Dynamic compressive properties of mortar under inertial confinement: Experimental and numerical investigations

Rapid and non-invasive identification of the AFB1 contaminated peanut by data fusion of hyperspectral imaging and laser induced fluorescence

Sputter deposition of ultrathick Bi coatings onto rotating substrates for inertial confinement fusion

LIBS matrix effect deviation compensation through acoustic-optical spectra fusion LIBS technique.

Powder Bed Fusion–Laser Beam (PBF-LB) has emerged as a leading additive manufacturing technique for producing complex metallic components; however, its susceptibility to process-induced defects, particularly porosity, continues to limit its widespread application. In this study, a physics-informed computational framework was developed to predict porosity formation in Ti-6Al-4V parts by explicitly resolving transient thermal fields, melt pool dynamics, and layer-wise liquid fractions with temperature-dependent material properties. A dedicated graphical user interface was implemented, providing flexibility in defining the critical processing variables in PBF-LB. Model validation was performed using experimentally reported datasets from the literature. Benchmarking against melt pool geometries demonstrated that the algorithm successfully reproduced the depth and width evolution under different laser powers (100–195 W) and scan speeds (500–750 mm/s). Further comparisons with porosity data revealed strong quantitative consistency: for example, a numerical prediction of 0.19% porosity closely matched Archimedes (0.115%) and µ-CT (0.070%) results, while micrograph-based measurements indicated a higher value (0.204%). Across all investigated specimens, the algorithm reliably reflected experimentally observed porosity trends, including near fully dense conditions (

A reflective in-fiber liquid microsphere whispering gallery mode (WGM) resonator based on a Y-waveguide coupler is proposed and experimentally demonstrated. The sphere resonator is introduced inside a single-mode fiber (SMF) by using femtosecond laser micromachining and fusion splicing. A Y-waveguide coupler is fabricated with femtosecond laser direct writing, which is used to simultaneously excite and collect the WGM field through evanescent field coupling. High-index liquids are filled into the sphere through a laser-drilled channel to form a liquid microsphere where the WGM resonation takes place. The WGM resonator is sensitive to the refractive index (RI) of the filled liquids, and a RI sensitivity of 439 nm/RIU is achieved in an index range from 1.672 to 1.692. The liquid microsphere resonator is also sensitive to temperature, with a sensitivity of −307.1 pm/°C obtained. The microsphere resonator is small in size and robust, which has broad application prospects in the field of food and the chemical industry.

The publisher's note contains a correction to [ Opt. Express 33 , 46456 ( 2025 ) 10.1364/OE.575048 ]. The article was corrected on 17 December 2025.

Understanding the properties of warm dense hydrogen is of key importance for the modeling of compact astrophysical objects and to understand and further optimize inertial confinement fusion applications. The workhorse of warm dense matter theory is thermal density functional theory (DFT), which, however, suffers from two limitations: (i) its accuracy can depend on the utilized exchange–correlation functional, which has to be approximated, and (ii) it is generally limited to single-electron properties such as the density distribution. Here, we present a new ansatz combining time-dependent DFT results for the dynamic structure factor See(q, ω) with static DFT results for the density response. This allows us to estimate the electron–electron static structure factor See(q) of warm dense hydrogen with high accuracy over a broad range of densities and temperatures. In addition to its value for the study of warm dense matter, our work opens up new avenues for the future study of electronic correlations exclusively within the framework of DFT for a host of applications.

The measured fusion reaction history is a combination of the temporal evolution of the fusion hot spot temperature, mass, and volume. Depending on the mechanism of evolution in inertial confinement fusion implosions—shocks, compression, convergence, mass ablation, ignition—the evolution of the reaction history varies. Here, we derive and catalog a set of simplified inertial confinement fusion hot spot models with analytic solutions to infer the evolution of the fusion reaction history for each mechanism. The models give valuable insight into the meaning and cause of fusion reaction history and nuclear burnwidth measurements.

