The High Explosives & Affected Targets (HEAT) Dataset
Physics-rich dataset of cylindrically symmetric shock-propagation simulations (CYL and PLI).
97 MATHEMATICS AND COMPUTING↗
SEARCH · Engineering Papers
Results for “shock physics”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Acoustic Observations of the OSIRIS-REx Sample Return Capsule Re-Entry from Wendover Airport
The Origins, Spectral Interpretation, Resource Identification, and Security‐Regolith Explorer sample return capsule (SRC) re‐entered the Earth’s atmosphere at hypersonic speeds from interplanetary space on 24 September 2023. The current work reports on 18 ground‐based acoustic sensors deployed at Wendover Airport, the same location that the Genesis and Stardust SRC re‐entries were recorded. Four different sensors (Chaparral Physics, Gem, Wilson Engineering Research and Development [WERD], and RedVox) were deployed in close proximity to compare their performance. All the sensors captured an N‐wave signal associated with the SRC re‐entry shock wave followed by a broadband coda. The Chaparral Physics array served as the high‐fidelity reference measurement. The N‐wave signal had a peak‐to‐peak amplitude of 4.07 Pa with a fundamental frequency of 4.98 Hz from 167.5° measured clockwise from north, nearly perpendicular to the SRC trajectory. In addition, high coherence in the coda was shown to be associated reflections from the surrounding mountains. In general, the more economical sensors (Gem, WERD, and RedVox) produced results that were consistent with these observations and sensor specifications. Beamforming with these single sensors arranged as an array showed agreement with the high‐fidelity array to within a couple of degrees. Furthermore, the current high‐fidelity results were compared with the measurements during the Genesis and Stardust SRC re‐entries. All three entries produced a broadband fundamental peak at a frequency that was inversely related to the SRC diameter as well as evidence of reflections from the surrounding topography.
KC, Real J. [Oklahoma State University, Stillwater↗
Energy localization efficiency in 1,3,5-trinitro-2,4,6-triaminobenzene pore collapse mechanisms
Atomistic and continuum scale modeling efforts have shown that the shock-induced collapse of porosity can occur via a wide range of mechanisms dependent on pore morphology, the shockwave pressure, and material properties. The mechanisms that occur under weaker shocks tend to be more efficient at localizing thermal energy but do not result in high, absolute temperatures or spatially large localizations compared to mechanisms found under strong shock conditions. However, the energetic material 1,3,5-trinitro-2,4,6-triaminobenzene (TATB) undergoes a wide range of collapse mechanisms that are not typical of similar materials, leaving the collapse mechanisms and the resultant energy localization from the collapse, i.e., hotspots, relatively uncharacterized. Therefore, we present the pore collapse simulations of cylindrical pores in TATB for a wide range of pore sizes and shock strengths that trigger viscoplastic collapses that occur almost entirely perpendicular to the shock direction for weak shocks and hydrodynamic-like collapses for strong shocks that do not break the strong hydrogen bonds of the TATB basal planes. The resulting hotspot temperature fields from these mechanisms follow trends that differ considerably from other energetic materials; hence, we compare them under normalized temperature values to assess the relative efficiency of each mechanism to localize energy. The local intra-molecular strain energy of the hotspots is also assessed to better understand the physical mechanisms behind the phenomena that lead to a latent potential energy.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Efficient generation of turbulent collisionless shocks in laser-ablated counter-streaming plasmas
Not Available
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Laser driven shocks in the Large Plasma Device (Final Report)
We present an overview of the key findings of the laser-shock experiments on the LAPD funded by the NSF/DOE award in plasma science.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Inherent issues regarding the use of in situ x-ray diffraction measurements to determine temperature in shock-compressed metals
Temperature determination in shock compressed solids constitutes an important and long-standing scientific need. Since the reduction of Bragg diffracted peaks due to temperature increase, using the Debye-Waller factor, is well established, we examined the use of this approach to determine temperatures in shock compressed gold and platinum by representing the shocked state as a superposition of density and temperature changes. Comparison of the calculated and measured diffraction peaks did not show good agreement, because x-ray diffraction (XRD) profiles in the shock compressed state are not governed solely by density and temperature changes. XRD results are also influenced measurably by shock wave induced microstructural changes. Our results demonstrate that contributions from microstructural changes need to be incorporated and modeled in the theoretical analysis to use XRD measurements for reliable temperature determination in shock compressed solids.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Shocking Cerium into a New Phase
A material's equation of state (EOS) - which indicates its state under various conditions of pressure, temperature, volume, and energy, and relates them to various phases - is a vital part of understanding the material’s behavior and response in different environments and applications. However, determining the EOS and complete phase diagrams of some materials can pose daunting challenges. One of these materials is cerium, for which some regions of the phase diagram have proven elusive. Investigators from the U.S. Department of Energy’s (DOE’s) Los Alamos National Laboratory (LANL) employed the U.S. DOE’s Advanced Photon Source (APS) to probe the high-pressure solid phase of cerium through shock-wave experiments that provided a detailed look at the cerium's transition from the α-ϵ phases. Their work, which provides the first evidence that an α-ϵ phase transition can be shock-induced in cerium, was published in the Journal of Applied Physics.
