In inertial fusion, one of scientific issues is to reduce an implosion non-uniformity of a spherical fuel target. The implosion non-uniformity is caused by several factors, including the driver beam illumination non-uniformity, the Rayleigh–Taylor instability (RTI) growth, etc. In this paper, we propose a new control method to reduce the implosion non-uniformity; the oscillating implosion acceleration δg(t) is created by pulsating and dephasing heavy-ion beams (HIBs) in heavy-ion inertial fusion (HIF). The δg(t) would reduce the RTI growth effectively. The original concept of the non-uniformity control in inertial fusion was proposed in [Laser Part. Beams (1993) 11, 757–768]. In this paper, it was found that the pulsating and dephasing HIBs illumination provide successfully the controlled δg(t) and that δg(t) induced by the pulsating HIBs reduces well the implosion non-uniformity. Consequently the pulsating HIBs improve a pellet gain remarkably in HIF.

Even though general conclusions cannot be derived for all the protection schemes in inertial confinement fusion (ICF) reactors, the feasibility of the ferritic alloy HT-9 as the main component of the first structural wall (FSW) in ICF facilities using thin-film Li17Pb83 liquid protection, flowing through porous tubes (INPORT), can be demonstrated as a solution in terms of radiation damage. Swelling and shift in the ductile-brittle transition temperature (DBTT) can be analyzed using the results of experimental fast-fission reactors, which are demonstrated to be good experimental tools in that ICF range. The good performance of HT-9 is remarkable. The generation of new solid transmutants and the depletion of initial constituents need also be considered. Further, a reduced-activation HT-9 (niobium-free) has been studied using recycling and shallow land burial (SLB) criteria. The recycling using that HT-9 is shown to be not feasible, as is SLB waste disposal. The unexpected critical role of some short-lived isotopes is remarkable, and more research on their nuclear data must be performed.

We observe experimentally periodic proton beam filamentation in laser-produced dense plasma using multilayered (CH–Al–CH) sandwich targets. The accelerated MeV proton beams from these targets exhibit periodic frozen filaments up to 5–10 µm as a result of resistive Weibel instabilities in the expanding plasma. The evolution of strong self-generated resistive magnetic fields at the targets interface is attributed to such plasma effects, which are supported, by our theory and simulations. We suggest that the resistive Weibel instability could be effectively employed to understand the evolution of magnetic fields in laser-generated plasma in the astrophysics scenario or the advanced fast igniter approach of the inertial confinement fusion.

The growth of the Rayleigh-Taylor instability in three dimensions is ex amined during the deceleration phase of an inertial confinement fusion implosion. A detailed discussion of the three-dimensional hydrocode, PLATO, is presented. A review of previous calculations is given, concentrating on theshape of the R-T instability in three dimensions. Results of the growth rate during the linear phase, the saturation amplitude, and the nonlinear evolution are presented.

The quantum behavior of the system composed of an electron in an electromagnetic field is described by the Dirac equation, whose solution is a wave function represented by a column matrix with four components. We prove, without using any approximation, that these components can be put in a form which reveals directly the values of the electron energy, laser beam intensity, or amplitude of the electric field intensity, for which the quantum electrodynamics effects are generated. Our results are in good agreement with the experimental data reported in the literature. We prove that the four components of the wave function verify the continuity equation of quantum electrodynamics. Our treatment is in good agreement with the Compton relation. We show that the interaction of electrons with laser beams could be modeled using classical approaches regardless of the laser beam intensity as long as the electrons are non-relativistic, in agreement with published experimental data.

The role played by the angle of incidence of a short pulse laser in the generation of magnetic field via Weibel instability from overdense plasmas is investigated with the help of three-dimensional particle-in-cell simulations. The simulations have been done for different cases by varying the angle of incidence. When the laser pulse is incident normally (θ = 0°), it gets self-focused at a very short distance and the axial intensity rises up to several times the fundamental laser intensity. Strong current filamentation is observed, which causes the generation of high magnetic fields across the current filament. When the laser is incident obliquely at θ = 30° and 60°, periodic density ripple-like structures are formed on the plasma surface which is due to emission of energetic electron jets caused by vacuum heating. The periodic structures carry forward and return currents, which results in the formation of periodic magnetic field structures having strong magnetic fields. At θ = 60°, the inter spacing distance coincides with the incident laser wavelength. The magnetic energy is found to be highest in case of normal incidence, which is due to strong current filamentation. The filamentation becomes weaker as the angle of incidence is increased.

