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Laser pulse contrast exceeding 10^11 was demonstrated on a kilojoule-class petawatt laser for fast ignition experiments (LFEX) laser system [J. Phys. IV France133, 81 (2006)10.1051/jp4:2006133016] by implementing a 2 in. plasma mirror. Laser beams of up to 1.2 kJ striking the plasma mirror with a pulse duration of 1.5 ps were reflected and focused onto a target without significant distortions in the focal spot. Transmitted light from the plasma mirror reveals that it has a high reflectivity 2 ps before the main peak. The estimated laser pulse contrast at the target was 10^11 at 1 ns before the main peak. No preformed plasma was observed with an optical interferometry diagnostics, but in the experiment without a plasma mirror a preplasma was clearly observed. The energetic proton was generated from a 0.1 μm thick CH film showing excellent pulse contrast. This technique constitutes a promising method to enhance the LFEX laser system performance in fast ignition experiments.

The recent fast heating of a compressed core to 0.8-1?keV temperature as well as the previous high-density compression of 600 times liquid density have provided proof-of-principle of the fast ignition (FI) concept. These results have significantly contributed to official approval of the first phase of the FI realization experiment (FIREX) project. The goal of FIREX-I is to demonstrate fast heating of a fusion fuel up to the ignition temperature of 5-10?keV. Although the fuel of FIREX-I is too small to be actually ignited, sufficient heating will provide the scientific viability of ignition and burn by increasing the laser energy, thereby increasing the fuel size. The FIREX programme is being carried out in collaboration with the Institute of Laser Engineering, Osaka University and the National Institute for Fusion Science, including the development of cryogenic targets, holistic simulation systems and diagnostic equipment.

Effects of an implosion nonuniformity with ℓ = 1 (ℓ: Legendre polynomial mode number) on the hot spark formation were investigated in a series of direct-drive implosion experiments at the Gekko-Xll glass laser (Yamanaka et al., 1987). The implosion dynamics and the performance from the early to final stage of the implosion were observed with a variety of X-ray imaging and neutron diagnostics. A drive nonuniformity in the implosion with ℓ = 1 was observed in the shape of the accelerated target at the early stage of the implosion. At the final stage of the implosion, the resultant nonuniformity with ℓ = 1 was also observed as a geometrical shift of core plasmas from the center of the chamber. The observed neutron yield and X-ray emission properties at the final stage of the implosion were significantly degraded with an increase of the implosion nonuniformity with ℓ = 1. The experimental results were compared with one-dimensional (1-D) and two-dimensional (2-D) hydrodynamic simulations. As a result, it was found that the implosion nonuniformity with ℓ = 1 shifts the whole implosion dynamics towards its direction and prevents the confinement of the gas fuel considerably. However, the experimentally observed degradation in the hot spark formation, such as reductions in neutron yield and features in X-ray emission, can be reproduced in 2-D simulations not with an asymmetric perturbation of ℓ = 1 only but with multimode nonuniformities such as ℓ = 1 coupled with some additional middle-mode ones (e.g., ℓ = 6). Such a complex spike structure caused by the multimode nonuniformities was found to be essential for the experimentally observed rapid cooling of the hot spark.

We investigate the photoluminescence (PL) and photoluminescence excitation (PLE) spectra of 20Al(PO3)3--80LiF+Pr glass (APLF+Pr) and Pr3+-doped LiCaAlF6crystal (Pr:LiCAF) in order to determine the electronic states of Pr3+in APLF glass host and to improve APLF+Pr scintillation properties. Ultraviolet (UV) emission bands at around 250 and 340 nm were observed from both materials and these can be ascribed to $\text{4f5d}\rightarrow \text{4f$^{2}$}$ transitions in Pr3+. Emission at around 400 nm was also obtained and is principally attributed to $\text{$^{1}$S$_{0}$}\rightarrow \text{4f$^{2}$}$ transition. Difference in the emission profiles of these two materials was found to be due to the extent of the 5d band and its position relative to the 1S0state. Increasing the concentration of Pr3+up to 2 mol % was found to improve UV emission ratio due to the faster cross-relaxation of 4f states. This could improve the quantum efficiency of APLF+Pr as a neutron scintillator for scattered-neutron diagnostics in laser fusion research.

We demonstrate the potential of a hydrothermal method-grown ZnO as a high-spatial resolution imaging device for in-situsoft X-ray laser diagnostics by characterizing the exciton emission patterns. By plotting the emission pattern radii at each position, we estimated the evolution of the beam radius around the focal point. The beam profile of the Ni-like Ag ion plasma laser was estimated from the waist radii as 29 and 21 μm, the divergence angle as 7.2 and 11 mrad and the $M^{2}$ factor as 47 and 50 in the horizontal- and vertical-axis, respectively. Spatial resolution of the magnifier was estimated to be 6 μm and is expected to improve by optimizing the optics of the magnifier and using a telescope. Our results would enhance the use of ZnO as an imaging device that would play a crucial role in the development and application of soft X-ray light sources.

