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  • Conference paper
    Nguyen TT, Masouros S, 2019,

    Penetration of Blast Fragments to the Thorax

    , International Research Council On Biomechanics Of Injury 2019
  • Conference paper
    Nguyen TT, Masouros S, 2019,

    Penetration of Blast Fragments to the Thorax

    , International Research Council On Biomechanics Of Injury
  • Journal article
    Hatfield P, Rose S, Scott R, 2019,

    The blind implosion-maker: Automated inertial confinement fusion experiment design

    , Physics of Plasmas, Vol: 26, ISSN: 1070-664X

    The design of inertial confinement fusion (ICF) experiments, alongside improving the development of energy density physics theory and experimental methods, is one of the key challenges in the quest for nuclear fusion as a viable energy source [O. A. Hurricane, J. Phys.: Conf. Ser. 717, 012005 (2016)]. Recent challenges in achieving a high-yield implosion at the National Ignition Facility (NIF) have led to new interest in considering a much wider design parameter space than normally studied [J. L. Peterson et al., Phys. Plasmas 24, 032702 (2017)]. Here, we report an algorithmic approach that can produce reasonable ICF designs with minimal assumptions. In particular, we use the genetic algorithm metaheuristic, in which “populations” of implosions are simulated, the design of the capsule is described by a “genome,” natural selection removes poor designs, high quality designs are “mated” with each other based on their yield, and designs undergo “mutations” to introduce new ideas. We show that it takes ∼5 × 104 simulations for the algorithm to find an original NIF design. We also link this method to other parts of the design process and look toward a completely automated ICF experiment design process—changing ICF from an experiment design problem to an algorithm design problem.

  • Conference paper
    Nguyen TT, Meek G, Masouros S, 2019,

    Blast Fragment Protection for The Extremities

    , Light Weight Armour for Defense & Security 2019
  • Journal article
    Derrick JG, Rutherford ME, Chapman DJ, Davison TM, Duarte JPP, Farbaniec L, Bland PA, Eakins DE, Collins GSet al., 2019,

    Investigating shock processes in bimodal powder compaction through modelling and experiment at the mesoscale

    , International Journal of Solids and Structures, Vol: 163, Pages: 211-219, ISSN: 0020-7683

    Impact-driven compaction is a proposed mechanism for the lithification of primordial bimodal granular mixtures from which many meteorites derive. We present a numerical-experimental mesoscale study that investigates the fundamental processes in shock compaction of this heterogeneous matter, using analog materials. Experiments were performed at the European Synchrotron Radiation Facility generating real-time, in-situ, X-ray radiographs of the shock's passage in representative granular systems. Mesoscale simulations were performed using a shock physics code and set-ups that were geometrically identical to the experiments. We considered two scenarios: pure matrix, and matrix with a single chondrule. Good agreement was found between experiments and models in terms of shock position and post-shock compaction in the pure powder setup. When considering a single grain embedded in matrix we observed a spatial porosity anisotropy in its vicinity; the compaction was greater in the region immediately shockward of the grain, and less in its lee. We introduced the porosity vector, C, which points in the direction of lowest compaction across a chondrule. This direction-dependent observation may present a new way to decode the magnitude, and direction, of a single shock wave experienced by a meteorite in the past.

  • Journal article
    Yanuka D, Rososhek A, Theocharous S, Bland SN, Krasik YE, Olbinado MP, Rack A, Oreshkin EVet al., 2019,

    X-ray radiography of the overheating instability in underwater electrical explosions of wires

    , Physics of Plasmas, Vol: 26, ISSN: 1070-664X

    We present the measurements of the development of striation like instabilities during the electrical driven explosions of wires in a waterbath. In vacuum based wire explosion experiments, such instabilities have long been known. However, in spite of intense research into theexplosion of wires in liquids, the development of these instabilities has either not been observed or has been assumed to play a minor role inthe parameters of the exploding wire due to the tamping of the wire’s explosion. Using synchrotron based multiframe radiography, we haveseen the development of platelike density structures along an exploding copper wire. Our measurements were compared to a 2Dmagnetohydrodynamics simulation, showing similar striation formation. These observed instabilities could affect the measurements of theconductivity of the wire material in the gas-plasma state—an important parameter in the warm dense matter community. The striationscould also act as a seed for other instabilities later in time if the wire is in a dense flow of material or experiences a shock from an adjacentwire—as it would do in experiments with arrays of wires.

