Since 2003, the journal of Laser and Particle Beams no longer publishes conference proceedings. Even of those conferences where the topics are very closely related to the research fields discussed in this journal. Authors are instead encouraged to submit a regular paper dealing with the topic presented during a conference. The advantage for authors is that there is no page limit as long as the paper passes the peer review process. The discussion of the presented research during the conference helps reviewers to evaluate the quality of the paper and this usually leads to a speedy publication process. Every year in June, the ISI Web of Knowledge releases the Journal Citation Reports. The publication policy adopted by the Laser and Particle Beams editorial board was obviously quite successful since we experienced a substantial increase in the impact factor and in the immediacy index. Thus the Journal Citation Report lists Laser and Particle Beams now as a leading journal in the field of applied physics. This is an opportunity to thank authors for their high quality contributions to this journal. The publisher and the editorial board will try to continue to improve the service to readers and authors during the upcoming years.

The chlorine Heα radiation of polyvinyl chloride (PVC) was investigated with respect to X-ray scattering experiments on dense plasmas. The X-ray source was a laser-produced plasma that was observed with a highly reflective highly oriented pyrolytic graphite (HOPG) crystal spectrometer as it is used in current x-ray scattering experiments on dense plasmas. The underlying dielectronic satellites of Heα cannot be resolved, therefore the plasma was observed at the same time with a focusing spectrometer with spatial resolution. To reconstruct the spectrum a simple model to calculate the spectral line emission based on dielectronic recombination and inner shell excitation of helium- and lithium-like ions was used. The analysis shows that chlorine dielectronic satellite emission is intense compared to Heα in laser-produced chlorine plasmas with a temperature of 300 eV in this wavelength range of Δλ = 0.07 Å (ΔE = 43 eV). The method proposed in this paper allows deducing experimentally the role of the underlying dielectronic satellites in the scatter spectrum measured with a HOPG crystal spectrometer. It is shown that the dielectronic satellites can be neglected when the scattering is measured with low spectral resolution in the non-collective regime. They are of major importance in the collective scatter regime where a high spectral resolution is necessary.

Theoretical studies have been performed on the interaction of short laser pulse with metals. The results of the theoretical model indicate that heat conduction would not be uniform from focal spot or crater at the surface of target metal, when an ultra short laser will interact with the metal. The electromagnetic radiations of laser induce electric field inside the target that is responsible for the induction of current density, which causes electronic heat conduction in the direction of current density. Such an effect is dominant for laser pulse having duration less than of the order of sub-picoseconds. This mode will open a new significant field of study to discuss laser metal interaction for ultra short laser pulses.

An electron-beam accelerator, which consists of a primary storage capacitor system, an air core spiral strip transformer, water Blumlein line of water dielectric, and a field-emission diode, is described. The experimental results show that the diode voltage is more than 400 kV, electron beam current is about 40 kA, and the pulse duration is more than 80 ns. This accelerator is very compact and works stably and reliably.

In order to realize an effective implosion, the beam illumination non-uniformity and implosion non-uniformity must be suppressed to less than a few percent. In this paper, a direct-indirect mixture implosion mode is proposed and discussed in heavy ion beam (HIB) inertial confinement fusion (HIF) in order to release sufficient fusion energy in a robust manner. On the other hand, the HIB illumination non-uniformity depends strongly on a target displacement (dz) in a reactor. In a direct-driven implosion mode dz of ∼20 μm was tolerance and in an indirect-implosion mode dz of ∼100 μm was allowable. In the direct-indirect mixture mode target, a low-density foam layer is inserted, and radiation is confined in the foam layer. In the foam layer the radiation transport is expected in the lateral direction for the HIB illumination non-uniformity smoothing. Two-dimensional implosion simulations are performed and show that the HIB illumination non-uniformity is well smoothed. The simulation results present that a large pellet displacement of ∼300 μm is tolerable in order to obtain sufficient fusion energy in HIF.

Dense plasmas are produced using exploding wire discharges in water. Evolutions of radius, electrical conductivity, temperature of plasma and a shock wave in water accompanied with the explosion, are measured. Conductivities of aluminum, copper, and tungsten are compared with theoretical ones. To evaluate the equation of state, trajectories of the shock wave and the plasma boundary are compared with numerical calculations. Results show that the hydrodynamic behaviors are sensitive to the models of equation of state. Controllability of warm dense state in density-temperature diagram is discussed from the voltage-current characteristics of the wire discharges.

The k-L turbulence model, where k is the turbulent kinetic energy and L represents the turbulent eddy scale length, is a two-equation turbulence model that has been proposed to simulate turbulence induced by Rayleigh-Taylor (RT) and Richtmyer Meshkov (RM) instabilities, which play an important role in the implosions of inertial confinement fusion (ICF) capsule targets. There are three free parameters in the k-L model, and in this paper, I calibrate them independently by comparing with RT and RM data from the linear electric motor (LEM) experiments together with classical Kelvin-Helmoholtz (KH) data. To perform this calibration, I numerically solved the equations of one-dimensional (1D) Lagrangian hydrodynamics, in a manner similar to that of contemporary ICF codes, together with the k-L turbulence model. With the three free parameters determined, I show that the k-L model is successful in describing both shear-driven and buoyancy-driven instabilities, capturing the experimentally observed separation between bubbles and spikes at high Atwood number for the RT case, as well as the temporal mix width recorded in RM shock tube experiments.