Ce:LuLiF4is evaluated as a fast scintillator using a storage ring free-electron laser operating in the deep-ultraviolet region. The relatively flat spectral response across its absorption bands makes this material an attractive scintillator for various excitation sources. Its decay time is acceptable for ignition timing in fast-ignition, inertial confinement nuclear fusion using laser. This report is the first systematic study on Ce:LuLiF4as a scintillator, wherein the storage ring free-electron laser is also shown as a powerful tool for material survey.

In this paper, we report on three-photon fluorescence and the possible observation of other complex optical processes in a ZnSe crystal for a kilojoule-class, 100 ps pulse, Nd:glass laser excitation. The emission properties of the ZnSe crystal and its excitation energy dependence were investigated under low and high-energy excitations. A 15 to 10 nm full width at half maximum (FWHM) spectral collapse, a 5 nm blue shift, and a shortened lifetime of fluorescence under high-energy excitation could indicate an amplified spontaneous emission. These findings present the feasibility of investigating the dynamics and spectral properties of three-photon fluorescence and other complex nonlinear optical processes in ZnSe at an extremely high excitation energy.

The Fourth International Conference on Inertial Fusion Sciences and Applications (IFSA 2005) was held September 4-9, 2005 at the Bellevue Conference Center in Biarritz, France. The host organizations for this conference were the University of Bordeaux 1, the Centre National de la Recherche Scientifique (CNRS) and the Commissariat a l'Energie Atomique (CEA). The conference objective was to review of the state of the art of research in inertial fusion sciences and applications since the last conference held in Monterey California, USA, in 2003. Altogether 509 abstracts were submitted, 418 accepted, and more than 440 persons from 23 countries attended the conference. These Proceedings contain 249 of the papers presented at IFSA 2005. This collection of papers represents the manuscripts submitted to and passing the peer review process. 
The IFSA 2005 conference is the first of a new series of three conferences to be organized in France, Japan and the USA and governed under Annex I of the Memorandum of Agreement, signed in June 2004, among the Lawrence Livermore Laboratory operated by the University of California (UC), Osaka University, and Institut Lasers et Plasmas (ILP), operated by CNRS Delegation Aquitaine. 
The IFSA 2005 continued the strong tradition of the three previous conferences in Bordeaux, Kyoto and Monterey. It was the largest IFSA yet with a substantial participation from countries such as China and Russia. With a goal of achieving inertial fusion ignition and burn propagation in the laboratory, there continues to be significant progress in the international inertial fusion community. At IFSA 2005, researchers presented the exciting advances in traditional hot spot ignition approach, including results from the early experiments from the NIF laser. A particularly emphasis of the meeting was the rapid and exciting progress in the fast ignition scheme. Integrated and basic physics experiments on GekkoXII, Vulcan, and other laser-matter interaction facilities have shown promising results. A lot of new results of experiments and numerical simulations in ultra-intense laser interactions have also been presented. 
The Megajoule Laser (LMJ), as one of two facilities being built to achieve target ignition, was a key attraction of IFSA 2005. About 200 participants toured the LMJ construction site and the LIL laser prototype during the conference. Before the tour, a special Facility Focus session examined progress on inertial fusion facilities around the world, including the soon-to-be-completed OMEGA-EP upgrade at Rochester, USA, and FIREX I, at Osaka, Japan. Recent progresses in hohlraum physics continue to give confidence in the ultimate achievement of ignition on the NIF Laser and the Megajoule Laser. The USA are pursuing a very focused program on ICF under the National Ignition Campaign (NIC). In China, a national project has been launched, the goal of which is fusion ignition and plasma burning in about 2020. Progress in direct drive has been notable over the past few years with the cryogenic implosions at LLE, polar direct-drive that may enable to switch rapidly from an indirect- to a direct-drive laser configuration, adiabat shaping of laser pulses, and even "Saturn targets", a short circuit topic from ICF to laboratory astrophysics. About this last topic, radiative shocks and plasma jets were among the most studied subjects. There were also sessions on the technologies of al1 types of drivers, including KrF and DPSSL lasers, particle beams, and Z-pinches. Advances in Z-pinch included double-hohlraum irradiation symmetry and the construction of a PW laser beam for the Z-facility. Advance in plasma diagnostics were dominated by proton imaging from ultra-intense interactions and precise imaging spectroscopy of core implosions. Of special interest, advanced target physics and reactor design studies have started to be more present during this IFSA edition. 
These Proceedings start with special chapters on the keynote speeches and the Teller lectures. The keynotes give an overview of progress in inertial fusion in North America, Europe and Asia. The Teller lectures show the contributions of this year's two winners: Joe Kilkenny of General Atomics and Max Tabak of LLNL. The remainder of the Proceedings is divided into three parts. Part A covers the physics of inertial fusion; Part B covers facilities, lasers, particle beams, Z-pinches, target fabrication and reactor design; Part C covers fundamental high-energy density science and other applications of inertial fusion VI technology such as plasma diagnostics, atomic physics and X-ray sources, laboratory astrophysics and laser particle acceleration. The readers should be aware that for some of the papers, only a short version is presented in this book: the extended version will be published in a topical issue of the European Physical Journal. 
The IFSA International Organizing Committee and Scientific Advisory Board appreciate the efforts of inertial fusion researchers worldwide in making IFSA 2005 an extremely successful conference. 
Jean-Claude Gauthier, technical committee co-chair 
Bruce Hammel, technical committee co-chair 
Hiroshi Azechi, technical committee co-chair 
Christine Labaune, proceedings co-editor

