Abstracts of papers for

Previous issue vol. 46, no. 3 (2005)

vol. 46, no. 4 (2005)

Next issue vol. 47, no. 1 (2006)

Contents of issue 4, vol. 46

1. R. Brojewski, B. Jakubiak, J. Jasiński: Dynamics of a 2L-baroclinic model of the troposphere. Part 2: Impact of the zonal drift on bifurcations in the model
2. E. Danicki: Plane-wave theory of interdigital transducers comprising multi-strip periodic cells working in Bragg regime
3. A. Ciarkowski, B. Atamaniuk: Electromagnetic diffraction by a moving half-plane
4. J. Sosnowski: The vortex dynamics in HTc superconductor in external magnetic field

R. Brojewski, B. Jakubiak, J. Jasiński: Dynamics of a 2L-baroclinic model of the troposphere. Part 2: Impact of the zonal drift on bifurcations in the model

The paper presents results of numerical analyses related with assessment of the impact of mean zonal drift in the troposphere on the properties of the dynamics of a simple two-layer model of the baroclinic troposphere. It was proved that the model dynamics is mainly influenced by zonally differentiated surface temperature. It causes numerous bifurcations. They are often Hopf bifurcations of the second kind during which tropospheric states quite distant from the states before the bifurcations are generated. It significantly influences the model predictability. The paper contributes to the assessment of applicability of hydrodynamic models to weather forecasting for periods longer than two weeks.

Contents

E. Danicki: Plane-wave theory of interdigital transducers comprising multi-strip periodic cells working in Bragg regime

Interdigital transducers of surface acoustic waves are periodic or nearly periodic systems of strips. In several applications they work in the Bragg regime to obtain strong surface wave Bragg reflections. This paper presents generalization of the spectral, full-wave theory to the case of transducers exploiting periodic cells comprising many strips of arbitrary width and positions within the cell. A novel method is applied to solve the dynamic boundary-value problem by means of the generalized electrostatic analysis. The generalization is useful for two purposes: for analysis of transducers having substantially aperiodic strips (by applying large cell periods with respect to the transducer length), and for analysis, in the frame of spectral theory, of unidirectional transducers exploiting cells comprising several different strips and certain interconnections between them within each cell. The theory yields full characterization of such transducers, including the surface wave dispersion characterized by stopband frequencies, and the transducer directionality.

Contents

A. Ciarkowski, B. Atamaniuk: Electromagnetic diffraction by a moving half-plane

A problem of electromagnetic (EM) plane wave diffraction by a moving half-plane in a free space is considered. It is shown that, unlike the stationary case, the shadow boundaries of the incident and reflected waves are not parallel to the propagation directions of those waves. Other diffraction phenomena reported earlier for objects with moving edges are also observed.

Contents

J. Sosnowski: The vortex dynamics in HTc superconductor in external magnetic field

The penetration of magnetic induction into HTc superconductors has been considered taking into account the layered structure of these materials. For magnetic field parallel to the planes a one-dimensional penetration has been considered, while in perpendicular magnetic field it is a two-dimensional problem. The flux creep equation has been considered, whose solution was confirmed by experimental data measured on an Y-Ba-Cu-O sample. The magnetic diffusion equation has been solved for a description of the magnetic induction profiles in an increasing external magnetic field. The dynamic anomalies of the current-voltage characteristics have been then predicted, in agreement with experimental observations. The model taking into account the influence of the vortex-pinning center interaction on the magnetic field dependence of the critical current, has been also applied successfully for description of the anomalies.

Contents