  • Journal article
    Gould O, Mangles S, Rajantie A, Rose S, Xie Cet al., 2019,

    Observing thermal Schwinger pair production

    , Physical Review A, Vol: 99, ISSN: 1050-2947

    We study the possibility of observing Schwinger pair production enhanced by a thermal bath of photons. We consider the full range of temperatures and electric field intensities from pure Schwinger production to pure thermal production, and identify the most promising and interesting regimes. In particular, we identify temperatures of ∼ 20 keV/kB and field intensities of ∼ 10²³ W cm¯² where pair production would be observable. In this case, the thermal enhancement over the Schwinger rate is exponentially large and due to effects which are not visible at any finite order in the loop expansion. Pair production in this regime can thus be described as more nonperturbative than the usual Schwinger process, which appears at one loop. Unfortunately, such high temperatures appear to be out of reach of foreseeable technologies, though nonthermal photon distributions with comparable energy densities are possible. We suggest the possibility that similar nonperturbative enhancements may extend out of equilibrium and propose an experimental scheme to test this.

  • Journal article
    Yanuka D, Theocharous S, Efimov S, Bland SN, Rososhek A, Krasik YE, Olbinado MP, Rack Aet al., 2019,

    Synchrotron based X-ray radiography of convergent shock waves driven by underwater electrical explosion of a cylindrical wire array

    , Journal of Applied Physics, Vol: 125, ISSN: 0021-8979

    We present X-ray radiography images showing the propagation of shock waves generated by electrical explosion of a cylindrical arrangement of wires in water driven by pulsed power. In previous experiments [S. N. Bland et al., Phys. Plasmas 24, 082702 (2017)], the merger of shock waves from adjacent wires has produced a highly symmetrical, cylindrical shock wave converging on the axis, where it is expected to produce a high density, strongly coupled plasma ideal for warm dense matter research. However, diagnostic limitations have meant that much of the dynamics of the system has been inferred from the position of the front of the cylindrical shock and timing/spectra of light emitted from the axis. Here, we present a synchrotron-based radiography of such experiments—providing direct quantitative measurements on the formation of the convergent shock wave, the increased density of water on the axis caused by its arrival, and its “bounce” after arrival on the axis. The obtained images are compared with two-dimensional hydrodynamic simulations, which reproduce the observed dynamics with a satisfactory agreement in density values.

  • Journal article
    Pissarenko A, Yang W, Quan H, Brown KA, Williams A, Proud WG, Meyers MAet al., 2019,

    Tensile behavior and structural characterization of pig dermis

    , ACTA BIOMATERIALIA, Vol: 86, Pages: 77-95, ISSN: 1742-7061
  • Journal article
    Perez-Callejo G, Liedahl DA, Schneider MB, Rose SJ, Wark JSet al., 2019,

    The use of geometric effects in diagnosing ion density in ICF-related dot spectroscopy experiments

    , High Energy Density Physics, Vol: 30, Pages: 45-51, ISSN: 1574-1818

    We describe a method to calculate the ion density of High Energy Density (HED) cylindrical plasmas used in dot spectroscopy experiments. This method requires only spectroscopic measurements of the Heα region obtained from two views (Face-on and Side-on). We make use of the fact that the geometry of the plasma affects the observed flux of optically thick lines. The ion density can be derived from the aspect ratio (height-to-radius) of the cylinder and the optical depth of the Heα-y line (1s2p 3P1 → 1s2 1S0). The aspect ratio and the optical depth of the y line are obtained from the spectra using ratios measured from the two directions of emission of the optically thick Heα-w line (1s2p 1P1 → 1s2 1S0) and the ratio of the optically thick to thin lines. The method can be applied to mid-Z elements at ion densities of 1019– and temperatures of a the order of keV, which is a relevant regime for Inertial Confinement Fusion (ICF) experiments.