The Fourth International Conference on Inertial Fusion Sciences and Applications (IFSA 2005) was held September 4-9, 2005 at the Bellevue Conference Center in Biarritz, France. The host organizations for this conference were the University of Bordeaux 1, the Centre National de la Recherche Scientifique (CNRS) and the Commissariat a l'Energie Atomique (CEA). The conference objective was to review of the state of the art of research in inertial fusion sciences and applications since the last conference held in Monterey California, USA, in 2003. Altogether 509 abstracts were submitted, 418 accepted, and more than 440 persons from 23 countries attended the conference. These Proceedings contain 249 of the papers presented at IFSA 2005. This collection of papers represents the manuscripts submitted to and passing the peer review process. ?The IFSA 2005 conference is the first of a new series of three conferences to be organized in France, Japan and the USA and governed under Annex I of the Memorandum of Agreement, signed in June 2004, among the Lawrence Livermore Laboratory operated by the University of California (UC), Osaka University, and Institut Lasers et Plasmas (ILP), operated by CNRS Delegation Aquitaine. ?The IFSA 2005 continued the strong tradition of the three previous conferences in Bordeaux, Kyoto and Monterey. It was the largest IFSA yet with a substantial participation from countries such as China and Russia. With a goal of achieving inertial fusion ignition and burn propagation in the laboratory, there continues to be significant progress in the international inertial fusion community. At IFSA 2005, researchers presented the exciting advances in traditional hot spot ignition approach, including results from the early experiments from the NIF laser. A particularly emphasis of the meeting was the rapid and exciting progress in the fast ignition scheme. Integrated and basic physics experiments on GekkoXII, Vulcan, and other laser-matter interaction facilities have shown promising results. A lot of new results of experiments and numerical simulations in ultra-intense laser interactions have also been presented. ?The Megajoule Laser (LMJ), as one of two facilities being built to achieve target ignition, was a key attraction of IFSA 2005. About 200 participants toured the LMJ construction site and the LIL laser prototype during the conference. Before the tour, a special Facility Focus session examined progress on inertial fusion facilities around the world, including the soon-to-be-completed OMEGA-EP upgrade at Rochester, USA, and FIREX I, at Osaka, Japan. Recent progresses in hohlraum physics continue to give confidence in the ultimate achievement of ignition on the NIF Laser and the Megajoule Laser. The USA are pursuing a very focused program on ICF under the National Ignition Campaign (NIC). In China, a national project has been launched, the goal of which is fusion ignition and plasma burning in about 2020. Progress in direct drive has been notable over the past few years with the cryogenic implosions at LLE, polar direct-drive that may enable to switch rapidly from an indirect- to a direct-drive laser configuration, adiabat shaping of laser pulses, and even "Saturn targets", a short circuit topic from ICF to laboratory astrophysics. About this last topic, radiative shocks and plasma jets were among the most studied subjects. There were also sessions on the technologies of al1 types of drivers, including KrF and DPSSL lasers, particle beams, and Z-pinches. Advances in Z-pinch included double-hohlraum irradiation symmetry and the construction of a PW laser beam for the Z-facility. Advance in plasma diagnostics were dominated by proton imaging from ultra-intense interactions and precise imaging spectroscopy of core implosions. Of special interest, advanced target physics and reactor design studies have started to be more present during this IFSA edition. ?These Proceedings start with special chapters on the keynote speeches and the Teller lectures. The keynotes give an overview of progress in inertial fusion in North America, Europe and Asia. The Teller lectures show the contributions of this year's two winners: Joe Kilkenny of General Atomics and Max Tabak of LLNL. The remainder of the Proceedings is divided into three parts. Part A covers the physics of inertial fusion; Part B covers facilities, lasers, particle beams, Z-pinches, target fabrication and reactor design; Part C covers fundamental high-energy density science and other applications of inertial fusion VI technology such as plasma diagnostics, atomic physics and X-ray sources, laboratory astrophysics and laser particle acceleration. The readers should be aware that for some of the papers, only a short version is presented in this book: the extended version will be published in a topical issue of the European Physical Journal. ?The IFSA International Organizing Committee and Scientific Advisory Board appreciate the efforts of inertial fusion researchers worldwide in making IFSA 2005 an extremely successful conference. ?Jean-Claude Gauthier, technical committee co-chair ?Bruce Hammel, technical committee co-chair ?Hiroshi Azechi, technical committee co-chair ?Christine Labaune, proceedings co-editor

