Self-Interaction of Electron Plasma Waves in a Planar Plasma-Filled Waveguide

Nonlinear behaviour of electron plasma waves propagating in a planar plasma-loaded waveguide immersed in an infinite magnetic field is analysed including finite temperature and mobile ion effects. It is shown that the wave becomes modulationally unstable if the wavenumber exceeds certain critical value K_c, which decreases with rise of temperature. The growth rate of instability is calculated and is found to increase with the rise of temperature.     

Linear Theory of Free Electron Laser with a Plasma-Loaded Cylindrical Waveguide

The dispersion characteristics of plasma–loaded free-electron laser has been analyzed using linear fluid model. The device under consideration consists of the cylindrical metallic waveguide, completely filled with background plasma and a relativistic electron beam which passes through a helical wiggler magnetic field. The result predicts that reasonable plasma density tends to improve the growth rate of the low-frequency optical wave of FEL and causes an shiftup in the operating frequency, However it has little effect on the growth rate of the high-frequency wave. In the plasma–loaded FEL, for the FEL oscillator, it may be tuned by varying the plasma density; and for the FEL amplifier, the wider frequency bandwidth is gained. A critical density n ^c _p for the background plasma density is found.     

Interaction of an Electron Beam with Electromagnetic Waves in a Rectangular Plasma Waveguide

We study the interaction of a rectilinear nonrelativistic electron beam with a solid-state plasma in a rectangular metal waveguide, as well as wave processes in a plasma waveguide of rectangular cross section in the absence of an electron beam. It is shown that in such a system, space-charge waves of an electron beam, which propagate along a semiconductor boundary, become unstable in a wide frequency band.__________Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 3, pp. 219–227, March 2005.     

Solitary Leaking Waves in a Plasma Slab

Considering a plasma slab we show that electromagnetic field perturbations, which within linear theory are identified as leaking modes, can appear in the form of solitary waves that propagate along the slab.     

Electron-Acoustic Solitary Waves in a Two-Electron Temperature Plasma

Using fluid model the propagation of the solitary wave has been analytically investigated in a plasma of two-temperature electrons and ions. It is found that under suitable conditions ion-acoustic solitons of compressive nature and electron-acoustic solitons of rare-factive nature can exist.     

Solitary Waves in Relativistic Electromagnetic Plasma

Solitary waves in relativistic electromagnetic plasmas are obtained numerically. The longitudinal momentum of electrons has been taken into account in the problem. It is found that in the moving frame with electromagnetic field propagating the solitary waves can exist in both cases, where the vector potential frequency is larger or smaller than the plasma characteristic frequency.     

Relativistic Electromagnetic Solitary Wave in a Cylindrical Magnetized Plasma

In the presence of an applied static and uniform magnetic field, a cylindrical Kadomtsev-Petviashivili equation is derived for a relativistic electromagnetic solitary wave propagating in collisionless plasma consisting electrons, positrons, and ions in the case of weak relativistic limit. This equation is solved in a stationary frame to obtain explicit expression for the velocity, amplitude and width of solitons. The amplitude of the solitary wave has a maximum value at a critical αc of the ratio of the ion equilibrium density to the electron one, and it increases as the applied magnetic field becomes larger.     

Nonlinear Dynamics of Cylindrical Plasma Waves

The nonlinear dynamics of Langmuir cylindrical waves in a collisionless plasma is studied. The possibility of energy transformation in such waves is considered.     

Oblique Electron Thermal Waves in a Magnetized Plasma

Propagations of an oblique electron thermal mode under the electron plasma frequency without boundary effects are investigated experimentally and theoretically in a magnetized plasma. The phase, ray, and group velocity surfaces of the electron thermal mode are obtained in a polar coordinate. The experimental observation of the electron mode radiated from a point source is found to be in fair accord with the theoretical wave fronts which are obtained from the ray velocity surface. Wave fronts and ray trajectories of an oblique electron thermal mode radiated from a point source are numerically obtained in an inhomogeneous magnetized plasma with a use of an electrostatic kinetic theory. The spatial numerical results are indicated mainly below the electron plasma and cyclotron frequencies. Reflections of the mode in the plasma density lower than the electron plasma frequency are made clear numerically.     

Nonplanar Ion Acoustic Solitary Waves in a Two-Electron Temperature Plasma

Linear and non-linear properties of ion acoustic wave （IAW） propagating in a two-electron temperature plasma are investigated from both analytical and numerical perspectives by employing the fluid theory. A one-dimensional modified Korteweg de Vries equation is derived for the IAW using the reductive perturbative technique in a nonplanar geometry. It is observed that the ion acoustic soliton in a two-temperature plasma admits rarefactive （dip like） solitons. In the limit that the cold electron population goes to zero, it is observed that the ion acoustic soliton yields compressive （hump like） solitons. The variation of the ion acoustic soliton with different plasma parameters is also shown. The present investigation may be beneficial to explain some aspects of ion acoustic rarefactive solitary structures observed in space environments where two-electron temperature plasmas have been observed.     

