1
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Lev B, Chennath M, Cranfield CG, Cornelius F, Allen TW, Clarke RJ. Involvement of the alpha-subunit N-terminus in the mechanism of the Na +,K +-ATPase. Biochim Biophys Acta Mol Cell Res 2023; 1870:119539. [PMID: 37479188 DOI: 10.1016/j.bbamcr.2023.119539] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/26/2023] [Accepted: 07/10/2023] [Indexed: 07/23/2023]
Abstract
Previous studies have shown that cytoplasmic K+ release and the associated E2 → E1 conformational change of the Na+,K+-ATPase is a major rate-determining step of the enzyme's ion pumping cycle and hence a prime site of acute regulatory intervention. From the ionic strength dependence of the enzyme's distribution between the E2 and E1 states, it has also been found that E2 is stabilized by an electrostatic attraction. Any disruption of this electrostatic attraction would, thus, have profound effects on the rate of ion pumping. The aim of this paper is to identify the location of this interaction. Using enhanced-sampling molecular dynamics simulations with a predicted N-terminal structure added to the X-ray crystal structure of the Na+,K+-ATPase, a previously postulated salt bridge between Lys32 and Glu233 (rat sequence numbering) of the enzyme's α-subunit can be excluded. The residues never approach closely enough to form a salt bridge. In contrast, strong interactions with anionic lipid head groups were seen. To investigate the possibility of a protein-lipid interaction experimentally, the surface charge density of Na+,K+-ATPase-containing membrane fragments was estimated from zeta potential measurements to be 0.019 (± 0.001) C m-2. This is in good agreement with the charge density previously determined to be responsible for stabilization of the E2 state of 0.023 (± 0.009) C m-2 and the membrane charge density estimated here from published electron-microscopic images of 0.018C m-2. The results are, therefore, consistent with an interaction of the Na+,K+-ATPase α-subunit N-terminus with negatively-charged lipid head groups of the neighbouring cytoplasmic membrane surface as the origin of the electrostatic interaction stabilising the E2 state.
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Affiliation(s)
- B Lev
- School of Science, RMIT University, Melbourne, Vic, 3001, Australia
| | - M Chennath
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - C G Cranfield
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - F Cornelius
- Department of Biomedicine, University of Aarhus, DK-8000 Aarhus, C, Denmark
| | - T W Allen
- School of Science, RMIT University, Melbourne, Vic, 3001, Australia
| | - R J Clarke
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia; The University of Sydney Nano Institute, Sydney, NSW 2006, Australia.
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2
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Paddock RW, von der Leyen MW, Aboushelbaya R, Norreys PA, Chapman DJ, Eakins DE, Oliver M, Clarke RJ, Notley M, Baird CD, Booth N, Spindloe C, Haddock D, Irving S, Scott RHH, Pasley J, Cipriani M, Consoli F, Albertazzi B, Koenig M, Martynenko AS, Wegert L, Neumayer P, Tchórz P, Rączka P, Mabey P, Garbett W, Goshadze RMN, Karasiev VV, Hu SX. Measuring the principal Hugoniot of inertial-confinement-fusion-relevant TMPTA plastic foams. Phys Rev E 2023; 107:025206. [PMID: 36932569 DOI: 10.1103/physreve.107.025206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 12/09/2022] [Indexed: 06/18/2023]
Abstract
Wetted-foam layers are of significant interest for inertial-confinement-fusion capsules, due to the control they provide over the convergence ratio of the implosion and the opportunity this affords to minimize hydrodynamic instability growth. However, the equation of state for fusion-relevant foams are not well characterized, and many simulations rely on modeling such foams as a homogeneous medium with the foam average density. To address this issue, an experiment was performed using the VULCAN Nd:glass laser at the Central Laser Facility. The aim was to measure the principal Hugoniot of TMPTA plastic foams at 260mg/cm^{3}, corresponding to the density of liquid DT-wetted-foam layers, and their "hydrodynamic equivalent" capsules. A VISAR was used to obtain the shock velocity of both the foam and an α-quartz reference layer, while streaked optical pyrometry provided the temperature of the shocked material. The measurements confirm that, for the 20-120 GPa pressure range accessed, this material can indeed be well described using the equation of state of the homogeneous medium at the foam density.