Several architectural concepts of petawatt optical drivers required for the commercialization of electrical power generated by laser fusion rely on the temporal compression of ultraviolet laser pulses by stimulated Brillouin scattering (SBS). For the design of SBS pulse compressors, precise measurements of the SBS gain spectrum and the strength of coupling between the pump and seed laser pulses are critical but not available. To that end, high-resolution measurements of the SBS gain spectral profiles and absolute coupling coefficients for Ar, Kr, and N2 in the ultraviolet are reported here. The SBS spectra recorded at 266 nm with <90 MHz resolution are in general agreement with the predictions of kinetic theory (Boltzmann–BGK model) over the entire 1–6 atm pressure range investigated, whereas hydrodynamic theory (Navier–Stokes model) describes neither the observed spectral profiles nor the coupling coefficients. At one atmosphere, the peak coupling coefficients predicted by the hydrodynamic theory for the rare gases Kr, Ar, and Ne are factors of 5–13 lower than those predicted by the kinetic theory. The success of kinetic theory models in accurately predicting SBS gain spectra opens a new parameter space for the design of high-energy Brillouin amplifiers for laser fusion drivers.

On the relation between microstructure and impact toughness of 17-4 PH stainless steel produced by powder bed fusion laser beam (PBF-LB)

Abstract Laser direct-drive liquid deuterium-tritium (DT) wetted foam capsules hold substantial promise for future advancements in inertial confinement fusion (ICF). For this new class of ICF capsules, additive manufacturing (AM) techniques are used to create low aspect ratio spherical shells of a low-density, foam-like CH lattice, which is wetted with cryogenic liquid DT. In the present paper, we discuss key physics issues intrinsic to ignition and burn propagation in laser direct drive wetted foam (LDD-WF) capsules. These include requirements on laser energy and power, implosion velocity, fuel adiabat, and initial density and dimensions of the CH lattice shell.

Abstract With signal levels increasing in inertial confinement fusion (ICF) facilities, attention is being applied to the prevention of saturation in the microchannel plate (MCP) photomultiplier tubes (PMTs), which are a key component in gamma and neutron detection diagnostics. We present three alternative strategies for the mitigation of saturation. The first is the dynamic modulation of the electron gain of the PMT, allowing the gain to be adjusted during the ICF event and therefore to time the linear response of the detector to coincide with the chosen region of interest while having some level of detection during the whole event. This contrasts with fast photocathode gating which only allows a binary on/off option. The second strategy is to use a segmented photocathode with three independently gated sections of the active area. These areas vary significantly in size to limit the saturation during the three different time gating windows. The third method is to reduce the volume of fused silica in the input window and hence diminish the levels of Chernkov-induced background signal. Finally we discuss timing improvements through the use of experimental 2 µm pore MCPs.

Microstructured foams are emerging as a promising class of targets, with applications ranging from laser-driven particle acceleration to inertial confinement fusion. To unlock their full potential, a deeper understanding of their properties, especially the changes and behavior of the microstructure under extreme conditions, is required. While recently advancing 3D printed foam targets can be observed by X-ray radiography, the microstructure in chemically produced targets is far below the spatial resolution of conventional radiography. To overcome this limitation, we apply grating-based X-ray dark-field imaging to observe structural changes in foams that are rapidly heated by laser-accelerated proton pulses. The experimental data is compared to synthetic dark-field values obtained from hydrodynamic simulations of a simplified foam model. Both experimental and simulation results demonstrate the viability of utilizing grating-based dark-field imaging for observing microstructural changes in foam targets.

The evolution mechanisms and suppression strategy of the Richtmyer–Meshkov instability (RMI) at heavy–light interfaces with varying Atwood numbers accelerated by two co-propagating shock waves are investigated through theoretical analysis and experimental evaluation. Existing models describing the complete evolution of once-shocked interfaces and the linear growth of twice-shocked interfaces are examined across low, moderate and high Atwood number regimes, and further refined based on detailed analyses of their limitations. Furthermore, an analytical model for describing the complete evolution of a twice-shocked interface (DS model) is developed through a comprehensive consideration of the shock-compression, start-up, linear and weakly nonlinear evolution processes. The combination of the refined models and DS model enables, for the first time, an accurate prediction of the complete evolution of interfaces subjected to two co-propagating shock waves. Building upon this, the parameter conditions required to manipulate the RMI with varying Atwood numbers are identified. Verification experiments confirm that suppressing the RMI growth at interfaces with various Atwood numbers via a same-side reshock is feasible and predictable. The present study may shed some light on strategies to suppress hydrodynamic instabilities in inertial confinement fusion through integrated adjustment of material densities and shock timings.

