A uniquely shaped impact structure, the Hailin impact crater, has been discovered in northeast China. The crater was formed on a granodiorite hillside and is an oval depression with asymmetric rim height and a maximum diameter of 1360 m. The bottom of the crater is filled by Quaternary sediments with large amounts of rock fragments underneath. The discovery of quartz planar deformation features in rock clasts on the crater floor provides diagnostic evidence for the impact origin of the structure. The shape of the crater is largely due to the impact having occurred on a ridge terrain. The impact event probably occurred in the late Cenozoic Era. The Hailin impact crater is the fourth confirmed Chinese impact crater.

Black-phosphorus-structured nitrogen (BP–N) is an attractive high-energy-density material. However, high-pressure-synthesized BP-N will decompose at low pressure and cannot be quenched to ambient conditions. Finding a method to stabilize it at 0 GPa is of great significance for its practical applications. However, unlike cubic gauche, layered polymeric, and hexagonal layered polymeric nitrogen (cg-N, LP-N, and HLP-N), it is always a metastable phase at high pressures up to 260 GPa, and decomposes into chains at 23 GPa. Here, on the basis of first-principles simulations, we find that P-atom doping can effectively reduce the synthesis pressure of BP-N and maintain its stability at 0 GPa. Uniform distribution of P-atom dopants within BP-N layers helps maintain the structural stability of these layers at 0 GPa, while interlayer electrostatic interaction induced by N–P dipoles enhances dynamic stability by eliminating interlayer slipping. Furthermore, pressure is conducive to enhancing the stability of BP-N and its doped forms by suppressing N-chain dissociation. For a configuration with 12.5% doping concentration, a gravimetric energy density of 8.07 kJ/g can be realized, which is nearly twice that of trinitrotoluene.

Strong multi-kilotesla magnetic fields have various applications in high-energy density science and laboratory astrophysics, but they are not readily available. In our previous work [Y. Shi et al., Phys. Rev. Lett. 130, 155101 (2023)], we developed a novel approach for generating such fields using multiple conventional laser beams with a twist in the pointing direction. This method is particularly well-suited for multi-kilojoule petawatt-class laser systems like SG-II UP, which are designed with multiple linearly polarized beamlets. Utilizing three-dimensional kinetic particle-in-cell simulations, we examine critical factors for a proof-of-principle experiment, such as laser polarization, relative pulse delay, phase offset, pointing stability, and target configuration, and their impact on magnetic field generation. Our general conclusion is that the approach is very robust and can be realized under a wide range of laser parameters and plasma conditions. We also provide an in-depth analysis of the axial magnetic field configuration, azimuthal electron current, and electron and ion orbital angular momentum densities. Supported by a simple model, our analysis shows that the axial magnetic field decays owing to the expansion of hot electrons.

We present experimental results on kilojoule ultraviolet laser output with 1% spectral broadening. Through stimulated rotational Raman scattering (SRRS) with signal laser injection, we achieve effective spectral broadening in short-range propagation, with good retention of the original near-field distribution and time waveform. Theoretical calculations show that 2% bandwidth spectral broadening can be achieved by injecting 20 kW/cm2 signal light at 2.2 GW/cm2 flux of the pump laser. In addition, high-frequency modulation in the near field can be effectively avoided through replacement of the original random noise signal light by the controllable signal light. The SRRS in the atmospheric environment excited with signal laser injection can provide wide-band light output with controllable beam quality without long-distance propagation, representing an important potential route to realization of broadband laser drivers.

The interaction of high-power laser pulses with undercritical foams produced by different techniques but with the same average density is studied at the PALS laser facility. The spatial–temporal evolution of X-ray emission is observed using an X-ray streak camera, electron and ion temperatures are measured by X-ray spectroscopy, and hot-electron production is characterized by monochromatic X-ray imaging. Transmission of a femtosecond laser probe pulse through foams is observed in the near and far fields. In spite of large differences in pore size and foam structure, the velocity of ionization front propagation is quite similar for all the foams studied and is slower than that in a homogeneous material of the same average density. The ion temperature in the plasma behind the ionization front is a few times higher than the electron temperature. Hot-electron production in plastic foams with small pores is strongly suppressed compared with that in solid targets, whereas in foams produced by additive manufacturing, it is significantly increased to the level observed in bare copper foil targets.

