Results 1 - 10 of 177
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[en] Complete text of publication follows. By using Maxwell equations and the nonlinear dielectric permittivity, the electric and magnetic field profiles along with the achieves density profiles in plasma with and without the ramped density are investigated. It is found that the electromagnetic fields are deviated from its normal sinusoidal profile and the wavelength of electric and magnetic field oscillations increases in comparison to the uniform underdense plasma. The effect of the weakly relativistic ponderomotive force generated by intense laser pulses in the underdense plasma with initial density ramp and temperature variations is studied. It is noticed that ponderomotive force modifies the electron density distribution and the steepening of the plasma density increases in the presence of the electron density with ramp profile.
[en] Complete text of publication follows. The ceramic which has a complex permittivity can absorb electromagnetic energy easily and be heated quickly. In this work, the heating of a ceramic cylinder by the Gaussian electromagnetic beam in two dimensions is investigated and the heat equation is solved. It is shown that this electromagnetic beam with Gaussian profile can heat ceramic sample better than the plane electromagnetic wave. Moreover, the effects of some important physical factors such as the permittivity of ceramic, the incident wave intensity and the spot size of the Gaussian beam on the heat transfer within the sample are studied. Also, comparing the effect of Gaussian electromagnetic beam on ceramics Al2O3 and, it is shown that Al2O3 ceramic is heated more intensively than ZnO ceramic.
[en] Complete text of publication follows. In this work it is shown that the electrons can be trapped and accelerated to the higher energies by two pulses in comparing to the single laser pulse with the same energy. A detailed analytical study of wakefield amplification making use of two laser pulses copropagating one behind the other, with a fixed time between them is presented. Three basic pulses in the shape of rectangular, Gaussian and sinusoidal are considered. It is found that when the first of the two laser pulses is rectangular and the second pulse is sinusoidal the produced wake field is maximum.
[en] Complete text of publication follows. We present the simulations of absorption of femtosecond laser pulses in copper using modified 1D Lagrangian ERA hydrocode enabling to model short-laser-pulse absorption, heat conduction, and plasma dynamics. Numerical modeling involved thermodynamic functions calculated by using first-principles Full-Potential Linearized Maffin-Tin Orbitals method (FP-LMTO) and chemical model of dense plasma utilizing superconfiguration approach. The results of simulations are compared to experimental and other theoretical data. Acknowledgements. The work has been supported in part by the International Science and Technology Center under the project no. 3755.
[en] Complete text of publication follows. Pulsed laser deposition method for producing thin films is investigated. This deposition method include several stages such as absorption of the laser beam in the target material, evaporation of the material producing plume of atoms or molecules, strong interaction of the laser beam with the plumb to produced plasmas, and finally deposition of atoms or molecules on the substrate surface. The growth of the thin film in the initial stage is simulated using Monte Carlo method. Our simulation indicated that by decreasing the duration of the pulse together with the decrease in laser energy, the thin film growth is steady so that the uniform and homogeneous layer is produced.
[en] Complete text of publication follows. The recently launched HiPER (High Power laser Energy Research facility) project is a European initiative to offer a credible way to demonstrate the possibility of opening up Inertial Fusion Energy as a commercial process for energy generation. One baseline target design includes cone geometries and there are significant technical and scientific challenges in the production of these cones to the required specification in the required numbers for the facility. There are also a large number of research projects that are investigating cone performance and are re-designing the cone to have novel features and specifications. We review the production of a number of different geometries and also the ability to mass produce such items.
[en] Complete text of publication follows. The present paper investigates the relativistic self-focusing of elliptical laser beam in underdense plasma and its effect on plasma wave and second harmonic generation. When intense laser beam interacts with plasma, then transverse intensity gradient is established on account of redistribution of carriers. This transverse intensity gradients results in generation of plasma wave and pump wave frequency. The generated plasma wave, in turn, interacts with the input laser beam and leads to generation of a second harmonic. Effect of relativistic self-focusing on the amplitude of plasma wave and second harmonic yield are also analyzed.
[en] Complete text of publication follows. Based on the gradient optimization method a useful approach for dissociation of the methane molecule is introduced. This analytical model produces an optimized two tailored rectangular laser pulses which dissociates the molecular ion CH4+ with maximum probability of 1. In this approach the field assisted dissociation is used by a semi-classical view. It is assumed that only the selective dissociative bond is in direction of the laser electric field are effective. Saturation is found for dissociation of the mentioned molecular bond, where the first pulse should have higher intensity than the second pulse. In addition to that, the sensitivity of the dissociation probability to the initial bond length and the control of the desired product channel by variation of the laser intensity and its duration of laser field is presented.
[en] The ECLIM conferences on the field of high intensity laser-matter interactions. In this year has the 50th anniversary of Maiman's first laser. ECLIM is a conference for all types of laser-matter interactions, especially for those occurring at high power. New lasers, new ideas are traditionally welcome. Applications as inertial fusion energy have been the driving force in the last decades towards increasing laser intensity, and toward the discovery of new, nonlinear interactions. This time the organizers want to open the doors even broader toward short-pulse laser-plasma interactions and attophysics, organizing even special session for the Extreme Light Infrastructure (ELI). ECLIM is this time hosted the first time in Hungary, one of the sites of the future's great undertaking, the ELI laser. (S.I.)
[en] Complete text of publication follows. The results of the investigations in the shock compressibility of materials on the 'Luch' facility are presented. The experiments have been performed with impedance mismatch technique applying. The output non-uniformity of the shocks achieved < 10 ps and inaccuracy of their velocity measuring < 3%. The pressures to 30 Mbars were developed in lead and till 50 Mbars with applying of the special-constructed targets for hydrodynamic pressure increasing. Results on the materials shock compressibility have been obtained that accord well with the test results shown on hydrodynamic stands. The work was performed in part under the sponsorship of the RFFI (grants No. 09-02-12157-ofi-m and No. 09-02-97089-r povolzh'ye-a), and grant of the President of the RF to leading scientific schools No. 65192.2010.2.