Amorphous carbon is an attractive material for next-generation inertial confinement fusion (ICF) ablators due to its amorphous structure, tunable density, compatibility with dopants, chemical inertness, and mechanical robustness. Ablators are typically deposited as ultrathick (10–200 μm) coatings on removable spherical templates. The deposition of such thick amorphous carbon films is challenging due to high intrinsic compressive stress, which causes film buckling and delamination. Here, we study the deposition of amorphous carbon films by magnetized, radiofrequency-driven hollow cathode chemical vapor deposition with a custom-designed source in Ne plasmas. Emphasis is on the hollow-cathode source design and effects of the plasma discharge power and the precursor flow rate on film properties. We demonstrate deposition rates of >1 μm/h for films with hydrogen content of ∼40 at. %, densities of 1.1–1.7 g/cm3, and trace quantities of oxygen impurities. We also demonstrate the feasibility of depositing thick hydrogenated amorphous carbon films (∼30 μm) for ICF applications.

Backscattering due to laser plasma instabilities (LPIs) presents a risk in the laser-driven inertial confinement fusion. Generally, it is assumed that the backscattering of laser beams in the same cone is identical in hohlraum physics studies. In the experiments performed at SG-100kJ laser facility, we find that the backscattering of laser beams in the same cone are quite different. Our investigation reveals the main reason for this phenomenon is that the laser beams in the same cone obtain different power from their neighbor beams via crossed-beam energy transfer (CBET) depending on their polarizations. The dependence of multi-beam CBET on laser polarization arrangement is confirmed in a specially designed experiment. These findings are crucial for understanding the backscattering, CBET, energy deficit and the azimuthal drive asymmetry in cylindrical hohlraums.

For a deuterium-tritium (D-T) fusion facility like Commonwealth Fusion Systems’ ARC or Xcimer Energy’s HYLIFE-III to operate at scale, considering that the current global tritium inventory is estimated at less than 27 kilograms1 compared to estimated start-up requirements alone (~10kg)1, it is clear that the viability of D-T fusion depends on the development of technologies that close the tritium fuel cycle. For instance, assuming cycle energies for the HYLIFE-III system, one day’s worth of 3 GJ fusion events at a 0.75Hz repetition rate2 would burn approximately 343.5 grams of tritium before including additional requirements to cover operational inefficiencies, radioactive decay (t1/2 = 12.32 years), or build a reserve inventory. Therefore, upcoming fusion facilities are planned to include "tritium breeding blankets", which generate the isotope through neutron capture reactions on lithium-6.The molten salt 2LiF-BeF2 (or FLiBe) is an attractive candidate for use as a liquid breeder. It combines a favorable neutron economy from the inclusion of beryllium as a neutron multiplier with compatibility as a heat transfer fluid to transport fusion energy to power generation at a relatively low corrosivity. However, a major research gap between today and the eventual scale-up of nuclear fusion facilities is the wide spread in the reported solubilities and diffusivities of tritium atoms (ions or otherwise) in FLiBe3, hindering the development of predictive engineering models for tritium retention, release, and accountancy.To address this, we will examine the behavior of hydrogen species in molten halides to build a mechanistic understanding of how a selected behavior depends on an equilibrium for or perturbation of a specific salt chemistry. We will review the body of literature examining hydrogen species (H-, Ho, and H+ of any isotope) behavior in the molten halides to assess how the cationic and anionic environments about hydrogen affect the solubility mechanisms and transport properties. Finally, we will extend this understanding to analyze the possible bond characteristics in Tritium-FLiBe systems incorporating the most recent electrochemical measurements of hydrogen speciation in FLiBe collected within the SALT group.We also reflect on strategies for communicating these complex chemical concepts to experts in other fields besides molten salts and ionic liquids. For example, words like species, behavior, or salt chemistry communicate a group of concepts to a reader which we cannot assume has the context to convert this terminology to actionable understandings to be implemented within system design of molten salt-facing technology. The behavior of hydrogen in molten FLiBe is not just a chemical curiosity; it directly impacts tritium safety, accountability, and supply. For these difficult to study systems (be it from the HF hazards, high temperatures, or strict beryllium safety protocols), it is important we make these chemical concepts accessible to the broader nuclear engineering community and extract as much value as possible from every measurement.To bridge the research and communication gaps, we propose a method to identify the excess chemical potential wells likely relevant to tritium-FLiBe chemistry like charge-dipole bonding between HF(d) and F-, BeF4 2-, or larger anions formed from tetrahedral crosslinking4 or covalent bonding character between elemental hydrogen and electropositive metals present in the melt. Using this method, we will define specific activity coefficients which relate input parameters (the exact LiF to BeF2 ratio, redox control additives, and tritium production rates) to the observed activities of T2 and TF in the melt from hypothetical tritium extraction rates for permeator or sparger systems. By demonstrating how the currently unpredictable data from tritium-FLiBe systems emerges from the chemistry at play in molten salts, we will build a case for molten salt chemical analysis as a core capability for fusion facilities through our exploration of charge-dipole and covalent bonding in our data and the body of literature on hydrogen-containing halide melts.(1) Abdou, M.; Riva, M.; Ying, A.; Day, C.; Loarte, A.; Baylor, L. R.; Humrickhouse, P.; Fuerst, T. F.; Cho, S. Physics and Technology Considerations for the Deuterium–Tritium Fuel Cycle and Conditions for Tritium Fuel Self Sufficiency. Nucl. Fusion 2020, 61 (1), 013001. https://doi.org/10.1088/1741-4326/abbf35.(2) Ogando, F.; Tobin, M. T.; Meier, W. R.; Farga-Niñoles, G.; Marian, J.; Reyes, S.; Sanz, J.; Galloway, C. Preliminary Nuclear Analysis of HYLIFE-III: A Thick-Liquid-Wall Chamber for Inertial Fusion Energy. Fusion Eng. Des. 2024, 202, 114333. https://doi.org/10.1016/j.fusengdes.2024.114333.(3) Humrickhouse, P. W.; Fuerst, T. F. Tritium Transport Phenomena in Molten-Salt Reactors; INL/EXT-20-59927-Rev000; Idaho National Lab. (INL), Idaho Falls, ID (United States), 2020. https://www.osti.gov/biblio/1777267 (accessed 2025-02-05).(4) Baes, C. F. A Polymer Model for BeF2 and SiO2 Melts. J. Solid State Chem. 1970, 1 (2), 159–169. https://doi.org/10.1016/0022-4596(70)90008-3.

