Search or filter publications

Filter by type:

Filter by publication type

Filter by year:

to

Results

  • Showing results for:
  • Reset all filters

Search results

  • Journal article
    Gurrutxaga-Lerma B, Balint D, Dini D, Eakins D, Sutton A, Gurrutxaga-Lerma B, Balint DS, Dini D, Eakins DE, Sutton APet al., 2013,

    A dynamic discrete dislocation plasticity method for the simulation of plastic relaxation under shock loading

    , Proceedings of the Royal Society A: Mathematical, Physical & Engineering Sciences, Vol: 469, ISSN: 1364-5021

    In this article, it is demonstrated that current methods of modelling plasticity as the collective motion of discrete dislocations, such as two-dimensional discrete dislocation plasticity (DDP), are unsuitable for the simulation of very high strain rate processes (106 s−1 or more) such as plastic relaxation during shock loading. Current DDP models treat dislocations quasi-statically, ignoring the time-dependent nature of the elastic fields of dislocations. It is shown that this assumption introduces unphysical artefacts into the system when simulating plasticity resulting from shock loading. This deficiency can be overcome only by formulating a fully time-dependent elastodynamic description of the elastic fields of discrete dislocations. Building on the work of Markenscoff & Clifton, the fundamental time-dependent solutions for the injection and non-uniform motion of straight edge dislocations are presented. The numerical implementation of these solutions for a single moving dislocation and for two annihilating dislocations in an infinite plane are presented. The application of these solutions in a two-dimensional model of time-dependent plasticity during shock loading is outlined here and will be presented in detail elsewhere.

  • Journal article
    Swadling GF, Lebedev SV, Hall GN, Suzuki-Vidal F, Burdiak G, Harvey-Thompson AJ, Bland SN, De Grouchy P, Khoory E, Pickworth L, Skidmore J, Suttle Let al., 2013,

    Shock-less interactions of ablation streams in tungsten wire array z-pinches

    , PHYSICS OF PLASMAS, Vol: 20, ISSN: 1070-664X
  • Journal article
    Burdiak GC, Lebedev SV, Hall GN, Harvey-Thompson AJ, Suzuki Vidal F, Swadling GF, Khoory E, Pickworth L, Bland SN, de Grouchy P, Skidmore Jet al., 2013,

    Determination of the inductance of imploding wire array Z-pinches using measurements of load voltage

    , Physics of Plasmas, Vol: 20, ISSN: 1089-7674

    The inductance of imploding cylindrical wire array z-pinches has been determined frommeasurements of load voltage and current. A thorough analysis method is presented that explainshow the load voltage of interest is found from raw signals obtained using a resistive voltagedivider. This method is applied to voltage data obtained during z-pinch experiments carried out onthe MAGPIE facility (1.4 MA, 240 ns rise-time) in order to calculate the load inductance andthereafter the radial trajectory of the effective current sheath during the snowplough implosion.Voltage and current are monitored very close to the load, allowing these calculations to be carriedout without the need for circuit modelling. Measurements give a convergence ratio for the currentof between 3.1 and 5.7 at stagnation of the pinch.

  • Journal article
    Sherlock M, Hill EG, Rose SJ, 2013,

    Kinetic simulations of the heating of solid density plasma by femtosecond laser pulses

    , HIGH ENERGY DENSITY PHYSICS, Vol: 9, Pages: 38-41, ISSN: 1574-1818
  • Journal article
    Burdiak GC, Lebedev SV, Drake RP, Harvey-Thompson AJ, Swadling GF, Suzuki-Vidal F, Skidmore J, Suttle L, Khoory E, Pickworth L, de Grouchy P, Hall GN, Bland SN, Weinwurm M, Chittenden JPet al., 2013,

    The production and evolution of multiple converging radiative shock waves in gas-filled cylindrical liner z-pinch experiments

    , HIGH ENERGY DENSITY PHYSICS, Vol: 9, Pages: 52-62, ISSN: 1574-1818
  • Journal article
    Suzuki-Vidal F, Lebedev SV, Krishnan M, Skidmore J, Swadling GF, Bocchi M, Harvey-Thompson AJ, Patankar S, Burdiak GC, de Grouchy P, Pickworth L, Stafford SJP, Suttle L, Bennett M, Bland SN, Chittenden JP, Hall GN, Khoory E, Smith RA, Ciardi A, Frank A, Madden RE, Wilson-Elliot K, Coleman Pet al., 2013,