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Affiliation(s)
- R W Paddock
- Department of Physics, Atomic and Laser Physics Sub-Department, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | - M W von der Leyen
- Department of Physics, Atomic and Laser Physics Sub-Department, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | - R Aboushelbaya
- Department of Physics, Atomic and Laser Physics Sub-Department, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | - P A Norreys
- Department of Physics, Atomic and Laser Physics Sub-Department, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | - D J Chapman
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - D E Eakins
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - M Oliver
- Central Laser Facility, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - R J Clarke
- Central Laser Facility, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - M Notley
- Central Laser Facility, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - C D Baird
- Central Laser Facility, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - N Booth
- Central Laser Facility, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - C Spindloe
- Central Laser Facility, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - D Haddock
- Central Laser Facility, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - S Irving
- Central Laser Facility, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - R H H Scott
- Central Laser Facility, STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom
| | - J Pasley
- York Plasma Institute, School of Physics, Electronics and Technology, University of York, York YO10 5DD, United Kingdom
| | - M Cipriani
- ENEA, Fusion and Technology for Nuclear Safety and Security Department, C.R.Frascati, via E. Fermi 45, 00044 Frascati, Rome, Italy
| | - F Consoli
- ENEA, Fusion and Technology for Nuclear Safety and Security Department, C.R.Frascati, via E. Fermi 45, 00044 Frascati, Rome, Italy
| | - B Albertazzi
- LULI - CNRS, CEA, Sorbonne Universités, Ecole Polytechnique, Institut Polytechnique de Paris-F-91120 Palaiseau cedex, France
| | - M Koenig
- LULI - CNRS, CEA, Sorbonne Universités, Ecole Polytechnique, Institut Polytechnique de Paris-F-91120 Palaiseau cedex, France
| | - A S Martynenko
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany
| | - L Wegert
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany
| | - P Neumayer
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany
| | - P Tchórz
- Institute of Plasma Physics and Laser Microfusion, 01-497 Warsaw, Poland
| | - P Rączka
- Institute of Plasma Physics and Laser Microfusion, 01-497 Warsaw, Poland
| | - P Mabey
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - W Garbett
- AWE plc, Aldermaston, Reading, Berkshire RG7 4PR, United Kingdom
| | - R M N Goshadze
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - V V Karasiev
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - S X Hu
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
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3
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Wilson R, King M, Butler NMH, Carroll DC, Frazer TP, Duff MJ, Higginson A, Dance RJ, Jarrett J, Davidson ZE, Armstrong CD, Liu H, Hawkes SJ, Clarke RJ, Neely D, Gray RJ, McKenna P. Influence of spatial-intensity contrast in ultraintense laser-plasma interactions. Sci Rep 2022; 12:1910. [PMID: 35115579 PMCID: PMC8814164 DOI: 10.1038/s41598-022-05655-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 01/05/2022] [Indexed: 11/09/2022] Open
Abstract
Increasing the intensity to which high power laser pulses are focused has opened up new research possibilities, including promising new approaches to particle acceleration and phenomena such as high field quantum electrodynamics. Whilst the intensity achievable with a laser pulse of a given power can be increased via tighter focusing, the focal spot profile also plays an important role in the interaction physics. Here we show that the spatial-intensity distribution, and specifically the ratio of the intensity in the peak of the laser focal spot to the halo surrounding it, is important in the interaction of ultraintense laser pulses with solid targets. By comparing proton acceleration measurements from foil targets irradiated with by a near-diffraction-limited wavelength scale focal spot and larger F-number focusing, we find that this spatial-intensity contrast parameter strongly influences laser energy coupling to fast electrons. We find that for multi-petawatt pulses, spatial-intensity contrast is potentially as important as temporal-intensity contrast.
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Affiliation(s)
- R Wilson
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK
| | - M King
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK.,The Cockcroft Institute, Sci-Tech Daresbury, Warrington, WA4 4AD, UK
| | - N M H Butler
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK
| | - D C Carroll
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, UK
| | - T P Frazer
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK
| | - M J Duff
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK
| | - A Higginson
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK
| | - R J Dance
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK
| | - J Jarrett
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK
| | - Z E Davidson
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK
| | - C D Armstrong
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK.,Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, UK
| | - H Liu
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, UK.,Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - S J Hawkes
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, UK
| | - R J Clarke
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, UK
| | - D Neely
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK.,Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, UK
| | - R J Gray
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK
| | - P McKenna
- SUPA Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK. .,The Cockcroft Institute, Sci-Tech Daresbury, Warrington, WA4 4AD, UK.
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Jayathungage Don TD, Suresh V, Cater JE, Clarke RJ. Modelling uptake and transport of therapeutic agents through the lymphatic system. Comput Methods Biomech Biomed Engin 2021; 25:861-874. [PMID: 34592851 DOI: 10.1080/10255842.2021.1984434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The ability of the lymphatic network to absorb large molecules and bypass the first-pass liver metabolism makes it appealing as a delivery system for therapeutic substances. In most cases, the drug is injected into the subcutaneous tissue and must negotiate the tissue space, before being drained via the lymphatics. Tracking the transport of drug molecules through this route is challenging, and computational models of lymphatic drainage can play an important role in assessing the efficacy of a proposed delivery strategy. The three-dimensional computational model we present here of the peripheral lymphatic network and surrounding interstitium is informed by anatomical data, and quantifies the degree to which uptake and transit times are affected by drug particle size, physiological flow rates, and specifics of drug injection.