36 MATERIALS SCIENCE↗
Solitary Magnetic Structures at Quasi–Parallel Collisionless Shocks: Formation
Solitary magnetic structures known as SLAMS (short large-amplitude magnetic structures) have been considered as essential elements of collisionless shocks with quasi-parallel geometries. Yet the physics underlying their formation remains an open question. In this paper, we use measurements from the magnetospheric multiscale mission combined with fully kinetic simulations to study the formation of SLAMS. We find that gyro-resonance between solar wind ions and right-hand circularly polarized electromagnetic waves results in magnetic field amplification. Gyro-trapping by the growing magnetic field builds up the plasma density that further enhances the current and field. The solitary nature of SLAMS stems from a beat-like magnetic field envelope where the maximum sets the initial location for nonlinear growth. Our results present a conceptual advance on SLAMS, and may shed new light on the open question of magnetic field amplification at astrophysical shocks.
58 GEOSCIENCES↗
Generation of shock trains in free liquid jets with a nanosecond green laser
Shock wave trains in liquid jets were previously generated only by ablation with femtosecond x-ray lasers. Here we show that shock trains in water microjets can be also generated using nanosecond green laser pulses with 1- to 10-mJ energy. Furthermore, the ablation of 15-, 20-, 30-, and 70-μm water microjets opened a gap in the jets and launched an initial shock wave. Fully developed shock trains were observed in the 30- and 70-μm jets up to 250-ns delays, and these trains were also transmitted inside the nozzles. A few tens of nanoseconds after the pulse, the shock dynamics and its pressure became similar to the ones generated by x-ray lasers, with a more rapid pressure decay in thinner jets. At time delays exceeding 100 ns in the 30-μm jets, the leading shock pressure stabilized to an approximately constant pressure of 40 MPa. The energy density deposited in the jets was estimated at 30 MJ/cm 3 by comparing the jet gaps in the green and x-ray laser experiments, and matched previous estimates for optical ablation in water. Here, the pressure decay in the 30-μm jets was modeled based on the pressure decay observed in x-ray laser experiments.
74 ATOMIC AND MOLECULAR PHYSICS↗
Modeling Hydrodynamic Instabilities, Shocks, and Radiation Waves in High Energy Density Experiments [Slides]
Abstract not provided.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Rapid activation of non-oriented mechanophores via shock loading and spallation
Mechanophores (MPs), stimuli-responsive molecules that respond chromatically to mechanochemical reactions, are important for understanding the coupling between mechanics and chemistry as well as in engineering applications. However, the atomic-level understanding of their activation originates from gas phase studies or under simple linear elongation forces directly on molecules or polymer chains containing MPs. The effect of many-body distortions, pervasive in condensed-phase applications, is not understood. Therefore, we performed large-scale molecular dynamics (MD) simulations of a poly(methyl methacrylate)-spiropyran copolymer under dynamic mechanical loading and studied the activation of the MP under various conditions from dynamical compression to tension during unloading. Detailed analysis of the all-atom MD trajectories shows that the MP blocks experience significant many-body intramolecular distortion that can significantly decrease the activation barrier as compared with when deformation rates are slow relative to molecular relaxation time scales. Here we find that the reactivity of MPs under material compression states is governed by many-body effects of intramolecular torsions, whereas under tension, the reactions are governed by tensile stresses.