    Interaction of radiatively cooled plasma jets with neutral gases for laboratory astrophysics studies

    , HIGH ENERGY DENSITY PHYSICS, Vol: 9, Pages: 141-147, ISSN: 1574-1818
  • Journal article
    Hall GN, Lebedev SV, Suzuki Vidal F, Swadling G, Chittenden JP, Bland SN, Harvey Thompson A, Knapp PF, Blesener IC, McBride RD, Chalenski DA, Blesener KS, Greenly JB, Pikuz SA, Shelkovenko TA, Hammer DA, Kusse BRet al., 2013,

    Ablation dynamics in coiled wire-array Z-pinches

    , Physics of Plasmas, Vol: 20, ISSN: 1089-7674

    Experiments to study the ablation dynamics of coiled wire arrays were performed on the MAGPIEgenerator (1 MA, 240 ns) at Imperial College, and on the COBRA generator at Cornell University’sLaboratory of Plasma Studies (1 MA, 100 ns). The MAGPIE generator was used to drive coiled wiresin an inverse array configuration to study the distribution of ablated plasma. Using interferometry tostudy the plasma distribution during the ablation phase, absolute quantitative measurements ofelectron line density demonstrated very high density contrasts between coiled ablation streams andinter-stream regions many millimetres from the wire. The measured density contrasts for a coiledarray were many times greater than that observed for a conventional array with straight wires,indicating that a much greater axial modulation of the ablated plasma may be responsible for theunique implosion dynamics of coiled arrays. Experiments on the COBRA generator were used tostudy the complex redirection of plasma around a coiled wire that gives rise to the ablation structureexhibited by coiled arrays. Observations of this complex 3D plasma structure were used to validatethe current model of coiled array ablation dynamics [Hall et al., Phys. Rev. Lett. 100, 065003(2008)], demonstrating irrefutably that plasma flow from the wires behaves as predicted. Coiled wireswere observed to ablate and implode in the same manner on both machines, indicating that currentrise time should not be an issue for the scaling of coiled arrays to larger machines with fast currentrise times.

  • Journal article
    Swadling GF, Lebedev SV, Niasse N, Chittenden JP, Hall GN, Suzuki-Vidal F, Burdiak G, Harvey-Thompson AJ, Bland SN, De Grouchy P, Khoory E, Pickworth L, Skidmore J, Suttle Let al., 2013,

    Oblique shock structures formed during the ablation phase of aluminium wire array z-pinches

    , PHYSICS OF PLASMAS, Vol: 20, ISSN: 1070-6631
  • Conference paper
    Lebedev SV, Suzuki-Vidal F, Bocchi M, Swadling GF, Burdiak G, Bland SN, de Grouchy P, Harvey-Thompson AJ, Khoory E, Patankar S, Pickworth L, Skidmore J, Smith R, Chittenden JP, Krishnan M, Madden R, Wilson-Elliot K, Ciardi A, Frank Aet al., 2013,

    University of Rochester, Rochester, NY, USA EXPERIMENTAL STUDIES OF SUPERSONIC RADIATIVELY COOLED PLASMA JETS

    , ECLA: European Conference on Laboratory Astrophysics, Publisher: E D P SCIENCES, Pages: 133-+, ISSN: 1633-4760
  • Conference paper
    Suzuki-Vidal F, Bocchi M, Lebedev SV, Skidmore J, Swadling G, Burdiak G, Harvey-Thompson AJ, de Grouchy P, Bland SN, Hall GN, Khoory E, Pickworth L, Suttle L, Chittenden JP, Krishnan M, Wilson-Elliot K, Madden R, Ciardi A, Frank Aet al., 2013,

    JET-AMBIENT INTERACTION OF A SUPERSONIC, RADIATIVELY-COOLED JET IN LABORATORY EXPERIMENTS

    , ECLA: European Conference on Laboratory Astrophysics, Publisher: E D P SCIENCES, Pages: 127-+, ISSN: 1633-4760
  • Journal article
    White S, Nersisyan G, Kettle B, Dzelzainis TWJ, McKeever K, Lewis CLS, Otten A, Siegenthaler K, Kraus D, Roth M, otherset al., 2013,