As an important part of my duty and as a first step as incoming editor to this journal it is a great pleasure for me to thank Professor George H. Miley for his work that he did for over a decade as the editor-in-chief of Laser and Particle Beams. During a period of over 20 years, the field, which this journal has set out to address, has experienced enormous progress. George H. Miley steered the journal safely through uncharted waters and always found a way to keep the delicate balance between the needs of readers, authors, and the publisher as well. The journal is now regarded to be highly prestigious and it is listed among the top ranking scientific journals with peer review systems. When we compare this journal to others, we have to keep in mind that it is not made by professional journalists but rather by fellow scientists for scientists. During all these years George Miley managed to have this journal serve the needs of the scientific community and he was very successful in this difficult enterprise. Thank you George!

This paper presents the multigigawatt single-beam CO2 laser system and the configuration and the main subsystems of the 0.5 TW four-beam CO2 laser system being built at the IPPLM. Selected construction details and early test results are given.

We study dynamics, structure and organization of the new paradigm of wavewrinkle structures associated with multipulse laser-induced RayleighTaylor (RT) instability in the plane of a target surface in the circumferential zone (C-zone) of the spot. Irregular target surface, variation of the fluid layer thickness and of the fluid velocity affect the nonlinearity and dispersion. The fluid layer inhomogeneity establishes local domains arranged (organized) in the «domain network». The traveling wavewrinkles become solitary waves and latter on become transformed into stationary soliton wavewrinkle patterns. Their morphology varies in the radial direction ofaussian-like spot ranging from the compacton-like solitons to the aperiodic rectangular waves (with rounded top surface) and to the periodic ones. These wavewrinkles may be successfully juxtapositioned with the exact solution of the nonlinear differential equations formulated in the KadomtsevPetviashvili sense taking into account the fluid conditions in particular domain. The cooling wave that starts at the periphery by the end of the pulse causes sudden increase of density and surface tension: the wavewrinkle structures become unstable what causes their break-up. The onset of solidification causes formation of an elastic sheet which starts to shrink generating lateral tension on the wavewrinkles. The focusing of energy at the constrained boundary causes the formation of wrinklons as the new elementary excitation of the elastic sheets.

This issue of Laser and Particle Beams contains 27 contributed articles based on presentations given at the eighth International Workshop on the Physics of Compressible Turbulent Mixing (IWPCTM) (see http://www.llnl.gov/IWPCTM), held at the California Institute of Technology, Pasadena, California from December 9 to 14, 2001, and organized jointly by the Lawrence Livermore National Laboratory (LLNL) and the California Institute of Technology. This conference is the eighth in a biennial series of conferences on the general subject of experimental, numerical, and theoretical studies of compressible turbulent mixing, initiated by LLNL in the late 1980s. Previous conferences were held in Princeton, New Jersey (1988), Pleasanton, California (1989), Royaumont, France (1991), Cambridge, United Kingdom (1993), Stony Brook, New York (1995), Marseille, France (1997), and St. Petersburg, Russia (1999). The ninth IWPCTM is to be held at the University of Cambridge in 2004.

The process of induced bremsstrahlung is studied and it is found that anisotropy in the electron distribution can lead to the amplification of radiation. The gain rate is ,Λ where ν is the electron-ion collision frequency, ωp and ω the plasma and radiation frequency, and Λ a numerical factor which is positive only for anisotropic distributions.

