A previous hydrodynamic model of the expansion of a laser-produced plasma, using classical (Spitzer) heat flux, is reconsidered with a nonlocal heat flux model. The nonlocal law is shown to be valid beyond the range of validity of the classical law, breaking down ultimately, however, in agreement with recent predictions.

Non-paraxial approximation based study of transient self-focusing of an intense short-pulse laser in plasma has been investigated by considering the effect of a transverse magnetic field. The laser with non-uniform distribution of intensity exerts a ponderomotive force on electrons and sets in an ambi-polar diffusion of the plasma. The ambient magnetic field, however, strongly inhibits the process, when the electron Larmor radius is comparable to or shorter than the laser spot size. As the plasma density is depleted, the laser beam becomes more self-focused. This study addresses a significant enhancement in the laser self-focusing rate by including the correction terms due the off-axis approximation.

The discussion of parallel electric fields in the earth's magnetosphere has undergone a notable shift of emphasis in recent years, away from wave-generated anomalous resistivity towards the more large-scale effects of magnetic confinement of current carrying plasmas. This shift has been inspired in large part by the more extensive data on auroral particle distribution functions that have been made available, data that may often seem consistent with a dissipation-free acceleration of auroral electrons over an extended altitude range.

Efforts to interpret these data have brought new vigor to the concept that a smooth and static electric field can be self-consistently generated by suitable pitch-angle anisotropies among the high-altitude particle populations, different for electrons and ions, and that such an electric field is both necessary and sufficient to maintain the plasma in a quasi-neutral steady state. This paper reviews and criticizes certain aspects of this concept, both from a general theoretical standpoint and from the standpoint of what we know about the magnetospheric environment. It is argued that this concept has flaws and that the actual physical problem is considerably more complicated, requiring a more complex electric field, possibly including double layer structures.

This paper presents the results of relativistic calculation intended specifically to investigate the dominant states for dielectronic recombination of Li-like into Be-like Al ions in short-pulse laser produced plasmas. The relativistic Dirac R-matrix calculation is performed to output resonance energy levels and rates. The target energies and orbitals are calculated with the extended average level multi-configurational Dirac-Fock method in the general-purpose relativistic atomic structure package. This type of calculation gives a set of 13 bound orbitals that is optimized over all the levels included. The resulting 13 relativistic orbitals produced 74 Jπ levels, all of which are to be used in the close-coupling expansion. To the best of our knowledge, the work reported herein describes for the first time such detailed calculation for this atomic system and the results are relevant to the short-pulse laser produced plasma modeling.

The interaction of intense laser light with molecules and clusters is a rapidly evolving research area. Its attraction lies in both the underlying fundamental physics and the prospects for applications. The interaction of intense laser light with rare-gas clusters, for instance, leads to megaelectron volt electrons, multikiloelectron volt ions, and bright X-ray emission. In laser-irradiated D2 clusters, thermonuclear fusion has been achieved.

The fluid-dynamics of the corona ejected by laser-fusion targets in the direct-drive approach (thermal radiation and atomic physics unimportant) is discussed. A two-fluid model involves inverse bremsstrahlung absorption, refraction, different ion and electron temperatures with energy exchange, different ion and electron velocities and magnetic field generation, and their effect on ion-electron friction and heat flux. Four dimensionless parameters determine coronal regimes for one-dimensional flows under uniform irradiation. One additional parameter is involved in two-dimensional problems, including the stability of one-dimensional flows, and the smoothing of non-uniform driving.

Evidence of gain in a recombining Z-pinch plasma has been obtained at 52 and 49.8 nm. The amplified XUV radiation originated from the 4f-3d and the 4d-3p transitions of Lilike oxygen, OVI. The plasmas were generated in a small diameter Z-pinch discharge with moderate currents of 40 kA. The gain coefficient was determined by variation of the pinch tube length, leading to a gain-length product of 2.5 (4f-3d) and of 2.2 (4d-3p) for a length of 9 cm.

A high-irradiance short pulsed laser was used to generate hemispherical shock waves in planar targets. A linear relationship was obtained between the laser energy for threshold spall conditions (EL) and the cubic target thickness (d): EL = 45.3d3 + 4.9, where EL is in J and d is in mm. It is found that the laser-induced ablation pressure decays with the distance to a power slightly greater than 2.

In the present analysis we study the weakly nonlinear coupled dynamics involving focused radiation beams and space-charge fields in laser-plasmas systems. We direct the analysis to regimes evolving with the co-moving coordinate of the beam frame, but do not make any assumptions on paraxial or underdense conditions. The model thus constructed allows us to investigate equilibrium and nonequilibrium regimes alike. Dependence of equilibrium profiles on control parameters is examined, and beam stability and evolution is investigated as one adds small mismatches to the ideally matched equilibrium. Details of beam evolution depend on initial conditions. However, independently of the precise form of initial conditions, mismatched beams evolve to incoherent space-time patterns.

A simple heuristic model is developed to examine the feasibility of using radiation pressure as a means to transport plasma dust out of the path of the forthcoming electron or photon beam. A slow electromagnetic surface wave coupled to a planar target or substrate exerts the required pressure in the removal process. The model is examined using data and parameters from single-shot radiography experiments. Optimal source requirements are identified for a typical radiography experiment. Source energies and powers are a minimum over an optimum band of frequencies where both conduction and plasma oscillation effects are mutually significant. Above the band of frequencies, dissipative losses in the surface supporting the surface wave increases exponentially with frequency. Below the optimal band, the energy concentration over the plume at the surface structure decreases significantly with frequency, thereby requiring higher source energies/powers for plasma removal.