    X-ray scattering from warm dense iron

    , High Energy Density Physics, Vol: 9, Pages: 573-577
  • Journal article
    Winter RE, Cotton M, Harris EJ, Chapman DJ, Eakins D, McShane Get al., 2012,

    Plate-impact loading of cellular structures formed by selective laser melting

    , WIT Transactions on the Built Environment, Vol: 126, Pages: 145-156, ISSN: 1743-3509

    Studies of the shock loading of porous material have the potential to improve our understanding of factors such as density, crush strength and pore size on energy absorbing capability. Porous components were manufactured using Selective Laser Melting (SLM) in which layers of metal powder are fused together to create a structure specified by an electronic file. Samples have been manufactured in which a lattice is formed by an array of intersecting rods angled at 45 degrees to the surface of a 6 mm thick x ~100 mm diameter disc. The cell size is 1 mm3 and the density is 44.6% of solid. A 100 mm gas gun has been used to impact the porous samples onto solid stainless steel plates. Het-V laser interferometry was used to measure the velocity vs. time profile of the transmitted shock. The experimental results were compared with three dimensional computer predictions. It was found that the simulations reproduced the main features of the experimental record but tended to underestimate the measured velocities, suggesting that the codes were not calculating the energy absorbed by the lattice correctly. Additional calculations were performed with the aim of building a picture of the processes of energy absorption in cellular materials whose structure is varied systematically. These supporting studies suggest a possible explanation for the observed computational/experimental discrepancies. © 2012 British Crown.

  • Journal article
    Hill EG, Rose SJ, 2012,

    Modelling of Silicon in inertial confinement fusion conditions

    , HIGH ENERGY DENSITY PHYSICS, Vol: 8, Pages: 307-312, ISSN: 1574-1818
  • Journal article
    Ampleford DJ, Jennings CA, Lebedev SV, Bland SN, Cuneo ME, Sinars DB, Bott SC, Hall GN, Suzuki-Vidal F, Palmer JBA, Chittenden JPet al., 2012,

    Shock model description of the interaction radiation pulse in nested wire array z-pinches

    , PHYSICS OF PLASMAS, Vol: 19, ISSN: 1070-664X
  • Journal article
    Ampleford DJ, Bland SN, Cuneo ME, Lebedev SV, Sinars DB, Jennings CA, Waisman EM, Vesey RA, Hall GN, Suzuki-Vidal F, Chittenden JP, Bott SCet al., 2012,

    Demonstration of Radiation Pulse-Shaping Capabilities Using Nested Conical Wire-Array Z-Pinches

    , IEEE TRANSACTIONS ON PLASMA SCIENCE, Vol: 40, Pages: 3334-3346, ISSN: 0093-3813
  • Journal article
    Wilson LA, Tallents GJ, Pasley J, Whittaker DS, Rose SJ, Guilbaud O, Cassou K, Kazamias S, Daboussi S, Pittman M, Delmas O, Demailly J, Neveu O, Ros Det al., 2012,

    Energy transport in short-pulse-laser-heated targets measured using extreme ultraviolet laser backlighting

    , PHYSICAL REVIEW E, Vol: 86, ISSN: 1539-3755
  • Journal article
    Hill EG, Rose SJ, 2012,

    Thomson scattering in short pulse laser experiments

    , PHYSICS OF PLASMAS, Vol: 19, ISSN: 1070-664X
  • Journal article
    Scott RHH, Beaucourt C, Schlenvoigt H-P, Markey K, Lancaster KL, Ridgers CP, Brenner CM, Pasley J, Gray RJ, Musgrave IO, Robinson APL, Li K, Notley MM, Davies JR, Baton SD, Santos JJ, Feugeas J-L, Nicolai P, Malka G, Tikhonchuk VT, McKenna P, Neely D, Rose SJ, Norreys PAet al., 2012,

    Controlling Fast-Electron-Beam Divergence Using Two Laser Pulses

    , PHYSICAL REVIEW LETTERS, Vol: 109, ISSN: 0031-9007
  • Journal article
    Crowley BJB, Bingham R, Evans RG, Gericke DO, Landen OL, Murphy CD, Norreys PA, Rose SJ, Tschentscher T, Wang CH-T, Wark JS, Gregori Get al., 2012,

