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We investigate the proton generation from circularly polarized laser interaction with sandwich target consisting of C-H-C layers, where C denotes the carbon layer and H hydrogen layer. Our two dimensional particle-in-cell simulation shows that quasi-monoenergetic proton beam can be obtained. We also study several parameters effect (such as proton layer height, density of carbon layer, charge state...
High energy density states with photon pressures of more than Tera bar and thermal pressure of more than Mega bar, is now available with high power lasers. Here, the creation of high energy density novel state, material and devices is presented.
Summary form only given: We report on the encouraging progress from research on fusion fast ignition (FI) initiated by laser-driven ion beams. Compared to electrons, FI based on a beam of quasi-monoenergetic ions (including protons and especially heavier ions such as C) has the advantage of a more localized energy deposition, which minimizes the required total beam energy. High-current, laser-driven...
A thin-foil tailored hole target is proposed for an efficient production of a collimated proton beam in a laser target interaction. The tailored target has holes at the target surface. When an intense short pulse laser illuminates the thin foil hole target, transverse edge fields of an accelerated electron cloud and a proton source cloud are shielded by a protuberant part of the hole so that the proton...
This paper reviews recent experimental activity in the area of optimization, control, and application of laser-accelerated proton beams, carried out at the Rutherford Appleton Laboratory and the Laboratoire pour lpsilaUtilisation des Lasers Intenses 100 TW facility in France. In particular, experiments have investigated the role of the scale length at the rear of the plasma in reducing target-normal-sheath-acceleration...
Summary form only given. One of the key requirements for inertial confinement fusion (ICF) is a highly uniform implosion of the spherical pellet. This presentation examines simulations in great detail; e.g., allowing for the effects of defocusing and/or displacing the harmonic crystal from the exact Fourier plane. It also examines the possible advantages of an alternative partially coherent light...
Summary form only given. High-contrast pulse shaping with divergent light requires a switching element that has large angular acceptance. We used a Pockels cell with a thin crystal and plasma electrodes to demonstrate less than 0.5-ns risetime and >3000:1 contrast for 248-nm light with 6 rad divergence. Symmetric compression of laser fusion pellets requires laser light that uniformly illuminates...
Summary form only given. Nike is a multikilojoule KrF laser system located at the Naval Research Laboratory. Nike produces high-intensity uniform illumination on flat targets for experiments relating to direct-drive inertial confinement fusion (ICF). In particular we intend to study the Rayleigh-Taylor hydrodynamic instability associated with target acceleration and to develop methods to reduce the...
Summary form only given. Inertial confinement fusion (ICF) utilizing direct or indirect laser drive requires the target illumination to be uniform over a wide range of spatial frequencies. A number of approaches have been suggested to achieve the desired level of illumination uniformity. In this paper it is shown that implementing smoothing by spectral dispersion (SSD) with random-phase modulation...
Summary form only given. In this paper, we describe the Nd:glass laser amplifier mechanical design and report the results of both modeling and experiments in support of NIP and LMJ amplifier development. Gain measurements performed on a 2/spl times/2 multisegment amplifier using 4.3-cm-bore flashlamps have demonstrated 3% storage efficiencies. Ray-trace calculations agree well with the measured gain...
Summary form only given. Experiments were performed on the 100 J Optical Science Laser (OSL) at LLNL to characterize the saturation fluence and small-signal gain of a solid-state Nd:glass laser amplifier utilizing LG-750 and the proposed amplifier glass for the National Ignition Facility (NIF), LG-770.
Summary form only given. OMEGA is a 60-TW 60-beam, frequency tripled Nd:glass laser system designed to perform precision direct-drive inertial confinement-fusion (ICF) experiments. Construction and activation of the facility was completed in 1995. We report on the system configuration and its performance; then we describe the first stage of enhancements expected to improve the on-target irradiation...
Summary form only given. In this paper we describe the current design and performance of a long-pulse regenerative laser amplifier for fusion reactor ignition that uses two, diode-array, end-pumped Nd-doped glass laser amplifiers to achieve the desired performance. The regenerative amplifier is a folded linear arrangement. The 4.5-m-long cavity has a 2-m lens and mode-limiting aperture positioned...
Summary form only given. A project to develop a 1000 TW (petawatt) class laser began in 1992 in order to provide the capability to examine the fast ignitor concept for inertial confinement fusion (ICF). The laser was designed to produce 1 kilojoule pulses with a duration less than 500 fsec and be focusable to a high irradiance. Near-diffraction-limited beams require large-scale pulse compression and...
Summary form only given. Many laser plasma interaction experiments with ultrashort laser pulses either require or can significantly benefit from the use of a laser pulse with a temporal profile, which has been optimized for the experiment. We will first demonstrate experimentally that self-phase modulation is a serious issue for amplification of shaped pulses in chirped pulse amplification (CPA) systems...
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