This work describes an inductive energy storage scheme intended for power multiplication at mega-Ampere currents. The key power multiplication element of the scheme is an opening switch generating the voltage of inductive origin. The switch represents an additional volume with magnetically accelerated solid-state or plasma conductor between the generator and the load. Motion of the conductor increases the inductance of the volume. A sufficiently fast increase of this inductance at the end of magnetic energy storage time ensures power multiplication. A critical requirement for the accelerated conductor is the possibility of temporal profiling of the inductance increase. A proof-of-principle experiment at GIT12 shows that such profiling is possible. We suggest a simple analysis of the scheme efficiency and illustrate this analysis for a multi-mega-Ampere class generator. The scheme is alternative to existing inductive energy storage technologies for pulsed-power conditioning at high currents.

In this paper, the effect of a relativistically intense Gaussian laser pulse, on the propagation of electron plasma wave is studied. The nonlinear effects considered here are the relativistic decrease of the plasma frequency and the ponderomotive expelling of the electrons. Modified coupled equations for laser and electron plasma wave are derived from fluid equations. These coupled equations are solved analytically and numerically to study the laser intensity in the plasma and the variation of amplitude of the excited electron plasma wave. It is seen that the effect of including the ponderomotive nonlinearity is significant on the excitation of plasma wave. This should affect the number of energetic electrons and their energy range on account of wave particle interaction.

Laser-Compton scattering (LCS) experiments were carried out at the Idaho Accelerator Center (ICA) using the 5 ns (FWHM) and 22 MeV electron beam. The electron beam was brought to an approximate head-on collision with a 7 ns (FWHM), 10 Hz, 29 MW peak power Nd:YAG laser. We observed clear and narrow X-ray peaks resulting from the interaction of relativistic electrons with the 532 nm Nd:YAG laser second harmonic line on top of a very low bremsstrahlung background. We have developed a method of using LCS as a non-intercepting electron beam monitor. Unlike the method used by Leemans et al. (1996), our method focused on the variation of the shape of the LCS spectrum rather than the LCS intensity as a function of the observation angle in order to extract the electron beam parameters at the interaction region. The electron beam parameters were determined by making simultaneous fits to spectra taken across the LCS X-ray cone. We also used the variation of LCS X-ray peak energy and spectral width as a function of the detector angles to determine the electron beam angular spread, and direction and compared the results to the previous method. Experimental data show that in addition to being viewed as potential bright, tunable and monochromatic X-ray source, LCS can provide important information on electron beam pulse length, direction, energy, angular, and energy spread. Since the quality of LCS X-ray peaks, such as degree of monochromaticity, peak energy and flux, depends strongly on the electron beam parameters, LCS can therefore be viewed as an important non-destructive means for electron beam diagnostics.

We have focused our attention on the stopping mechanisms involved in the recently proposed ion beam-target US program. This mechanism emphasizes out production of warm dense matter through pulsed ion beams, linearly accelerated, and interacting with thin foils in Bragg peak conditions. We reviewed the relevant energy loss mechanisms involved at moderate and low velocity ion projectile. Small velocities close to zero are given some attention.

Numerical simulations of the Rayleigh-Taylor instability in the interface of two semi-infinite media have been performed based on the finite element method. Two different interfaces have been considered: elastic solid/elastic solid and elastic solid/viscous fluid. The results have been compared with previously published analytical models. In particular, the asymptotic growth rate has been compared with the model by Terrones (2005) while the initial transient phase is compared with the model by Piriz et al. (2005). Finally, some examples show the importance of such an initial transient phase if more realistic material laws (for example, elastoplastic behavior) are taken into account.

The existing “quotidian equation state” model, based on Thomas-Fermi theory, is modified so as to improve the low density region of phase diagram of metals. A scheme for estimating the critical parameters of liquid-vapor phase transition is proposed. The new model reproduces experimental critical isotherms to a good degree of accuracy. Furthermore, the proposed model is validated with thermodynamic data in the liquid-vapor co-existence region, including results on isobaric expansion as well as released isentropes.

The problem of nonlinear self-focusing of elliptic Gaussian laser beam in collisionless magnetized plasma is studied using variation approach. The dynamics of the combined effects of nonlinearity and spatial diffraction is presented. With a and b as the beam width parameters of the beam along x and y directions, respectively, the phenomenon of cross-focusing is observed where focusing of a results in defocusing of b and vice versa. Although no stationary self-trapping is observed, oscillatory self-trapping occurs far below the threshold. The regularized phase is always negative.

Stochastic pulsation of laser-plasma interaction in the range of a few to dozens of picoseconds, due to standing wave produced density ripples, needs more attention than in the past, in view of the recent developments. This is important if nanosecond laser pulses produce a pre-compression that is a thousand times the solid state density of DT for fast ignition as well as for treatment of ps laser interaction. The following is an updated summary of these properties where the laser beam smoothing is essential. The use of smoothing is not only an empirical game with experiments for improving the interaction, but it is necessary to be aware of the mechanisms involved for understanding how the pulsation is overcome, and conclusions can be derived systematically for further improvements and control of the phenomena.

(This article appeared in Volume 24, Number 2, Pages 275–282, 2006)

(This article appeared in Volume 24, Number 2, Pages 275–282, 2006)

Below is the correct Reference citation for Breil et al. (2005)

Breil, J., Hallo, L., Maire, P.H. & Olazabal-Loumé, M. (2005). Hydrodynamic instabilities in axisymmetric geometry self-similiar models and numerical simulations. Laser Part. Beams.23, 155–160.