Table of contents

We investigate how the choice of the magnetization distribution inside a sample affects its interaction with an external electromagnetic field. Strong selectivity to the time-dependence of the external electromagnetic field arising for particular magnetizations suggests that it can be used for storage and ciphering of information. We propose a time-dependent Aharonov-Bohm like experiment in which the time-dependence of the interference picture is due to the time variation of the magnetic flux confined to the excluded region. The arising time-dependent interference picture may be viewed as a new channel for information transfer. Examples are given of current configurations generating static electric fields adequately described by an electric vector potential rather than by a scalar one.

The eigenfunctions of the recursion operator Φ with eigenvalue λ_i and the inverse of the recursion operator Φ_i ≡ Φ − λ_i for the Dym equation (DE) are obtained by means of the pseudopotentials or the isospectral functions of the isospectral problem. The symmetries and algebras of the DE are also given. Using some symmetry subalgebra of the DE, thirteen types of the significant similarity reductions are obtained by virtue of the classical Lie approach. For six types of reductions, the general solutions can be obtained by means of the Weierstrass elliptic function, Riemann's zeta function, Jacobi elliptic functions and the solutions of a Riccati equation implicitly. Three types of reductions can all be solved by means of the Painlevé II equation but with different independent arguments. Some types of nontravelling singular solitary waves exist for the Dym equation there are two types of nonsingular nontravelling solitary wave solutions for some suitable potentials.

In this work we present some general characteristics of inelastic interactions of 3 A GeV/c ⁷Li projectiles with emulsion nuclei. The mean free path is measured and found to agree with the different theoretical parameterizations. The multiplicity characteristics for interactions were studied and separated into (H), (CNO) and (AgBr) groups. The KNO type of scaling behavior of the multiplicity distribution is well satisfied by all target protons produced due to ⁷Li-Em and ⁷Li-AgBr interactions at 3 A GeV/c. Azimuthal correlations in angles between various types of charged secondary particles have been investigated.

A method of parametrization of interactions in the fine-structure of 3d-atoms is extended to the model space of configurations (nd + n's)^{N + 2} + Σ_i,jnd^{N + 2 − w_i − w_j}n_il_i^w_in_jl_j^w_j. It accounts for the first- as well as the second-order effects of the perturbation theory. The close analogy to the parametrization of the hyperfine structure interactions is shortly discussed, this can serve as a sensitive test for the quality of fine structure analysis.

A model of the ground state water molecule is formulated dynamically and studied by computer simulations. Excellent approximations of NMR determined bond angles and bond lengths are achieved through electron pairing and simulation of ice I.

We have calculated x-ray and UV spectra of Be-like Fe (Fe XXIII) ions in a collisional radiative model including all fine-structure transitions among the 2s², 2s2p, 2p², 2snl and 2pnl' levels where n = 3 and 4, adopting data for the collision strengths by Zhang and Sampson (1992) and by Sampson, Goett and Clark (1984). Some line intensity ratios can be used for temperature diagnostics. We show 5 ratios in the UV region and 9 ratios in the x-ray region as a function of electron temperature and density at 0.3 keV ≲ T_e ≲ 10 keV and n_e = 1 – 10²⁵ cm⁻³. The effect of cascade in these line ratios and in the level population densities are discused.

We have developed a model, l-dependent potential to describe the interaction of an electron with inert gas atoms, and Be, Mg, Zn, Cd, Hg, and their isoelectronic sequences. This potential is adjusted so as to produce bound states with experimental binding energies in isoelectronic sequences of Li I, Na I, K I, Rb I, Cs I and B I, Al I, Ga I, In I, Tl I, and extrapolated to get a potential for the interaction of an electron with inert gas atoms, and with Be, Mg, Zn, Cd, Hg. It provides reliable phase shifts and cross sections for e-inert gas atom, e-Be, e-Mg, e-Zn, e-Cd, e-Hg scattering. Particularly interesting are the signs of the scattering lengths, the changes in the signs of the s-wave phase shifts, and p-wave shape resonances at low energies.

Theoretical energy levels and oscillator strengths are reported for the 4d⁸5s–4d⁸5p, 4d⁸5p–4d⁸6s and 4d⁸5p–4d⁸5d transitions in Pd II. The relativistic Hartree-Fock (HFR) method combined with an optimization of electrostatic and spin-orbit parameters (radial energy integrals) based on the observed energy levels has been used for the calculations.

We have calculated spectra due to Kα line emission from aluminum Li-, Be-, B-, C-, N-, O- and F-like ions. The following atomic processes have been taken into account to model the population distribution of the upper levels of these transitions: dielectronic recombination, and inner-shell collisional excitation and deexcitation. From these processes, inner-shell excitation is the dominant populating process. We illustrate this result by calculating and displaying the Kα emission spectra of B- and C-like Al produced under different conditions. These results are relevant for the interpretation of Kα emission spectra generated by plasmas with hot electrons.