Hydrothermal-grown bulk ZnO single crystals are investigated before and after gamma-ray irradiation. The irradiation does not alter the optical transparency in the visible region. The gamma rays only induce modified near-band-edge UV emission with blue-shifted peaks and shortened response times. From the initial values before irradiation, the peaks shift by 5 to 6 nm, and the response times shorten by 140 to 440 ps. We attribute these observations to the radiation-induced defects on the bulk crystals. Our results nevertheless lead to the realization of short-wavelength ZnO scintillators that can be utilized in high-energy-radiation environments.

We demonstrate high conversion efficiency for extreme ultraviolet (EUV) emission at 6.5-6.7 nm from multiple laser beam-produced one-dimensional spherical plasmas. Multiply charged-state ions produce strong resonance emission lines, which combine to yield intense unresolved transition arrays (UTAs) in Gd, Tb, and Mo. At an optimum laser intensity of 1 × 1012W/cm2, which is estimated to yield an electron temperature of around 100 eV, the maximum in-band EUV conversion efficiency (CE) was observed to be 0.8%, which is one of the highest values ever reported due to the reduction of plasma expansion loss.

4,4$”'$-Bis[(2-butyloctyl)oxy]-1,1$'$:4$'$,1$”$:4$”$,1$”'$-quaterphenyl (BBQ) dye dissolved in xylene and enriched with oxygen is shown to exhibit the characteristics of an ideal neutron scintillator for time-of-flight (TOF) measurement in a laser fusion experiment. Initial results from excitation with 290-nm pulses show that it has a 0.76-ns fast decay component and a negligible slow decay component or afterglow. By using this scintillator for TOF measurement, we have successfully discriminated between nuclear fusion-generated neutrons and X-rays. This would dramatically improve neutron diagnostics in fast ignition experiments where neutrons have to be detected in the presence of an intense X-ray burst.

The deuterium-tritium (D-T) thermonuclear reaction region of a laser-driven large-high-aspect-ratio target, which contains D-T mixture gas, has been diagnosed with an ?-particle imaging technique using a pinhole camera. The residual pusher region at the maximum compression has also been observed as an image of scattered ?-particles. Comparison between the ?-particle image and a two-dimensional hydrodynamic simulation shows that laser energy balance significantly influences the implosion uniformity.

A new direct method to measure fuel-pusher mixing rate in deutrium fuel is presented. The method involves two secondary nuclear fusion reactions, D(t, n)4He and D(3He, p)4He, where triton and 3He nucleus are the products of primary fusion reactions. The required conditions for which the method may be applied are also briefly discussed.

Filamentary structure in ablated corona plastma on laser irradiated pellet was observed in optical shadowgrams by a visible probe light. Several mechanisms are discussed and a collisional hot electron filamentation theory is proposed to explain it. Such filamentation may be a serious obstacle for spherically symmetric compression of laser fusion pellets.

This paper describes measurements of the ablation pressure for 10.6 µm and 1.05 µm laser irradiation using thin-foil acceleration observed by X-ray backlighting and X-ray streak shadow graphs of the implosion of a spherical target. At an absorbed laser intensity of 1014W/cm2, the ablation pressure was more than 10 Mbar for laser wavelengths of 10.6 µm and 1.05 µm. The results are compared with theories based on the self-regulated flow model and the flux-limited thermal conduction model.

A Wolter type-I X-ray mirror designed for laser plasma diagnostics has been fabricated by the replication method. A master mandrel has been ground by a diamond grinder and polished by a computer-controlled machine. The replicated mirror coated with gold can be used for X-rays longer than 2.5 Å. X-ray imaging tests were performed with a laboratory X-ray source.

A new target is proposed which increases both the laser absorption rate and the hydrodynamic efficiency. This target consists of a light inner shell and a massive outer shell with pinholes for entry of the laser light. The acceleration mechanism is similar to that of a cannonball. A model for this acceleration is presented and compared with hydrodynamic simulations.