  • Journal article
    Nguyen T-T, Pearce AP, Carpanen D, Sory D, Grigoriadis G, Newell N, Clasper J, Bull A, Proud WG, Masouros SDet al., 2019,

    Experimental platforms to study blast injury

    , Journal of the Royal Army Medical Corps, Vol: 165, Pages: 33-37, ISSN: 2052-0468

    Injuries sustained due to attacks from explosive weapons are multiple in number, complex in nature, and not well characterised. Blast may cause damage to the human body by the direct effect of overpressure, penetration by highly energised fragments, and blunt trauma by violent displacements of the body. The ability to reproduce the injuries of such insults in a well-controlled fashion is essential in order to understand fully the unique mechanism by which they occur, and design better treatment and protection strategies to alleviate the resulting poor long-term outcomes. This paper reports a range of experimental platforms that have been developed for different blast injury models, their working mechanism, and main applications. These platforms include the shock tube, split-Hopkinson bars, the gas gun, drop towers and bespoke underbody blast simulators.

  • Journal article
    Theocharous SP, Bland SN, Yanuka D, Rososhek A, Olbinado MP, Rack A, Krasik YEet al., 2019,

    Use of synchrotron-based radiography to diagnose pulsed power driven wire explosion experiments

    , Review of Scientific Instruments, Vol: 90, ISSN: 0034-6748

    We describe the first use of synchrotron radiation to probe pulsed power driven high energy density physics experiments. Multi-frame x-ray radiography with interframe spacing of 704 ns and temporal resolution of <100 ps was used to diagnose the electrical explosion of different wire configurations in water including single copper and tungsten wires, parallel copper wire pairs, and copper x-pinches. Such experiments are of great interest to a variety of areas including equation of state studies and high pressure materials research, but the optical diagnostics that are usually employed in these experiments are unable to probe the areas behind the shock wave generated in the water, as well as the internal structure of the exploding material. The x-ray radiography presented here, performed at beamline ID19 at European Synchrotron Radiation Facility (ESRF), was able to image both sides of the shock to a resolution of up to 8 μm, and phase contrast imaging allowed fine details of the wire structure during the current driven explosion and the shock waves to be clearly observed. These results demonstrate the feasibility of pulsed power operated in conjunction with synchrotron facilities, as well as an effective technique in the study of shock waves and wire explosion dynamics.

  • Journal article
    Rutherford ME, Derrick JG, Chapman DJ, Collins GS, Eakins DEet al., 2019,

    Insights into local shockwave behavior and thermodynamics in granular materials from tomography-initialized mesoscale simulations

    , Journal of Applied Physics, Vol: 125, ISSN: 0021-8979

    Interpreting and tailoring the dynamic mechanical response of granular systems relies upon understanding how the initial arrangement of grains influences the compaction kinetics and thermodynamics. In this article, the influence of initial granular arrangement on the dynamic compaction response of a bimodal powder system (soda-lime distributed throughout a porous, fused silica matrix) was investigated through continuum-level and mesoscale simulations incorporating real, as-tested microstructures measured with X-ray tomography. By accounting for heterogeneities in the real powder composition, continuum-level simulations were brought into significantly better agreement with previously reported experimental data. Mesoscale simulations reproduced much of the previously unexplained experimental data scatter, gave further evidence of low-impedance mixture components dominating shock velocity dispersion, and crucially predicted the unexpectedly high velocities observed experimentally during the early stages of compaction. Moreover, only when the real microstructure was accounted for did simulations predict that small fractions of the fused silica matrix material would be driven into the β-quartz region of phase space. These results suggest that using real microstructures in mesoscale simulations is a critical step in understanding the full range of shock states achieved during dynamic granular compaction and interpreting solid phase distributions found in real planetary bodies.