    Testing quantum mechanics in non-Minkowski space-time with high power lasers and 4th generation light sources

    , SCIENTIFIC REPORTS, Vol: 2, ISSN: 2045-2322
  • Journal article
    Suzuki-Vidal F, Lebedev SV, Bocchi M, Krishnan M, Swadling G, Burdiak G, Bland SN, de Grouchy P, Hall GN, Harvey-Thompson AJ, Khoory E, Pickworth L, Skidmore J, Chittenden JP, Wilson-Elliot K, Madden R, Ciardi Aet al., 2012,

    Experimental study of shock waves from the interaction of a supersonic plasma jet with an ambient gas

    , SHOCK WAVES, Vol: 22, Pages: 249-251, ISSN: 0938-1287
  • Journal article
    Scott RHH, Perez F, Santos JJ, Ridgers CP, Davies JR, Lancaster KL, Baton SD, Nicolai P, Trines RMGM, Bell AR, Hulin S, Tzoufras M, Rose SJ, Norreys PAet al., 2012,

    A study of fast electron energy transport in relativistically intense laser-plasma interactions with large density scalelengths

    , PHYSICS OF PLASMAS, Vol: 19, ISSN: 1070-664X
  • Journal article
    Harvey-Thompson AJ, Lebedev SV, Patankar S, Bland SN, Burdiak G, Chittenden JP, Colaitis A, De Grouchy P, Doyle HW, Hall GN, Khoory E, Hohenberger M, Pickworth L, Suzuki-Vidal F, Smith RA, Skidmore J, Suttle L, Swadling GFet al., 2012,

    Optical Thomson Scattering Measurements of Plasma Parameters in the Ablation Stage of Wire Array Z Pinches

    , Physical Review Letters, Vol: 108, Pages: 145002-1-145002-5
  • Conference paper
    Chapman D, Eakins D, Williamson D, Proud Wet al., 2012,

    Index of refraction measurements and window corrections for PMMA under shock compression

    , Conference of the American Physical Society Topical Group on Shock Compression of Condensed Matter, Publisher: American Institute of Physics, Pages: 442-445

    Symmetric plate impact experiments were performed to investigate the change in the refractive index of Polymethylmethacrylate (PMMA) under shock loading. Flyer and target geometries allowed the measurement of shock velocity, particle velocity, and refractive index in the shocked state, using a Het-V system (1550 nm). The change in refractive index of PMMA as a function of density is generally considered to be well described by the Gladstone-Dale relationship, meaning that the "apparent" velocity measured by a laser velocity interferometer is the "true" velocity, and hence there is no window correction. The results presented here demonstrate that the behaviour of PMMA deviates from an ideal Gladstone-Dale description, requiring a small velocity correction of order 1% at peak stresses up to 1.9 GPa. These results are consistent with literature values measured using a wavelength of 632.8 nm by [1].

  • Conference paper
    Eakins D, Chapman D, 2012,

    The influence of particle morphology on the dynamic densification of metal powders

    , Shock Compression of Condensed Matter, Pages: 1491-1494

    Powders are well known for their dispersive properties, which derive from the many dissipative processes that occur during densification. While numerous studies have been devoted to understand these processes over a wide range of initial densities, the influence of particle morphology has been for the large part overlooked. In this paper, we discuss a new research campaign at the Institute of Shock Physics, to systematically investigate the role of starting configuration on the dynamic densification of metal powders. Multi-target gun loading experiments have been performed on both stainless steel and copper powders of equiaxed- and fiber-shaped morphology. Frequency-shifted PDV was employed to measure the structure and velocity of the dynamic densification wave, to yield the crush strength of the various powders. We find that while the crush strength for the stainless steel powders is reasonably described by a modified Wu-Jing model, this model underpredicts the densification stress for the copper powder.