2D, low-frequency, relativistic solitary waves have been found recently in 2D. Particle-in-cell simulations of ultraintense laser pulses propagating in underdense plasmas, in regimes where the laser pulse undergoes energy depletion and downshifting of its frequency. These slowly propagating, spatially localized, electromagnetic structures represent an important channel of energy conversion from the laser pulse to the plasma. Pulse energy can also be converted into fast propagating structures, associated with collimated beams of ultrarelativistic electrons. Lienard–Wiechert magnetic field structures have been observed in PIC simulations to move together with focalized ultrarelativistic electron beams in the plasma.

In this paper we compare the requirements for a light ion beam driven inertial confinement fusion (ICF) reactor with the present achievements in pulsed power technology, ion diode performance, beam transport, and target physics. The largest gap exists in beam quality and repetition rate capability of high-power ion diodes. Beam quality can very likely be improved to a level sufficient for driving a single-shot ignition facility, if the potential of two-stage acceleration is used. Present schemes for repetition rate ion diodes allow either too low power densities or create too large beam divergence. On the other hand, repetitively operating pulsed-power generators meeting the requirements for an ICF reactor driver can be built with present technology. Also, a rather mature target concept has been developed for indirect drive with light ion beams.

The first experiments to study the shell's controlled asymmetry of capsule with DT-fuel in a highly symmetrical X-ray field, which is obtained inside a spherical hohlraum, were implemented. The asymmetry results from the coating of one hemisphere with the additional layer of material. The main goal of the experiment was to define the value of the capsule asymmetry, allowing us to experimentally obtain the neutron yield, which would be very different from the yield obtained in the experiment with the spherically symmetrical shell having the same mass as the asymmetrical one. It was shown that the shell asymmetry of ∼50% leads to the ∼(2–4) times reduction of the neutron yield as compared with the symmetrical shell. 2D calculations of the asymmetric capsule compression, using the MIMOZA-ND code, were conducted. The calculations demonstrated that the compression of targets, when exploding pusher regime occurs has a complicated character. The computational neutron yield, and the delay of the neutron generation time are in good agreement with the experimental data.

We propose to build up a facility of sub-picosecond hard X-ray pulses based on Thomson scattering between femtosecond laser pulses and relativistic electrons which is a useful tool for the purpose of material investigation, plasma diagnostics, and shock wave measurement. This article reviews the principles and the development of X-ray sources based on Thomson scattering. Then New Light Source®, the Thomson scattering X-ray facility we will develop is introduced. The characteristics of a Thomson scattering X-ray source are analyzed. A computer model of the Thomson source to be developed is described in order to provide a source of the rays used in a ray tracing method, which has proved to be an essential computer tool for designing and optimizing the optical system of high brightness X-ray facilities. A code for the ray tracing source model is created based on the Monte Carlo approach. It is able to evaluate the properties and performances of the light source under development using this model. According to the simulation results, we discuss the dependence of imaging quality and source properties including spectral distribution, emittance, flux which depends on the laser and electron beam parameters, in order to check if operation performances are as expected. We also estimate the possibility of measuring the energy spectrum of a Thomson scattering source by using a crystal diffraction method. Ray tracing calculations are performed using SHADOW program package, and a new model of Thomson scattering X-ray source which can be processed in that program is established with additional code.

The use of nuclear radiation to excite lasers is examined from the perspective of nuclear flashlamps. Nuclear driven flashlamps can also be used as photon sources for photochemical and photovoltaic events. This can lead to the large scale production of chemicals and electricity.

This paper presents a comparison of Haan's mode coupling model with two-dimensional hydrocode simulations. In the light of these results, a new saturation criterion is developed that is used in a new, extended mode coupling model. The new extended model accurately follows the mode development to amplitudes 2 to 3 times larger than Haan's model.

The fractures of a soda-lime glass surface layer were investigated under irradiation by a high-power ion beam of nanosecond duration with different current densities. Two kinds of cracks (perpendicular and approximately parallel irradiated surfaces) have been identified. It is defined that cracks approximately parallel to the surface are localized at a depth of 10 ± 2 µm from the irradiated glass surface after one-time irradiation with a current density of 100 A/cm2. The formation of these cracks was detected within ~170 h after the end of irradiation when irradiated samples were under an air atmosphere. In a vacuum, the growth of these cracks was insignificant. It is shown that irradiation of heated glass or heating of glass started no later than 2–3 min after irradiation can suppress or substantially reduce surface fracture of glass. The possible mechanisms of glass fracture were discussed.

A perturbation method in which only the most secular terms are retained gives simple results for the weakly nonlinear growth of a single-mode shock-accelerated interface (Vandenboomgaerde et al., 2002). This result can be written as a series in integer powers of time. It can be considered as the Taylor expansion of an analytic function. We believe that an approximation of such a function has been identified; it described the evolution of the instability from linear to intermediate nonlinear regime. Furthermore, this function has no singularity. The relevance of this analytic formula is checked against two-dimensional simulations and experimental data.

In this paper, we report on the acceleration of protons and oxygen ions from tens of micrometer large water droplets by a high-intensity laser in the range of 1020 W/cm2. Proton energies of up to 6 MeV were obtained from a hybrid acceleration regime between classical Coulomb explosion and shocks. Besides the known thermal energy spectrum, a collective acceleration of oxygen ions of different charge states is observed. 3D PIC simulations and analytical models are employed to support the experiential findings and reveal the potential for further applications and studies.