  • Journal article
    Shelkovenko TA, Pikuz SA, Tilikin IN, Mitchell MD, Bland SN, Hammer DAet al., 2018,

    Evolution of X-pinch loads for pulsed power generators with current from 50 to 5000 kA

    , Matter and Radiation at Extremes, Vol: 3, Pages: 267-277, ISSN: 2468-080X

    A review of X-pinches of various configurations and of different materials as an X-ray source for various applications is presented. The advantages and disadvantages of different designs of X-pinches as a load for generators with a wide range of output parameters and as a source of X-ray radiation for X-ray point-projection imaging were analyzed.

  • Journal article
    McBride RD, Stygar WA, Cuneo ME, Sinars DB, Mazarakis MG, Leckbee JJ, Savage ME, Hutsel BT, Douglass JD, Kiefer ML, Oliver BV, Laity GR, Gomez MR, Yager-Elorriaga DA, Patel SG, Kovalchuk BM, Kim AA, Gourdain PA, Bland SN, Portillo S, Bott-Suzuki SC, Beg FN, Maron Y, Spielman RB, Rose DV, Welch DR, Zier JC, Schumer JW, Greenly JB, Covington AM, Steiner AM, Campbell PC, Miller SM, Woolstrum JM, Ramey NB, Shah AP, Sporer BJ, Jordan NM, Lau YY, Gilgenbach RMet al., 2018,

    A primer on pulsed power and linear transformer drivers for high energy density physics applications

    , IEEE Transactions on Plasma Science, Vol: 46, Pages: 3928-3967, ISSN: 0093-3813

    The objectives of this tutorial are as follows: 1) to help students and researchers develop a basic understanding of how pulsed-power systems are used to create high-energy-density (HED) matter; 2) to develop a basic understanding of a new, compact, and efficient pulsed-power technology called linear transformer drivers (LTDs); 3) to understand why LTDs are an attractive technology for driving HED physics (HEDP) experiments; 4) to contrast LTDs with the more traditional Marx-generator/pulse-forming-line approach to driving HEDP experiments; and 5) to briefly review the history of LTD technology as well as some of the LTD-driven HEDP research presently underway at universities and research laboratories across the globe. This invited tutorial is part of the Mini-Course on Charged Particle Beams and High-Powered Pulsed Sources, held in conjunction with the 44th International Conference on Plasma Science in May of 2017.

  • Journal article
    Yanuka D, Rososhek A, Theocharous S, Bland SN, Krasik YE, Olbinado MP, Rack Aet al., 2018,

    Multi frame synchrotron radiography of pulsed power driven underwater single wire explosions

    , Journal of Applied Physics, Vol: 124, ISSN: 0021-8979

    We present the first use of synchrotron-based phase contrast radiography to study pulsed-power driven high energy density physics experiments. Underwater electrical wire explosions have become of interest to the wider physics community due to their ability to study material properties at extreme conditions and efficiently couple stored electrical energy into intense shock waves in water. The latter can be shaped to provide convergent implosions, resulting in very high pressures (1-10 Mbar) produced on relatively small pulsed power facilities (100s of kA-MA). Multiple experiments have explored single-wire explosions in water, hoping to understand the underlying physics and better optimize this energy transfer process; however, diagnostics can be limited. Optical imaging diagnostics are usually obscured by the shock wave itself; and until now, diode-based X-ray radiography has been of relatively low resolution and rather a broad x-ray energy spectrum. Utilising phase contrast imaging capabilities of the ID19 beamline at the European Synchrotron Radiation Facility, we were able to image both the exploding wire and the shock wave. Probing radiation of 20-50 keV radiographed 200 μm tungsten and copper wires, in ∼2-cm diameter water cylinders with resolutions of 8 μm and 32 μm. The wires were exploded by a ∼30-kA, 500-ns compact pulser, and 128 radiographs, each with a 100-ps X-ray pulse exposure, spaced at 704 ns apart were taken in each experiment. Abel inversion was used to obtain the density profile of the wires, and the results are compared to two dimensional hydrodynamic and one dimensional magnetohydrodynamic simulations.