Nonplanar Electrostatic Solitary Waves in a Relativistic Degenerate Dense Plasma

By employing the reductive perturbation technique, the propagation of cylindrical and spherical ion acoustic solitary waves is studied in an unmagnetized dense relativistic plasma, consisting of relativistically degenerate electrons and cold fluid ions. A modified Korteweg-de-Vries equation is derived and its numerical solutions have been analyzed to identify the basic features of electrostatic solitary structures that may form in such a degenerate Fermi plasma. Different degrees of relativistic electron degeneracy are discussed and compared. It is found that increasing number density leads to decrease the amplitude the width of the ion acoustic solitary wave in both the cylindrical and spherical geometries. The relevance of the work to the compact astrophysical objects, particularly white dwarfs is pointed out.     

Fast and Slow Mode Solitary Waves in a Five-Component Plasma

We have investigated fast- and slow-mode solitary profiles in a five-component plasma consisting of positively and negatively charged pair ions, hydrogen ions, and hotter and colder electrons. Of these, the heavier ions and colder photoelectrons are of cometary origin while the other components are of solar origin; the electrons are described by kappa distributions. The Zakharov-Kuznetsov (ZK) equation is derived, and solutions for fast- and slow-mode solitary structures are plotted for parameters relevant to comet Halley. We found that the presence of hydrogen ions determines the polarity of the fast- and slow-mode solitary structures. Also, variations of equilibrium number density of hydrogen ions and charge numbers on the heavier pair ions act differently on the fast- and slow-mode solitary structures. The addition of hydrogen ions significantly affects the amplitude of the solitary structures for the fast mode. Further, the cyclotron frequency of the lighter and heavier ions has a noticeable effect on the width of the solitary waves.     

Time-Dependent Cylindrical and Spherical Solitary Structures and Double Layers of Dust Ion-Acoustic Waves in Ultra-Relativistic Dense Plasma

Cylindrical and spherical (nonplanar) solitary waves (SWs) and double layers (DLs) in a multi-ion plasma system (containing inertial positively as well as negatively charged ions, non-inertial degenerate electrons, and negatively charged static dust) are studied by employing the standard reductive perturbation method. The modified Gardner (MG) equation describing the nonlinear propagation of the dust ion-acoustic (DIA) waves is derived, and its nonplanar SWs and DLs solutions are numerically analyzed. The parametric regimes for the existence of SWs, which are associated with both positive and negative potential, and DLs which are associated with negative potential, are obtained. The basic features of nonplanar DIA SWs, and DLs, which are found to be different from planar ones, are also identified.     

Diffraction of Electromagnetic Waves by an Anisotropic Cylindrical Inhomogeneity in a Planar Waveguide

We consider diffraction of electromagnetic waves by an anisotropic cylindrical inhomogeneity located in a planar waveguide with perfectly conducting walls. Anisotropy is allowed for by using the uniaxial-crystal approximation. A rigorous analytical solution is represented in the form of double sums over eigenfunctions of a planar waveguide with perfectly conducting walls and azimuthal eigenfunctions of a cylinder. Different components of the intensity of the electric field scatttered by an anisotropic inhomogeneity are numerically calculated. The influence of the anisotropy and sizes of the inhomogeneity on the scattered field is analyzed. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 7, pp. 605–615, July 2005.     

Solitary Surface Waves on a Plasma Confined by External Radiation

We consider the nonlinear surface deformation of a plasma which is confined by external fields. It then turns out that a perturbation of the plasma-vacuum boundary can propagate as a solitary wave with a velocity that depends on the external radiation intensity.     

超短强激光脉冲驱动等离子体波加速电子方案

随着超短脉冲激光技术的发展, 人们可以在台面尺度获得光强超过10¹⁸W/cm²、脉宽小于100fs的超短脉冲激光.超短脉冲激光很容易把静止的电子加速到兆电子伏的能量. 而更重要的是超短激光脉冲可以通过其有质动力激发大振幅的等离子体波(称为激光尾波场), 后者可以在毫米空间尺度把电子加速到上百兆电子伏的能量.文章将介绍激光尾波场加速电子的物理机制和方案、这个领域的最新进展、以及目前存在的问题.     

Electromagnetic Waves in Waveguide Partially Filled with Semiconductor Plasma

The dispersion of electromagnetic waves in waveguides partially filled with semiconductor plasma is investigated for unmagnetized and for strongly magnetized plasma. The effects which may be useful for the plasma electronics are found: In such waveguides there exist a large number of slow waves with typical frequencies ω ≈ ωP/√?_L. The filling at which the different modes at fixed phase velocity are maximum separated in wavelength is found. The thickness of the semiconductor layer at which this effect arises is about hundred micrometers and depends on the crystals' type. In addition to this, in strongly magnetized semiconductor plasma the maximum frequency separation of the typical plasma waves is found at fixed filling. Is it shown that in such systems there exist many surface waves which are of the slow wave type. In the case of strongly magnetized plasma coupling between nonsymmetrical EH- and HE- modes is shown to exist.     

Theory of Weak Modified Electron Acoustic Double Layers and Solitary Waves in Presence of Negative Ions

We have studied the analytic solutions for modified electron acoustic double layers and solitary waves in a four component plasma system viz. two electrons and two ions, one positive and the other negative. It has been shown that DL solution does not exist when the temperatures of the free and the trapped particles are considered to be same for all the free species. On the other hand, DL solutions are found to exist when the effects of the reflected electrons (hot) are considered. The velocity and thickness of the DL have been valculated.