Electron Spectrum of Nonlinear Cold Emission from a Metal under the Action of a Laser Shot

The nonlinear emission of electrons from a metal under the action of a femtosecond moderate-intensity laser pulse (laser shot) has been studied. A theoretical model of the process has been constructed based on the 1D nonstationary Schrödinger equation in the vacuum half-space with given boundary conditions for the electron wavefunction. This equation has been solved using the Laplace transformation. It has been assumed that the states of free electrons in a metal, which are described by the Sommerfeld theory of metals, are insignificantly influenced by the laser field. The energy spectrum of emitted electrons has been obtained, and its dependence on the parameters of the lased shot has been found. The calculated spectrum of nonlinear electron emission from a tungsten nanotip under the action of a 6.5-fs-long laser shot generating a field of 9.26 V/nm agrees with the experimental data.     

Confinement of an Electron in an Image Potential and an External Electrostatic Field

The quasi-classical approximation is used to determine the positions of the classical turning points upon motion of an electron that is bound by an image field and a constant homogeneous electric field of the same direction. Power expansions of the coordinates of the turning points in a wide range of electron energies and field strengths are obtained. The mechanism of one-dimensional confinement of an electron, which determines a completely discrete spectrum of states, is described. The dependence of the spatial width of the confinement region on the field strength and electron energy is determined. The dependences of the electron energy in different states on the external field strength are calculated numerically. Quasi-classical quantization is performed, and the dependence of the electron energy on the width of the confinement region is determined. The energy interval of a maximum density of electron states is found, which is determined by the dependence of the width of the confinement region on the electric field strength.     

Multiphoton Polarization Bremsstrahlung Effect

Based on the many-particle theory, a general approach to the stimulated polarization effects in a strong periodic field is formulated. A relation to the perturbation theory is demonstrated and forms of the effective polarization potentials for isolated atoms and ions and for ions in plasma are presented. The state of the art of the theory of stimulated polarization bremsstrahlung effect is analyzed, and some prospects for further experimental and analytical investigations are outlined.     

Description of diffraction and focusing of ultrashort pulses on the basis of a nonstationary Kirchhoff-Sommerfeld method

The scalar problem of the propagation of a plane-wave pulse behind a diaphragm is solved. The calculation is performed on the basis of the nonstationary Kirchhoff-Sommerfeld integral and decomposition of the pulse in terms of wavelets. Two types of diaphragms, circular and square, are studied. The propagation of a pulse under focusing conditions is calculated. The Green’s function of the diffraction problem for a circular opening with and without aberration-free focusing is constructed.     

Quasienergy basis for multielectron system in a strong laser field

The second-quantization procedure is performed in the basis of quasienergy states, and an expression is obtained for the Green's function of a finite Fermi system. A nonstationary effective potential is constructed in the Hartree-Fock and local-density approximations, and possibilities for using it are discussed.Voronezh Constructional Engineering Institute. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 97, No. 1, pp. 121–132, October, 1993.     

Influence of the Particle Density Distribution on the Optical Resonance in a Fractal Cluster

Based on the equation of a self-consistent field in a fractal cluster, solutions are derived that characterize the laser field amplification as a function of the particle density distribution in the cluster. The influence of the specific features of the particle density distribution in the cluster on the resonance position is established.     

Predicting the endurance of ceramics from the results of verification tests

Mechanics of Composite Materials -     

Interference in the photodecomposition of negative atomic hydrogen ions in an electric field

The quantum interference of electron waves in the photodecomposition of negative hydrogen ions in an external uniform electric field is examined. The structure of the photodetachment amplitudes is discussed. A simple analytic expression for the electron flux distribution is derived. Finally, it is shown that the structure of the electron flux is affected by the angular dependence of the wave function. Zh. éksp. Teor. Fiz. 112, 1574–1583 (November 1997)     

Scattering of relativistic electrons in a strong electromagnetic field with allowance for the internal dynamics of the target

Stimulated bremsstrahlung of relativistic electrons in a strong electromagnetic field is considered. Polarization of the target in the external field, and also its excitation are taken into account. Expressions are obtained for the differential cross section of the process in a field of linear or circular polarization.Voronezh State University. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 95, No. 3, pp. 418–426, June, 1993.