  • Journal article
    Magnus D, Khan MA, Proud WG, 2018,

    Epidemiology of civilian blast injuries inflicted by terrorist bombings from 1970-2016

    , DEFENCE TECHNOLOGY, Vol: 14, Pages: 469-476, ISSN: 2096-3459
  • Conference paper
    Nguyen TT, Carpanen D, Tear G, Stinner D, Clasper J, Proud W, Masouros Set al., 2018,

    Fragment Penetrating Injury to the tibia

    , Personal Armour Systems Symposia 2018
  • Journal article
    Zhang X, Wang G, Luo B, Tan F, Bland SN, Zhao J, Sun C, Liu Cet al., 2018,

    Refractive index and polarizability of polystyrene under shock compression

    , JOURNAL OF MATERIALS SCIENCE, Vol: 53, Pages: 12628-12640, ISSN: 0022-2461
  • Conference paper
    Butler BJ, Williams A, Tucker AW, Proud WG, Brown KAet al., 2018,

    Comparative quasi-static mechanical characterization of fresh and stored porcine trachea specimens

    , 12th International Conference of the European-Association-for-the-Promotion-of-Research-into-the-Dynamic-Behaviour-of-Materials-and-its-Applications (DYMAT-Association), Publisher: SPRINGER HEIDELBERG, Pages: 55-60, ISSN: 1951-6355
  • Journal article
    Shelkovenko TA, Pikuz SA, Tilikin IN, Bland SN, Lall D, Chaturvedi N, Georgakis Aet al., 2018,

    X-pinch X-ray emission on a portable low-current, fast rise-time generator

    , Journal of Applied Physics, Vol: 124, ISSN: 0021-8979

    We report on experiments exploring X-ray emission from an X-pinch driven by a small Marx-waterline generator supplying 50 kA with a risetime of 50 ns and a peak voltage of ∼250 kV. Both standard crossed wire loads and hybrid loads utilizing conical metal electrodes with a single short wire in between them were studied, and in both cases reliable modes of operation were obtained for X-ray radiography. Soft (few keV) and Hard (>5 keV) X-ray emission characteristics were observed. With standard X-pinches, soft radiation emanated from a small hot spot about 3 μm in size, along with hard radiation from a ∼200 μm region close to this hot spot. With hybrid X-pinches, the hot spot was <7 μm in size. There was a clear correlation between the soft and hard X-ray emission—pinches that produced intense soft X-ray emission from a small hot spot also produced the most intense, localized hard X-ray emission.

  • Journal article
    Wood JC, Chapman DJ, Poder K, Lopes NC, Rutherford ME, White TG, Albert F, Behm KT, Booth N, Bryant JSJ, Foster PS, Glenzer S, Hill E, Krushelnick K, Najmudin Z, Pollock BB, Rose S, Schumaker W, Scott RHH, Sherlock M, Thomas AGR, Zhao Z, Eakins D, Mangles SPDet al., 2018,

    Ultrafast imaging of laser driven shock waves using Betatron x-rays from a laser Wakefield accelerator