  • Conference paper
    Collinson M, Chapman D, Burchell M, Williamson D, Eakins Det al., 2012,

    Towards the role of interfacial shear in shock-induced intermetallic reactions

    , Shock Compression of Condensed Matter, Publisher: American Institute of Physics (AIP), Pages: 327-330, ISSN: 1551-7616

    Shock-induced intermetallic reactions have previously been shown to occur on a nanosecond timescale, with the role of mass mixing processes driven by inter-facial shear at material interfaces suggested as a possible explanation. Experimental setups allowing the role of friction on these mechanisms to be considered are presented. Simulations show that the use of an impedance mismatch, shock driven experimental setup should allow sliding velocities of 50 - 100 m s⁻¹ to be attained with mechanical mixing the main reaction mechanism. A second setup utilising the oblique impact of small spherical projectiles upon a target plate is predicted to enable much higher sliding velocities of up to 2 Km s⁻¹ to be attained with thermally driven diffusion reaction mechanisms becoming dominant.

  • Conference paper
    Jones D, Eakins DE, Hazell P, Chapman D, Appleby-Thomas Get al., 2012,

    Development of the gas gun driven expanding cylinder technique

    , Conference of the American Physical Society Topical Group on Shock Compression of Condensed Matter, Publisher: American Institute of Physics (AIP), Pages: 1141-1144, ISSN: 1551-7616

    Using a gas gun to create rapid expansion in metal cylinders to investigate fracture and fragmentaion has been commonplace for the last several decades. Results from such experiments alongside data from explosive and electromagnetic expansion techniques have produced several models for fragment size and mass distributions. We present a new geometry for expansion that can be applied to cylinders at elevated & reduced temperatures whilst keeping the drive mechanism constant, enabling us in the future to experiment over a range of sample temperatures at a fixed strain rate and loading path. This new geometry has been investigated through a series of gas gun experiments employing X-ray radiography and AUTODYN simulations to reveal the deformation and failure behaviour within the cylinder.

  • Journal article
    Harvey-Thompson AJ, Lebedev SV, Patankar S, Bland SN, Burdiak G, Chittenden JP, Colaitis A, De Grouchy P, Hall GN, Khoory E, Hohenberger M, Pickworth L, Suzuki-Vidal F, Smith RA, Skidmore J, Suttle L, Swadling GFet al., 2012,

    Optical Thomson scattering measurements of cylindrical wire array parameters

    , Physics of Plasmas, Vol: 19, Pages: 056303-1-056303-10, ISSN: 1070-664X
  • Journal article
    Eakins D, Chapman D,

    The influence of particle morphology on the dynamic densification of metal powders

    , AIP Conference Proceedings, Vol: 1426, Pages: 1491-1494, ISSN: 1551-7616

    Powders are well known for their dispersive properties, which derive from the many dissipative processes that occur during densification. While numerous studies have been devoted to understand these processes over a wide range of initial densities, the influence of particle morphology has been for the large part overlooked. In this paper, we discuss a new research campaign at the Institute of Shock Physics, to systematically investigate the role of starting configuration on the dynamic densification of metal powders. Multi-target gun loading experiments have been performed on both stainless steel and copper powders of equiaxed-and fiber-shaped morphology. Frequency-shifted PDV was employed to measure the structure and velocity of the dynamic densification wave, to yield the crush strength of the various powders. We find that while the crush strength for the stainless steel powders is reasonably described by a modifiedWu-Jing model, this model underpredicts the densification stress for the copper powder.

  • Journal article
    Neal WD, Chapman DJ, Proud WG, 2012,

    Shock-wave stability in quasi-mono-disperse granular materials

    , EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS, Vol: 57, ISSN: 1286-0042
  • Journal article
    Suzuki-Vidal F, Bocchi M, Lebedev SV, Swadling GF, Burdiak G, Bland SN, de Grouchy P, Hall GN, Harvey-Thompson AJ, Khoory E, Patankar S, Pickworth L, Skidmore J, Smith R, Chittenden JP, Krishnan M, Madden RE, Wilson-Elliot K, Ciardi A, Frank Aet al., 2012,

    Interaction of a supersonic, radiatively cooled plasma jet with an ambient medium

    , PHYSICS OF PLASMAS, Vol: 19, ISSN: 1070-664X

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://wlsprd.imperial.ac.uk:80/respub/WEB-INF/jsp/search-t4-html.jsp Request URI: /respub/WEB-INF/jsp/search-t4-html.jsp Query String: id=280&limit=30&page=2&respub-action=search.html Current Millis: 1606397662533 Current Time: Thu Nov 26 13:34:22 GMT 2020