Implosion symmetry represents a critical parameter governing compression efficiency and is closely linked to radiation-driven asymmetry, laser-plasma instabilities, and hydrodynamic instabilities. The evolution of asymmetry during early implosion phases impacts compression performance yet remains experimentally challenging to quantify. In this work, a wide-angle velocity interferometer system for any reflector (VISAR) was employed to diagnose the compression dynamics during the initial stage of indirect-drive implosions. Two experimental configurations—focused on total laser energy control and laser energy distribution control—were implemented to validate the diagnostic capabilities of the wide-angle VISAR. At 3 kJ drive energy, the wide-angle VISAR successfully resolved early shock transmission within the carbon hydrogen (CH) layer, with measured shock velocities of ~ 13 km/s. Under asymmetric drive conditions, the asymmetric evolution process of the capsule (P2) exhibited negative, near-linear growth within 0.5 ns, ultimately reaching ~ 30%. For higher drive energies (6.4 kJ), preheating effects induced a significant reduction in normalized reflectivity prior to shock arrival in the CH layer, resulting in irreversible fringe degradation within < 0.5 ns. These findings confirm the efficacy of wide-angle VISAR for diagnosing early-stage indirect-drive implosions. To extend its applicability, future development should focus on radiation-shielding architectures that enhance imaging robustness while mitigating preheating effects. Such advancements will enable operation at ignition-relevant energies, establishing wide-angle VISAR as a pivotal diagnostic tool for inertial confinement fusion research.

We present a class of self-similar solutions describing ultrahigh compression of a uniform-density target by spherically converging, stacked shock waves. Extending the classical Guderley model, we derive a scaling law for the final density of the form ρ_{r}/ρ_{0}∝P[over ̂]^{β(N-1)}, where N is the number of shocks, P[over ̂] the stage pressure ratio, and β a numerical exponent determined by the adiabatic index γ. One-dimensional hydrodynamic simulations confirm the validity of this scaling across a broad parameter range. Notably, the relation remains accurate even in the strongly nonlinear regime up to P[over ̂]∼70, well beyond the perturbative limit, highlighting the robustness and practical relevance of the model. Owing to its volumetric geometry, this compression scheme inherently avoids the Rayleigh-Taylor instability, which typically compromises shell-based implosions, and thereby establishes a theoretical benchmark for instability-free compression in inertial confinement fusion.