A parametric description of the 3d^N4p configurations in the IV to VI spectra of the iron sequence with orthogonal operators is reported. Compared to earlier calculations, deviations between calculated eigenvalues and experimental energies are reduced by an order of magnitude and approach experimental errors bars. The claim that the fits are physically meaningful is supported by the regular behaviour of the parameters among neighbouring ions and associated 3d^N cores, as well as by comparison with ab initio calculated values.

A self-consistent model of ideal magnetostriction is presented on a thermodynamic basis for the coupling between magnetostriction of ferromagnets and the behaviour of magnetization or induction curves (an anhysteretic approach is developed). The model is based on a rigorous adherence to the energy conservation law which is written in a characteristic differential form. The author employed an additional assumption concerning the presence of saturation effects to obtain a magnetic equation of state for some ferromagnetic materials. The coefficient κ is introduced for the coupling between magnetic and mechanical processes. A mechanical equation of state (the expression for magnetostriction) is derived using the thermodynamic Maxwell reciprocity relations. The separation of strains into magnetic and purely mechanical parts comes about as a logical consequence of the self-consistent approach. The conclusion is made that the well-known Villari and Joule effects can be treated as a coupling between magnetic and mechanical processes within the framework of an invariant coupling coefficient. The behaviour of the magnetostrictional modulus of elasticity for ferromagnetic materials is discussed and, as is shown, it takes on negative values within a certain range of the magnetic field and mechanical stress. The last Section of the paper concentrates briefly on the strength problems. Modeling results are in a good agreement with experiments.

The electrohydrodynamic stability of a streaming liquid (density ρ) jet, of radius R, under the influence of self gravitating force is studied. The system is stresses by a longitudinal electric field of intensity E₀. The general dispersion relation is derived, for axisymmetric perturbations, and studied analytically and numerically. The longitudinal electric field has a stabilizing influence. The axial flow has a strongly destabilizing effect. It is shown that the largest domain of instability is fastly shrinking with increasing (E₀/E_G) values, E_G = (4πGR²ρ²)^1/2 where G is the gravitational constant. Some reported works are recovered as limiting cases from the present results.

Scattered time-dependent intensities for a dielectric microsphere illuminated with a very short pulsed plane wave are calculated. The incident pulse is considered to be a rectangular or Gaussian shaped pulse. The results are obtained for a sphere at a resonant mode. The frequency spectrum of the scattered field at a point is calculated using the incident field spectrum and the transfer function at that point. The transfer function at any frequency of the sphere at a space point is calculated using the T matrix method. The inverse Fourier transform of the frequency spectrum is used to calculate the time-dependence of the electric field. The scattered intensities are calculated for pulses of durations (~10 ps) smaller than the resonant lifetime. The computer codes are capable to calculate the scattered intensity of a shorter pulse but depend on the capacity and speed of the computer system. The main factors that affect the behavior of the scattered pulse are the incident pulse spectrum (or duration) and the lineshape of the resonant mode of the sphere.

A rigorous investigation has been made on the modification of the dispersion properties of electromagnetic waves in a hot dusty plasma in the presence of a homogeneous external magnetic field. The Vlasov equation has been employed to find the response of the magnetized plasma particles where the dust grains form a static background of highly charged and massive centers having certain correlation. As an example, we derive the modified dispersion relation of the low frequency electromagnetic wave propagating perpendicular to the external magnetic field, i.e., the magnetosonic wave in the dusty plasma. We find important modifications in the dispersion relation and a finite damping of the usually undamped magnetosonic wave due to the presence of the dust. The modification of the dispersion properties and the new source of damping depend upon dust perturbation parameters, temperature, external magnetic field and the dust correlation length.

The maximum electric field in bursts of plasma frequency oscillations produced in an anode double layer was measured by observing deflections of a probe electron beam. It is found that the electric field is larger than the threshold field required for strong turbulence associated with caviton formation and Langmuir soliton collapse.

Energy spectra of two-dimensional two electron quantum dots in transverse magnetic field is calculated by numerical diagonalizing of the Hamiltonian on the basis of single-particle eigenfunctions. A model of parabolic lateral potential is used. Spectra of these quantum dots are studied in a wide range of confining potential parameters and magnetic fields.

The absorption reflection and luminescence excitation spectra, as well as the x-ray excited stationary and thermostimulated luminescence spectra of BBO crystals have been measured over a wide spectral (4–30 eV) and temperature (8–300 K) range. The experimental data show that the formation of the absorption edge of the crystal is strongly affected by excitonic-type excitations.