A double layer a-CN/TiAlN coating deposited on ASP30 steel substrate was irradiated by femtosecond laser and surface modification effects were observed. Moderate laser intensities used were in the range of 1014–1013 W/cm2, while the total thickness of double layer coating was 4.8 µm (a-CN = 0.6 and TiAlN = 4.2 µm). Laser-induced changes of the surface showed dependence on laser intensity and number of accumulated pulses. Irradiations at the highest intensity resulted in preservation of one or both layers up to 10 pulses, while at lower intensity (1013 W/cm2) a-CN layer is removed after several pulses and TiAlN is preserved up to 50 pulses. Evaluated damage threshold of the target was 0.49 J/cm2. Lower laser intensity irradiation produced periodic surface structures (LIPSS) over the entire irradiated spot with periodicity of ~700 nm, almost in agreement with the laser wavelength used. Irradiations carried out at the highest laser intensity (1014 W/cm2) and laser pulse count of ≥50 resulted in the creation of crater like damages with depth up to 20 µm. Craters were conically shaped, implying intensive processes which took place at the surface. Generation of LIPSS as well as craters can be of great interest for contemporary technologies.

An investigation into the feasibility of using a laser-generated plasma source of soft X rays as a laboratory based instrument for biological imaging and microlithography is presented. A preliminary characterization of the source has been carried out with carbon, copper and aluminum targets with specific interest in generating a monochromatic source of soft X rays in the ‘water window’. Measurements of X-ray production with respect to angular distribution, effects of cratering and different focusing conditions are reported. Initial conclusions on the optimization of the source for use in biological imaging are drawn.

A self-consistent model for the beamline of a light ion beam fusion reactor is presented. Code calculations for the region from the end of the Magnetically Insulated Vacuum Transmission Line (MITL) entering the ion diode to the energy output from fusion reactions in the pellet fuel are described. The design utilises state-of-the-art pulsed power and a concept for repetitive operation of a pinch reflex diode. Deuterium beams are launched at 6·3 MV and are transmitted through preionized channels. Overall energy transfer efficiency from electrical source to pellet is 20%. The principal developments required are beam brightness, which scales from present day experiments, and repetitive diodes.

We propose a focusing mechanism of high-energy ions by an electron cloud produced by a laser interaction with slab plasma. In our 2.5-dimensional (2.5D) particle-in-cell simulations, the laser intensity is 2 × 1020 W/cm2, the laser wavelength λ is 1.053 μm, and the laser spot size is 2.5λ. When the high intensity laser irradiates slab plasma, electrons are accelerated, oscillate around the plasma and produce the electron cloud locally at the sides of the plasma. Because the electrons are localized transversely, a static electric potential is formed to focus ions and at the same time the ions are accelerated longitudinally. Though the longitudinal ion acceleration has been studied well, the ion focusing effect is reported for the first time in this paper. In our calculations, the maximum energy and intensity of the protons are 8.61 MeV and 1.89 × 1017 W/cm2, and the diameter of the proton bunch accelerated are focused to 71.2% of its initial size.

The paper presents the results of the analysis of the influence of curvature of the electrons trajectory in the anode–cathode gap of an ion diode on the diode impedance and evaluation of applicability of the one-dimensional (1D) Child–Langmuir (CL) ratio for calculation of the electron current. Investigations of an ion diode with a graphite anode in self-magnetic insulation mode were carried out. Experiments were performed on the TEMP-4M ion accelerator set in a double pulse mode, with the first negative pulse (150–200 kV, 400–600 ns) followed by the second positive pulse (250–300 kV, 150 ns). The result of this study is that we have determined the boundary conditions for the applicability of 1D CL ratio for calculation of the electron current in the ion diode. It was found that the deviation of the diode current–voltage characteristics from CL ratio will be observed only with a significant change in the acceleration voltage during electron drift or when the electron drift time exceeds the transit time of ions.

We study strongly correlated plasmas far from equilibrium with the ultimate aim of describing the cooling of heavy ion beams by electrons. With the help of molecular dynamics (MD) computer simulations, we conclude that the relaxation of a two-component plasma depends strongly upon the preparation of the initial configuration. If the initial data have no intercomponent correlations, such will build up during the evolution so that the intercomponent potential energy decreases while the kinetic energy increases. These effects become more pronounced for strongly coupled plasmas and limit the efficiency of electron cooling. We cannot confirm certain mean-field predictions on the influence of an external magnetic field on the cooling process. A study of the relaxation of anisotropic velocity distributions for a one-component plasma shows deviations from meanfield results for strongly coupled plasmas.

The Publisher is very sorry for not listing this article on the Table of Contents for Volume 20, Number 1, 2002.

Third-harmonic Brillouin backscattering (3HBBS) instability is investigated in the interaction of a picosecond extraordinary laser pulse with a homogeneous transversely magnetized underdense plasma. Nonlinear coupled equations that describe the instability are derived and solved for a weakly coupled regime to find the maximum growth rate. The nonlinearity arises through the combined effect of relativistic mass increase, static magnetic field, and ponderomotive acceleration of plasma electrons. The growth rate is found to decrease as the static magnetic field increases. It also increases by increasing both plasma density and laser intensity. It is also established that the growth rate of 3HBBS instability in a magnetized plasma is lower than that of fundamental Brillouin backscattering instability.