    , Scientific Reports, Vol: 8, ISSN: 2045-2322

    Betatron radiation from laser wakefield accelerators is an ultrashort pulsedsource of hard, synchrotron-like x-ray radiation. It emanates from a centimetrescale plasma accelerator producing GeV level electron beams. In recent yearsbetatron radiation has been developed as a unique source capable of producinghigh resolution x-ray images in compact geometries. However, until now, theshort pulse nature of this radiation has not been exploited. This reportdetails the first experiment to utilise betatron radiation to image a rapidlyevolving phenomenon by using it to radiograph a laser driven shock wave in asilicon target. The spatial resolution of the image is comparable to what hasbeen achieved in similar experiments at conventional synchrotron light sources.The intrinsic temporal resolution of betatron radiation is below 100 fs,indicating that significantly faster processes could be probed in futurewithout compromising spatial resolution. Quantitative measurements of the shockvelocity and material density were made from the radiographs recorded duringshock compression and were consistent with the established shock response ofsilicon, as determined with traditional velocimetry approaches. This suggeststhat future compact betatron imaging beamlines could be useful in the imagingand diagnosis of high-energy-density physics experiments.

  • Conference paper
    Sory DR, Amin HD, Rankin SM, Proud WGet al., 2018,

    Osteogenic Differentiation of Periosteum-Derived Stromal Cells in Blast-Associated Traumatic Loading

    , 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
  • Conference paper
    Tear GR, Chapman DJ, Proud WG, Ottley PR, Cullis IG, Gould PJ, Jones AWet al., 2018,

    The use of PDV to understand damage in rocket motor propellants

    , 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AIP Publishing, ISSN: 1551-7616

    Photonic Doppler Velocimetry (PDV) has been fielded on small scale fragment impact experiments on double base propellant. A 130 mm block of propellant was impacted with a 20 mm diameter cylinder at 1003 ± 10 m s-1 and four PDV probes recorded rear surface motion at different radial distances between 10 mm and 60 mm from impact centre. The PDV was fielded alongside high speed video diagnostics using a dichroic mirror which reflected visible light whilst transmitting the 1550 nm wavelength which the PDV operated at. The rear surface velocity was compared to 2D numerical simulations of the experiment and found to be in good agreement. Additional material moving at up to 2 km s-1 was detected at break out.

  • Conference paper
    Nguyen T-TN, Tear GR, Masouros SD, Proud WGet al., 2018,

    Fragment Penetrating Injury to Long Bones

    , 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
  • Conference paper
    Smith LC, Chapman DJ, Hooper PA, Whiteman G, Eakins DEet al., 2018,

    On the Dynamic Response of Additively Manufactured 316L

    , 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
  • Conference paper
    Brown KA, Butler BJ, Sory D, Nguyen T-TN, Williams A, Proud WGet al., 2018,

    Challenges in the Characterization of Failure and Resilience of Biological Materials

    , 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
  • Conference paper
    Ota TA, Chapman DJ, Richley JC, Eakins DEet al., 2018,

    Initial Results From a Simultaneous Pyrometry and Reflectivity Diagnostic

    , 20th Biennial Conference of the Topical-Group of the American-Physical-Society (APS) on Shock Compression of Condensed Matter (SCCM), Publisher: AMER INST PHYSICS, ISSN: 0094-243X
  • Journal article
    de Grouchy PWL, Kusse BR, Banasek J, Engelbrecht J, Hammer DA, Qi N, Rocco S, Bland SNet al., 2018,

    Observations of the magneto-Rayleigh-Taylor instability and shock dynamics in gas-puff Z-pinch experiments

    , PHYSICS OF PLASMAS, Vol: 25, ISSN: 1070-664X
  • Conference paper
    Tear G, Cohen A, Magnus D, Sory D, Proud Wet al., 2018,

    Damage characterisation for cement and concrete using microwave induced damage

    , International Conference on Experimental Mechanics, Publisher: MDPI, ISSN: 2504-3900

    Damage leading to failure in concrete and related materials is a complex behavior. Whilst many numerical approaches are available for simulating the degradation of material strength, it is difficult to discriminate between these models experimentally in the high strain rate ballistic impact regime. An experimental method has been developed to determine when local material failure has occurred, and whether the failure can be classed as fracture or granular flow. This method is tested on Kolsky bar and ballistic impact experiments. Comparison with numerical simulations is presented.

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