[en] The possibility of recurrence of the unique sporadic phenomenon - polar-cap absorption (PCA) - according to the full set of events for 1938-1986 is investigated. Repetition periods of PCA during 26-27 days and 32-33 days are detected by the method of time diagrams

[en] Analytical techniques have been utilized to obtain the radiation attenuation of nuclear power sources. This calculation was extended to cylindrical source geometry and results were computed by means of a computer program. The self-attenuation parameter of an annular fuel source is evaluated by analytical technique. The self-shielding parameter of a solid cylindrical source when the inner radius is allowed to approach zero is evaluated

No abstract available

No abstract available

[en] The two-dimensional resonance absorption problem is considered for a wave incident obliquely upon an inhomogeneous plasma with a linear density gradient perturbed by random irregularities which are modulated in the direction perpendicular to both the plasma background density gradient and to the magnetic component of the incident wave. The net coefficient of plasma reflectivity is obtained in the form of a sum of the regular coefficient of reflectivity and the coefficient of anomalous reflectivity. The latter is due to conversion of coherent light into incoherent light by scattering off the random plasma density irregularities

[en] When an intense electromagnetic wave is incident obliquely on a sharply bounded overdense plasma, strong energy absorption can be accounted for by the electrons that are dragged into the vacuum and sent back into the plasma with velocities v≅v/sub osc/. This mechanism is more efficient than usual resonant absorption for v/sub osc//ω>L, with L being the density gradient length. In the very high-intensity CO₂-laser--target interaction, this mechanism may account for most of the energy absorption

[en] The paper is concerned with formation of a small-scale structure near the plasma resonance caused by an electromagnetic field penetrating into plasma. It is assumed that the electron density depends only on the square of electric field amplitude (E)². Also considered are condition when the field in the plasma is similar in structure to the field of an ordinary wave and in a linear approximation there is no interaction with an E-wave which in this case is in the resonance. It is shown, assuming that the external magnetic field is relatively small, that the small-scale structure is formed at (E)² > > Esub(cr)² (Esub(cr)² approximately νsub(e)/ω)). The electromagnetic field energy dissipation occurring therewith is of a universal nature and does not depend either on the value of νsub(e)/ω or on the particular type of the nonlinearity under consideration

[en] The nonlinear phenomena is the plasma resonance region are shown to cause the suppression of the surface wave damping in a semi-bounded plasma with a transition layer. (author)

[en] An iterative method is developed to solve the neutron slowing-down equation in an infinite homogeneous media. It is based on an evaluation of the collision kernel by an iterative scheme. The results are in good agreement with these obtained using the SECOL code. The convergence is found to be rapid. For the same calculation the iterative method requires only one-quarter of the SECOL computation time. The method is generalized to fine structure and slowing down equations with many resonant nuclides. Optimization of the iterative scheme initialization has allowed us to reduce the number of iterations by half. The iterative method is applied to calculate the resonance escape probability and to study dilution and temperature effects on resonance absorption distribution. An approximate expression is proposed to represent the resonance effect integral dependence on both dilution and temperature with a relative error of less than 0.09%. (Author)

[en] The study of microstructure-property relationships is a defining concept in the field of materials science and engineering. Despite the paramount importance of microstructure to the field a rigorous systematic framework for the description of structural variance between samples of materials with the same processing history and between different materials classes has yet to be adopted. Here the authors utilize the formalism of stochastic processes to develop a statistical definition of microstructure and develop measures of structural variance in terms of the measured variance of estimators of higher order probability distributions. Principal component analysis (PCA) of higher order distributions is used to produce visualization of the space spanned by an ensemble of microstructure realizations and for quantification of the structural variance within the ensemble. The structural variance is correlated with the variance in properties and structure/property maps are produced in the PCA space.