36 MATERIALS SCIENCE↗
Peening Techniques for Surface Modification: Processes, Properties, and Applications
Surface modification methods have been applied to metals and alloys to change the surface integrity, obtain superior mechanical properties, and improve service life irrespective of the field of application. In this review paper, current state-of-the-art of peening techniques are demonstrated. More specifically, classical and advanced shot peening (SP), ultrasonic impact peening (UIP), and laser shock peening (LSP) have been discussed. The effect of these techniques on mechanical properties, such as hardness, wear resistance, fatigue life, surface roughness, and corrosion resistance of various metals and alloys, are discussed. This study also reports the comparisons, advantages, challenges, and potential applications of these processes.
microstructure↗
Influences of shock imprinting on mix in a 3D-printed porous media
Mixing of materials in porous media can cause a significant impact on fusion yield as previously demonstrated by the National Ignition Facility (NIF) MARBLE Campaign. Initially, the reactants are separated, with deuterium in the lattice struts and a tritium gas fill in the voids. Lattice parameters such as the strut thickness and relative pitch, provide a control for the mix parameters in the experiment. Los Alamos National Laboratory’s (LANL) BOSQUE project looks to better understand how the mix of the reactants and shell materials impact the fusion burn and resultant yield on various laser platforms. xRAGE’s Eulerian hydrodynamics and adaptive mesh refinement (AMR) provide the unique ability to study the impacts of multiscale features of complex lattice structures. This modeling provides the ability to measure shock front variations as the wave progress’ through a given media. Initial conditions of the lattice are essential to accurately model mix and burn measured by experiment. By varying the initial orientation and densities of these lattice regions the early time dynamics of how the shock is launched into the system is changed and advocates for the study of resulting effects. In this work, we will study the sensitivities of shock effects in varying 3D printed geometric systems and how these shocks alter the structure and mix in the lattice. We will discuss both preliminary experimental results and simulations to help plan and constrain future experiments where we will study the impact of different lattice geometries and lattice bulk densities. This work concludes with the relative impacts of lattice geometries on shock speeds at different bulk densities and the resultant mix widths due to those shock interactions. We see agreement with theory at the higher end of our bulk density study, however, as we approach lower bulk density systems the dynamics of these interactions begin to change.
2 Photon Polymerization↗
Interaction of Inner Heliosheath Ions with Electromagnetic Ion Cyclotron Waves
Abstract Inner heliosheath (IHS) ions are expected to be exposed to various waves, shocks, and turbulence, which can affect ion distributions and thus their charge-exchange rates with interstellar neutral atoms. This work addresses the potential significance of electromagnetic ion cyclotron (EMIC) waves under expected IHS conditions. From a kinetic dispersion relation, we find the possibility of frequent triggering of EMIC instability in the IHS. The threshold anisotropy of proton temperatures required for the instability is small, ( T ⊥ – T ∣∣ )/ T ∣∣ ≈ 0.1 or less, mainly due to high plasma β (ratio of the plasma to magnetic pressures). Numerical calculations on the scattering of ions (protons, He + , and He 2+ with energy of 0.01–50 keV) based on two models for EMIC waves with a moderate intensity indicate significant scattering in the pitch angle (mostly a few tens of degrees) and energy (mostly a few tens of percent) although details depend on the energy and pitch angle of each species and adopted EMIC wave models. This occurs on a short timescale (<100 times the gyro-period of each ion species). Resonant scattering in a few to a few tens of keV (corresponding to the expected pickup ion energy in the IHS) is easily expected unless the wavenumber is too large. The scattering effect is distinguished among different species such that for lower gyrofrequency ions (He + versus He 2+ and He 2+ versus protons), the main scattering effect moves toward a lower energy domain. All these results imply continuous disturbance of ion distributions by possibly prevailing EMIC waves in the IHS.