Two-plasmon-decay instability (TPD) poses a critical target preheating risk in direct-drive inertial confinement fusion. In this paper, TPD collectively driven by dual laser beams consisting of a normal-incidence laser beam (Beam-N) and a large-angle-incidence laser beam (Beam-L) is investigated via particle-in-cell simulations. It is found that significant TPD growth can develop in this regime at previously unexpected low laser intensities if the intensity of Beam-L exceeds the large-angle-incidence threshold. Both beams contribute to the growth of TPD in a “seed-amplification” manner in which the absolute instability driven by Beam-L provides the seeds that are convectively amplified by Beam-N, making TPD energetically important and causing significant pump depletion and hot-electron generation.

Comprehensive understanding of the direct transformation pathway from graphite to diamond under high temperature and high pressure has long been one of the fundamental goals in materials science. Despite considerable experimental and theoretical progress, current experimental studies have mainly focused on the local microstructural characterizations of recovered samples, which has certain limitations for high-temperature and high-pressure products, which often exhibit diversity. Here, we report on the pressure-induced phase transition behavior of natural single-crystal graphite under three distinct pressure-transmitting media from a macroscopic perspective using in situ two-dimensional Raman spectroscopy, scanning electron microscopy, and atomic force microscopy. The surface evolution process of graphite before and after the phase transition is captured, revealing that pressure-induced surface textures can impede the continuity of the phase transition process across the entire single crystal. Our results provide a fresh perspective for studying the phase transition behavior of graphite and greatly deepen our understanding of this behavior, which will be helpful in guiding further high-temperature and high-pressure syntheses of carbon allotropes.

This study uses nonequilibrium molecular dynamics simulations to explore the dynamic failures and deformation mechanisms of a cylindrical shell composed of nanocrystalline nickel–titanium alloy under implosion loading. We discover that some individual spall planes are sequentially generated in the material along the propagation of a radial stress wave, indicative of the formation of multiple spallation. For larger grain sizes, void nucleation at the first spallation occurs in a coexisting intergranular/transgranular manner, whereas with decreasing grain size, voids tend to nucleate along the grain boundaries. Correspondingly, the spall strength exhibits a transition from an inverse Hall–Petch to a Hall–Petch relationship. For larger grain sizes, at the secondary spallation, localized shearing zones and grain boundaries provide potential void-nucleated sites. Importantly, the formation of shear deformation bands promotes grain refinement, contributing to a reduction in the dislocation-induced strengthening effect. Consequently, a lower spall strength is produced, in contrast to the first spallation. As the grain size becomes smaller, voids nucleate mostly along grain boundaries, and plastic deformation is dominated by dense grain boundaries. Overall, the high temperature caused by shear localization leads to material weakening, and in turn there is a significant decrease in the spall strength for the secondary spallation, compared with the first. Finally, significant penetration between two spall planes is observed for large grain size, which can be attributed to the nucleation of voids on linking grain boundaries, with temperatures exceeding the melting point of the material.

We report on commissioning experiments at the high-energy, high-temperature (HHT) target area at the GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, combining for the first time intense pulses of heavy ions from the SIS18 synchrotron with high-energy laser pulses from the PHELIX laser facility. We demonstrate the use of X-ray diagnostic techniques based on intense laser-driven X-ray sources, which will allow probing of large samples volumetrically heated by the intense heavy-ion beams. A new target chamber as well as optical diagnostics for ion-beam characterization and fast pyrometric temperature measurements complement the experimental capabilities. This platform is designed for experiments at the future Facility for Antiproton and Ion Research in Europe GmbH (FAIR), where unprecedented ion-beam intensities will enable the generation of millimeter-sized samples under high-energy-density conditions.

High-pressure synthesis of lutetium hydrides from molecular hydrogen (H2) and lutetium (Lu) is systematically investigated using synchrotron X-ray diffraction, Raman spectroscopy, and visual observations. We demonstrate that the reaction pathway between H2 and Lu invariably follows the sequence Lu ⟶ LuH2 ⟶ LuH3 and exhibits a notable time dependence. A comprehensive diagram representing the formation and synthesis of lutetium hydrides as a function of pressure and time is constructed. Our findings indicate that the synthesis can be accelerated by elevated temperature and decelerated by increased pressure. Notably, two critical pressure thresholds at ambient temperature are identified: the synthesis of LuH2 from Lu commences at a minimum pressure of ∼3 GPa, while ∼28 GPa is the minimum pressure at which LuH2 fails to transform into LuH3 within a time scale of months. This underscores the significant impact of temporal factors on synthesis, with the reaction completion time increasing sub-linearly with rising pressure. Furthermore, the cubic phase of LuH3 can be obtained exclusively through compressing the trigonal LuH3 phase at ∼11.5 GPa. We also demonstrate that the bandgap of LuH3 slowly closes under pressure and is noticeably lower than that of LuH2.