave.

KINETIC MODEL OF TONKS-DATTNER RESONANCES IN A POSITIVE COLUMN

Widely reported resonances in positive columns are described by a kinetic model in which electrons reflected at the sheath provide a plasma wave reflection mechanism which has been lacking in earlier fluid theories. Application of a weak magnetic field is shown experimentally to destroy the resonances when the gyro-radius falls below the dimension of the reflection zone.

Plasma Wave Reflection in Slowly Varying Media

Two mathematical formalisms are presented to describe wave reflection in a slowly varying spatially inhomogeneous thermal plasma described by the Vlasov equation. It is found that the transmitted wave, which is the Wentzel-Kramer-Brillouin solution, and the reflected wave, can be expressed in terms of the local dielectric properties of the medium. In a numerical example, it is shown that the intrinsic thermal properties of the plasma can supply reflection mechanisms that compete with the reflection coefficient predicted when the plasma is described by fluid equations.