79 ASTRONOMY AND ASTROPHYSICS↗
Stability of the fcc phase in shocked nickel up to 332 GPa
Despite making up 5-20 wt.% of Earth’s predominantly iron core, the melting properties of elemental nickel at core conditions remain poorly understood, due largely to a dearth of experimental data. We present here an in situ X-ray diffraction study performed on laser shock-compressed samples of bulk nickel, reaching pressures up to ~ 500 GPa. Hugoniot states of nickel were targeted using a flat-top laser drive, with in situ X-ray diffraction data collected using the Linac Coherent Light Source. Rietveld methods were used to determine the densities of the shocked states from the measured diffraction data, while peak pressures were determined using a combination of measured particle velocities, shock transit times, hydrodynamic simulations, and laser intensity calibrations. We observed solid compressed face-centered cubic (fcc) Ni up to at least 332 ± 30 GPa along the Hugoniot—significantly higher than expected from the majority of melt lines that have been proposed for nickel. We also bracket the partial melting onset to between 377 ± 38 GPa and 486 ± 35 GPa.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Variable-density buoyancy-driven turbulence with asymmetric initial density distribution
The effects of different initial density distributions on the evolution of buoyancy-driven homogeneous variable-density turbulence (HVDT) at low (0.05) and high (0.75) Atwood numbers are studied by using high-resolution direct numerical simulations. HVDT aims to mimic the acceleration-driven Rayleigh–Taylor and shock-driven Richtmyer–Meshkov instabilities and reveals new physics that arise from variable-density effects on the turbulent mixing. Here, the initial amounts of pure light and pure heavy flows are altered primarily to mimic the variable-density turbulence at the different locations of the Rayleigh–Taylor and Richtmyer–Meshkov instabilities’ mixing layers where the amounts of the mixing fluids are not equal. It is found that for the low Atwood number cases, the asymmetric initial density distribution has limited effects on both global and local flow evolution for HVDT. However, at high Atwood number, both global flow evolution and the local flow structures are strongly affected by the initial composition ratio. The flow composed of more light fluid reaches higher turbulent levels and the local statistics reach their fully-developed behavior earlier in the time evolution. In contrast, during the late time decay, where most of the flow is well-mixed, all parameters become independent of the initial composition ratio for both low and high Atwood number cases.
42 ENGINEERING↗
High-resolution Near-infrared Spectroscopic Study of Galactic Supernova Remnants. I. Kinematic Distances
We have carried out high-resolution near-infrared spectroscopic observations toward 16 Galactic supernova remnants (SNRs) showing strong H 2 emission features. A dozen bright H 2 emission lines are clearly detected for individual SNRs, and we have measured their central velocities, line widths, and fluxes. For all SNRs except one (G9.9–0.8), the H 2 line ratios are well consistent with that of thermal excitation at T ~ 2000 K, indicating that the H 2 emission lines are most likely from shock-excited gas and therefore that they are physically associated with the remnants. The kinematic distances to the 15 SNRs are derived from the central velocities of the H 2 lines using a Galactic rotation model. We derive for the first time the kinematic distances to four SNRs: G13.5+0.2, G16.0–0.5, G32.1–0.9, and G33.2–0.6. Among the remaining 11 SNRs, the central velocities of the H 2 emission lines for six SNRs are well consistent (±5 km s -1 ) with those obtained in previous radio observations, while for the other five SNRs (G18.1–0.1, G18.9–1.1, Kes 69, 3C 396, W49B) they are significantly different. We discuss the velocity discrepancies in these five SNRs. In G9.9–0.8, the H 2 emission shows nonthermal line ratios and narrow line width (~4 km s -1 ), and we discuss its origin.
79 ASTRONOMY AND ASTROPHYSICS↗
A Comparison of Raman and Pyrometry Dynamic Temperature Measurements of Shocked Cyclohexane
Article manuscript written by LANL primary authors with Lynn Veeser of MSTS (subcontractor) for consideration by Journal of Applied Physics.
36 MATERIALS SCIENCE↗