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PDF全文 (下载：0) Matter and Radiation at Extremes, 2018年第3卷第4期 pp.1
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We present new diagnostics for use in optical laser pump - X-ray Free Electron Laser (XFEL) probe experiments to monitor dimensions, intensity profile and focusability of the XFEL beam and to control initial quality and homogeneity of targets to be driven by optical laser pulse. By developing X-ray imaging, based on the use of an LiF crystal detector, we were able to measure the distribution of energy inside a hard X-ray beam with unprecedented high spatial resolution (~1 mm) and across a field of view larger than some millimetres. This diagnostic can be used in situ, provides a very high dynamic range, has an extremely limited cost, and is relatively easy to be implemented in pumpprobe experiments. The proposed methods were successfully applied in pump-probe experiments at the SPring-8 Angstrom Compact free electron LAser (SACLA) XFEL facility and its potential was demonstrated for current and future High Energy Density Science experiments.
PDF全文 (下载：0) Matter and Radiation at Extremes, 2018年第3卷第4期 pp.197
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The interaction between a converging cylindrical shock and double density interfaces in the presence of a saddle magnetic field is numerically investigated within the framework of ideal magnetohydrodynamics. Three fluids of differing densities are initially separated by the two perturbed cylindrical interfaces. The initial incident converging shock is generated from a Riemann problem upstream of the first interface. The effect of the magnetic field on the instabilities is studied through varying the field strength. It shows that the Richtmyer-Meshkov and Rayleigh-Taylor instabilities are mitigated by the field, however, the extent of the suppression varies on the interface which leads to nonaxisymmetric growth of the perturbations. The degree of asymmetry of the interfacial growth rate is increased when the seed field strength is increased.
PDF全文 (下载：0) Matter and Radiation at Extremes, 2018年第3卷第4期 pp.207
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Based on the LINAC of BEPCII, a high-polarized, high bightness, energy-tunable, monoenergetic laser compton backscattering (LCS) gamma-ray source is under construction at IHEP. The gamma-ray energy range is from 1 MeV to 111 MeV. It is a powerful and hopeful research platform to reveal the underlying physics of the nuclear, the basic particles and the vacuum or to check the exist basic physical models, quantum electrodynamic (QED) theories. In the platform, a 1.064 mm Nd:YAG laser system and a 10.6 mm CO2 laser system are employed. All the trigger signals to the laser system and the electron control system are from the only reference clock at the very beginning of the LINAC to make sure the temporal synchronization. Two optical transition radiation (OTR) targets and two charged-couple devices (CCD) are used to monitor and to align the electron beam and the laser beam. With the LCS gamma-ray source, it is proposed to experimentally check the gamma-ray calibrations, the photon-nuclear physics, nuclear astrophysics and some basic QED phenomena.
PDF全文 (下载：0) Matter and Radiation at Extremes, 2018年第3卷第4期 pp.219
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The results of measurements of the strength characteristics - Hugoniot elastic limit and spall strength of aluminum and aluminum alloys in different structural states under shock wave loading are presented. Single-crystals and polycrystalline technical grade aluminum А1013 and aluminum alloys А2024, АА6063Т6, А1421, A7, А7075, А3003, A5083, АА1070 in the initial coarse-grained state and ultrafine-grained or nanocrystalline structural state were investigated. The refinement of the grain structure was carried out by different methods of severe plastic deformation such as Equal Chanel Angular Pressing, Dynamic Channel Angular Pressing, High-Pressure Torsion and Accumulative Roll- Bonding. The strength characteristics of shock-loaded samples in different structural states were obtained from the analysis of the evolution of the free surface velocity histories recorded by means of laser Doppler velocimeter VISAR. The strain rates before spall fracture of the samples were in the range of 104-105 s-1, the maximum pressure of shock compression did not exceed 7 GPa. The results of these studies clearly demonstrate the influence of structural factors on the resistance to high-rate deformation and dynamic fracture, and it is much less than under the static and quasi-static loading.
PDF全文 (下载：0) Matter and Radiation at Extremes, 2018年第3卷第4期 pp.145
This paper is a review of recent developments in solid-state linear transformer driver (SSLTD) for applications to pulsed power generation. It summarizes the technological advances reported by previous publications and interprets the experimental progresses. The application of solidstate LTDs has been proved to be an attractive approach to make compact and repetitive pulsed power generators that have been sought by a variety of industrial applications and scientific researches. Their advantages and disadvantages compared with their alternatives are reported and analyzed in this paper. Future technical trends of solid-state LTDs are also discussed.
PDF全文 (下载：0) Matter and Radiation at Extremes, 2018年第3卷第4期 pp.159
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The review of recent theoretical and experimental research on the complex surface chemistry processes that evolve from low-Z material conditioning on plasma-facing materials under extreme fusion plasma conditions is presented. A combination of multi-scale computational physics and chemistry modeling with real-time diagnosis of the plasma-material interface in tokamak fusion plasma edge is complemented by ex-vessel in-situ single-effect experimental facilities to unravel the evolving characteristics of low-Z components under irradiation. Effects of the lithium and boron coatings at carbon surfaces to the retention of deuterium and chemical sputtering of the plasma-facing surfaces are discussed in detail. The critical role of oxygen in the surface chemistry during hydrogen-fuel irradiation is found to drive the kinetics and dynamics of these surfaces as they interact with fusion edge plasma that ultimately could have profound effects on fusion plasma confinement behavior. Computational studies also extend in spatio-temporal scales not accessible by empirical means and therefore open the opportunity for a strategic approach at irradiation surface science studies that combined these powerful computational tools with in-vessel and ex-vessel in-situ diagnostics.
PDF全文 (下载：0) Matter and Radiation at Extremes, 2018年第3卷第4期 pp.165
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Betatron radiation from laser wakefield accelerated electrons and X-rays scattered off a counter-propagating relativistic electron bunch are collimated and hold the potential to extend the energy range to hard X-ray or gamma ray band. The peak brightness of these incoherent radiations could reach the level of the brightest synchrotron light sources in the world due to their femtosecond pulse duration and source size down to a few micrometers. In this article, the principle and properties of these radiation sources are briefly reviewed and compared. Then we present our recent progress in betatron radiation enhancement in the perspective of both photon energy and photon number. The enhancement is triggered by using a clustering gas target, arousing a second injection of a fiercely oscillating electron bunch with large charge or stimulating a resonantly enhanced oscillation of the ionization injected electrons. By adopting these methods, bright photon source with energy over 100 keV is generated which would greatly impact applications such as nuclear physics, diagnostic radiology, laboratory astrophysics and high-energy density science.
PDF全文 (下载：0) Matter and Radiation at Extremes, 2018年第3卷第4期 pp.188
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