The results of high-power ion beam (HPIB) generation and in the magnetically insulated diode (MID) installed on a 3 × 1010-W nanosecond accelerator are given. The possibility of efficient HPIB ballistic focusing with the use of the preformed plasma in the HPIB transport region was demonstrated.

Several new diagnostics (spring pendulum and acoustic probe) were used to measure the plasma ablation pressure during the impact of the HPIB with the target.

The highest degree of HPIB focusing attained during the experiments with spherical geometries of the diode electrodes was equal to 60. The ablation average pressures measured by the spring pendulum gave several kilobars for 8–10 kA/cm2 of HPIB density. The peak pressure measured by acoustic probes attained tens of kilobars for the same HPIB current amplitudes.

Taking into account the stochastic excitation of the atoms (as quantum structures), we can suggest an absolutely new conception of a wide spectrum of processes in a femtosecond laser produced plasma. The electromagnetic fields being achieved with the modern laser technique exceed intraatomic fields by several orders. This fundamentally changes the physics of their interaction with the atomic structures. The atom effectively transforms the energy of radiation falling on it into fluxes on the nucleus. Quantum systems spin interaction with vector potential field being to play the essential role.

The future utility of inertial confinement fusion requires a new driver. Successful experiments coupling laser energy to targets, and our understanding of fuel capsule behavior strongly suggest that a Laboratory thermonuclear source is attainable and power production may be considered if a suitable driver with high efficiency, high repetition rate, and most importantly, low capital cost, can be identified. No adequate driver exists today; however, the krypton fluoride laser holds great promise (Rosocha et al. 1986). By the end of this decade, driver development can be brought to the point that a technically justifiable choice can be made for the future direction of ICF.

This was the first international meeting for unclassified research worldwide on X-ray lasers. There were 86 participants from 10 countries. It was organized most perfectly in the French Alps just before the end of the skiing season by Pierre Jaegle (Universite Paris-Sud, Orsay) who himself may be considered as one of the first, in the field of X-ray lasers. Jeagle et al. published, in 1971, a paper on the extraordinary increase of the 117 angstrom aluminium lines when a target was irradiated by laser and a comparison with cases emitted from different volumes. His result was highlighted in 1973 by Benjamin Lax and Art Guenther (1974): ‘The most definitive evidence of non-equilibrium population of excited atomic states in a laser-produced plasma was obtained by Jaegle et al. at the University of Paris in Orsay’.

A high-power Nd3+:glass laser system has been constructed and tested. This system consists of a master oscillator, a four-pass amplifier for preamplification, and five-stage amplifiers. The system has been demonstrated in excess of 80 J (2 TW) at 40-ps pulse duration. Final laser beam quality was quite good due to the compensation of the polarization distortion in the four-pass preamplifier, the minimization of the diffraction effect by the image relaying, and the elimination of high spatial frequency components by the spatial filtering. This enables us to obtain high laser output power without any severe spatial spiking effects. Gains and spatial profiles of output pulses were measured after each amplifier stage.

Scattered emission from the laser plasma created in shell target heating experiments using the Delfin-1 laser has been studied. It is shown that the ω0 spherical harmonics can be used to determine both the plasma temperature in the nc/4 region and also the plasma flow through this region.

The interaction of a plasma produced by irradiation of perforated foils with laser pulses was studied. The laser beam of the first harmonics of the iodine laser (λ = 1.315 μm) system PERUN was focused by anf/2 optics (f = 20 cm) on a hole in the foil target of high-Z material. The laser energy and the temporal shape of the pulses were monitored both before and behind the hole. Foils of two different materials (Pb, Cu) were used, and a series of hole diameters 2rH ranging from 100 μm to 500 μm were tested. The diameter of the laser focal spot 2r0 was about 150 μm. For hole diameters smaller than 300 μm, a shortening of the laser pulse was observed, demonstrating the effect of plasma shutter. The pulse shortening, which depends on the hole diameter, corresponds to the reduction in the pulse energy passing through the hole. An analysis of the experimental data is based on hydrodynamic computations, and the physics of the process is illustrated by a simple analytical model.

The acceleration of test electrons by a resonant, one—dimensional electric structure is studied in the convective regime with the Zakharov equations. Depending on the nonlinearity level the particle acceleration is due to diffusion or trapping by the plasma wave. Electron distributions are obtained and compared with 1-D particle code results. Influence of Landau damping formulation is discussed.

At the start of a new volume I want to take the opportunity to thank the associate editors and the editorial board members whose terms ended recently for their many years of service to the scientific community and to this journal especially. I personally had a lot of help from all of them, and I dare to ask for their continued support for this journal. The attentive reader may notice quite a change in the editorial team. Therefore this is also the opportunity to welcome the new board members and to wish them success for their editorial work.

We report on an experiment demonstrating the high degree of mutual phase coherence between two white-light continuum pulses independently generated by phase-locked ultrashort laser pulses. We show that these secondary pulses are locked in phase and exhibit surprisingly clear and stable Young's interference fringes when overlapped on a screen in the far field. We discuss the use of such phase-locked continuum pulses in the realization of a new kind of ultrabroad frequency comb for absolute frequency measurements throughout the visible spectrum.