Intense ion beams can be used to generate ultrahigh pressures in condensed matter. Lightion beams generated at the Karlsruhe Light Ion Facility (KALIF) typically have a focus of less than 1-cm diameter. The maximum power density at KALIF achieved so far is of the order of 1 TW/cm2. In the energy deposition zone of the targets, the 1.5-MeV protons of the KALIF beam deposit energy of the order of 100 TW/g or 5 MJ/g. A strongly coupled, hot, dense plasma is thus created by the action of a light ion beam on matter. The high pressure generated in this region has been used to accelerate thin foils to velocities up to 12.5 km/s. A successful interpretation of these experiments can serve as a check of theoretical models and of the equation of state (EOS) data. The present paper contains an investigation of the hydrodynamics of thin aluminum foil accelerated by light ion beams at KALIF using Bθ0-diode. The peak power density in these experiments was 0.15 ± 0.05 TW/cm2. The results of simulations depend mainly on two factors: power density evolution at the target and the EOS for the strongly coupled dense and hot plasma. The beam power density evolution has been carefully remeasured recently. It turned out that the available EOS data do not reproduce experimental results satisfactorily. We have formulated a simple EOS formula in a modified Mie-Grüneisen form. We assume the Grüneisen parameter to be a function of temperature and density. The parameters of this EOS have been adjusted to reproduce experiments at KALIF. In the present paper analysis of beam-target interaction experiments at KALIF is presented using our analytic EOS. We show that such experiments can give information on EOS data in the region of strongly coupled plasma.

A commercial mode locked cavity dumped Nd:YAG dye laser operating at 10 Hz repetition rate is modified to produce a high contrast (>5000:1) single laser pulse while maintaining the energy stability and high beam quality. A trigger generator biases the cavity dumping photodiode, which is triggered externally by a pulse from the microprocessor-based control unit controlling a ∼2 J/200 ps laser chain. In the laser chain, the high contrast (>5000:1) is achieved by an external pulse selector based on single Pockel's cell to select a single laser pulse of high contrast, which is a prerequisite for experimental study of the equation of state. Laser-induced shock velocity measurement in thin aluminum, gold on aluminum, and copper on aluminum foil targets using this modified laser system are also presented. The equation of state of Al, Au, and Cu obtained using an impedance matching technique are in agreement with the reported results of SESAME and simulation results.

We first pay attention to the inflight charge state distribution in a Pb ion beam propagating in a reactor-sized chamber delimited by metallic walls. We thus compare Livermore (code BIC) and Orsay (code BPIC) distributions in the presence of a residual Flibe gas pressure. Next, we replace the electron plasma due to Flibe ionization by a gliding plasma produced by the polarization of the incoming ion beam on insulating walls. Corresponding electrons, when attracted by the beam, are demonstrated to yield a very efficient current neutralization.

A nonlinear theory of ion stopping in classical ideal plasmas is formulated on the basis of formalism of higher-order dielectric functions accounting for nonlinear relationship between polarisation and electric fields generated in plasma by the projectile ion. Corrections to the linear theory corresponding to the Barkas effect are evaluated explicitly. The result differs (what concerns the numerical coefficient) from that following from the harmonic oscillator model.

The achievement of hypervelocities (40 km/s or more) is considered by the electrostatic simultaneous acceleration of dust particles positively and negatively charged. This ensures current neutralization. Beams carrying several grams of matter look feasible. The mutual impact of these macroparticles results in temperatures in the fusion range.

In this paper the classical theory of Above Threshold Ionization (ATI) in the oxygen plasma was used to show how the residual electron energy depends on the laser parameters such as pulse length, wavelength and peak intensity. The value of ATI energy is found to increase with laser wavelength and its intensity. Our study conducted for three cases of τ > 2π/νp, τ = 2π/ωp, and τ < 2π/ωp, where ωp is the plasma frequency, reveals that the ATI energy is decreased for the pulse duration τ ≠ 2π/ωp. Also it is showed how the space charge effect can reduce the residual electron energy to a minimum value, in a suitable condition. By optimizing various parameters, we can generate the cold electrons suitable for the recombination x-ray laser.

Experimental spectra of hot dense plasmas of aluminium produced by the interaction of a subpicosecond laser with solid targets at 1016 and 5 × 1017 W/cm2 are analyzed and discussed. A detailed analysis of the K-shell spectra is given through time-dependent calculations of atomic physics postprocessed to Fokker-Planck calculations of the laser-matter interaction. The non-Maxwellian character of the electron distribution function is shown. An evaluation of the electronic density and of the ion temperature 7i will be presented through Stark line broadening calculations. An X-ray spectrum from a Tantalum target also will be presented along with a preliminary interpretation.