Abstracts of papers for

Previous issue vol. 44, no. 4 (2003)

vol. 45, no. 1 (2004)

Next issue vol. 45, no. 2 (2004)

Contents of issue 1, vol. 45

1. J. Badziak, P. Parys, J. Wołowski, E. Woryna: Studies of ion fluxes emitted from picosecond and nanosecond laser-produced plasmas
2. J. Sosnowski: Influence of the dynamic vortex-pinning center interaction on the critical current in the layered HT_C superconductors
3. K. Jach, R. Świerczyński, Z. Wilk: Modelling of perforation process of wellbore pipes of geological wells using shaped charges
4. F. Conforto, S. Giambò, G. Valenti: Transverse diffraction of weakly nonlinear waves for a first order quasi-linear system involving source-like terms
5. H. Ymeri, B. Nauwelaers, K. Maex: Simple modeling approach for line impedance of on-chip CMOS interconnects
6. A. Wiśniewski: Modelling of armours penetration with armour piercing fin stabilized discarting sabot projectiles

J. Badziak, P. Parys, J. Wołowski, E. Woryna: Studies of ion fluxes emitted from picosecond and nanosecond laser-produced plasmas

Energetic ions emitted from plasmas produced by the interaction of intense laser pulses with solid targets are currently a subject of growing interest due to the possibility of unique applications in accelerator technology, nuclear physics, material science and medicine. Depending on the kind of application, different parameters of the ion fluxes are required, and various conditions of laser-target interaction must be considered. In this paper, selected results of our recent studies of ion emission from plasmas produced by laser pulses of duration from ~1 ps to ~1ns and of intensities from 10¹⁰ W/cm² to 10¹⁷ W/cm² are reviewed. The characteristics of both heavy ion fluxes emitted from massive high-Z targets and proton beams generated from thin foil targets of various structures are presented. Some basic properties of ion fluxes produced in various experimental conditions are discussed. The effect of external magnetic field on the ion emission is demonstrated.

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J. Sosnowski: Influence of the dynamic vortex-pinning center interaction on the critical current in the layered HT_C superconductors

Interaction of the magnetic vortices in the layered structure of the high-temperature oxide superconductors with the pinning centers created by the heavy ions irradiation is investigated. The influence of this dynamic interaction on the current-voltage characteristics and critical current of the Bi:2212 high temperature superconductor is considered. The results of research allowed to determine the current-voltage characteristics dependence on the heavy ions irradiation dose, as a function of temperature and magnetic field and to predict the anisotropy of the critical current in this material, depending on the magnetic field direction.

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K. Jach, R. Świerczyński, Z. Wilk: Modelling of perforation process of wellbore pipes of geological wells using shaped charges

The paper shows the results of computer simulation of holes punching in steel pipes of oil-gas wells using cumulative charges. The holes make possible quick re-circulation of an exploited medium and renewal of oil-field development. Because of the conditions in a well (large depth, high pressure), limited place for the charges, and requirement of punching of the holes with precisely determined diameter and depth, specially designed charges must be applied. They have to generate a punching element (puncher) that is something between shaped charge jet and explosively formed projectile (EFP). Analyses of punching abilities of such charges (especially in a complex system of wellbore pipes and layers of sand, borehole fluid, and air filling and separating them) are possible only when the methods of computer physics are applied. The results of computer simulation based on a new version of free particle method [11, 14] are given and their comparison with experimental results is presented. New version of a free particle method makes possible computer simulation of the problem with very complex initial-boundary conditions.

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F. Conforto, S. Giambò, G. Valenti: Transverse diffraction of weakly nonlinear waves for a first order quasi-linear system involving source-like terms

Making use of the ray theory and the method of asymptotic expansion of multiple scales, a study of the diffraction of weakly nonlinear waves in a direction transverse to the rays, through media described by dissipative or dispersive hyperbolic systems, is proposed. It is shown that the wave amplitude satisfies a generalized Zabolotskaya-Khokhlov equation in the dissipative case, or a generalized Kadomtsev-Petviashvili equation in the dispersive case. Moreover, plane, cylindrical and spherical waves are also investigated. The present approach is used to study wave diffraction in a heat-conducting fluid.

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H. Ymeri, B. Nauwelaers, K. Maex: Simple modeling approach for line impedance of on-chip CMOS interconnects

Simple and accurate closed-form model enabling to calculate frequency-dependent distributed inductance and associated distributed series resistance per-unit-length of single on-chip interconnects on a lossy silicon substrate is presented. The closed-form formulas for the frequency-dependent series impedance parameters are obtained using a closed-form integration method and the vector magnetic potential equation. The proposed frequency-dependent inductance L(ω) and resistance R(ω) per-unit-length formulas are shown to be in good agreement with the electromagnetic solutions.

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A. Wiśniewski: Modelling of armours penetration with armour piercing fin stabilized discarting sabot projectiles

Using the "free points" method, a simulation of 125 mm subcalibre projectile penetration in different armours - steel, aluminium-steel, and composite multilayered (ceramic-steel), was done. For this simulation, parameters and material constants, for projectile material and different layers in penetrated armours, were found. Results of simulation were compared with results of armours firing with such projectiles.

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