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Affiliation(s)
- T D Jayathungage Don
- Department of Engineering Science, University of Auckland, Auckland, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - V Suresh
- Department of Engineering Science, University of Auckland, Auckland, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - J E Cater
- Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - R J Clarke
- Department of Engineering Science, University of Auckland, Auckland, New Zealand
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5
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Hossain KR, Li X, Zhang T, Paula S, Cornelius F, Clarke RJ. Polarity of the ATP binding site of the Na +,K +-ATPase, gastric H +,K +-ATPase and sarcoplasmic reticulum Ca 2+-ATPase. Biochim Biophys Acta Biomembr 2019; 1862:183138. [PMID: 31790695 DOI: 10.1016/j.bbamem.2019.183138] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/15/2019] [Accepted: 11/27/2019] [Indexed: 11/18/2022]
Abstract
A fluorescence ratiometric method utilizing the probe eosin Y is presented for estimating the ATP binding site polarity of P-type ATPases in different conformational states. The method has been calibrated by measurements in a series of alcohols and tested using complexation of eosin Y with methyl-β-cyclodextrin. The results obtained with the Na+,K+-, H+,K+- and sarcoplasmic reticulum Ca2+-ATPases indicate that the ATP binding site, to which eosin is known to bind, is significantly more polar in the case of the Na+,K+- and H+,K+-ATPases compared to the Ca2+-ATPase. This result was found to be consistent with docking calculations of eosin with the E2 conformational state of the Na+,K+-ATPase and the Ca2+-ATPase. Fluorescence experiments showed that eosin binds significantly more strongly to the E1 conformation of the Na+,K+-ATPase than the E2 conformation, but in the case of the Ca2+-ATPase both fluorescence experiments and docking calculations showed no significant difference in binding affinity between the two conformations. This result could be due to the fact that, in contrast to the Na+,K+- and H+,K+-ATPases, the E2-E1 transition of the Ca2+-ATPase does not involve the movement of a lysine-rich N-terminal tail which may affect the overall enzyme conformation. Consistent with this hypothesis, the eosin affinity of the E1 conformation of the Na+,K+-ATPase was significantly reduced after N-terminal truncation. It is suggested that changes in conformational entropy of the N-terminal tail of the Na+, K+- and the H+,K+-ATPases during the E2-E1 transition could affect the thermodynamic stability of the E1 conformation and hence its ATP binding affinity.
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Affiliation(s)
- K R Hossain
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
| | - X Li
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
| | - T Zhang
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - S Paula
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - F Cornelius
- Department of Biomedicine, University of Aarhus, DK-8000 Aarhus C, Denmark
| | - R J Clarke
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia; The University of Sydney Nano Institute, Sydney, NSW 2006, Australia.
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6
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Romagnani L, Robinson APL, Clarke RJ, Doria D, Lancia L, Nazarov W, Notley MM, Pipahl A, Quinn K, Ramakrishna B, Wilson PA, Fuchs J, Willi O, Borghesi M. Dynamics of the Electromagnetic Fields Induced by Fast Electron Propagation in Near-Solid-Density Media. Phys Rev Lett 2019; 122:025001. [PMID: 30720299 DOI: 10.1103/physrevlett.122.025001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 10/01/2018] [Indexed: 06/09/2023]
Abstract
The propagation of fast electron currents in near solid-density media was investigated via proton probing. Fast currents were generated inside dielectric foams via irradiation with a short (∼0.6 ps) laser pulse focused at relativistic intensities (Iλ^{2}∼4×10^{19} W cm^{-2} μm^{2}). Proton probing provided a spatially and temporally resolved characterization of the evolution of the electromagnetic fields and of the associated net currents directly inside the target. The progressive growth of beam filamentation was temporally resolved and information on the divergence of the fast electron beam was obtained. Hybrid simulations of electron propagation in dense media indicate that resistive effects provide a major contribution to field generation and explain well the topology, magnitude, and temporal growth of the fields observed in the experiment. Estimations of the growth rates for different types of instabilities pinpoints the resistive instability as the most likely dominant mechanism of beam filamentation.
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Affiliation(s)
- L Romagnani
- LULI-CNRS, Ecole Polytechnique, CEA, Université Paris-Saclay, F-91128 Palaiseau cedex, France
- Centre for Plasma Physics, School of Mathematics and Physics, The Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
| | - A P L Robinson
- Central Laser Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, United Kingdom
| | - R J Clarke
- Central Laser Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, United Kingdom
| | - D Doria
- Centre for Plasma Physics, School of Mathematics and Physics, The Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
- Extreme Light Infrastructure-Nuclear Physics (ELI-NP), Horia Hulubei Institute for Nuclear Physics (IFIN-HH), Reactorului Str., 30, Magurele 077126, Bucharest, Romania
| | - L Lancia
- LULI-CNRS, Ecole Polytechnique, CEA, Université Paris-Saclay, F-91128 Palaiseau cedex, France
| | - W Nazarov
- School of Chemistry, University of St. Andrews, St Andrews KY16 9ST, United Kingdom
| | - M M Notley
- Central Laser Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, United Kingdom
| | - A Pipahl
- Institut für Laser-und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf, 40225, Germany
| | - K Quinn
- Centre for Plasma Physics, School of Mathematics and Physics, The Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
| | - B Ramakrishna
- Department of Physics, Indian Institute of Technology Hyderabad 502285, India
| | - P A Wilson
- School of Engineering, University of South Australia, Adelaide SA 5095, Australia
- Department of Medical Physics, Royal Adelaide Hospital, Adelaide SA 5000, Australia
| | - J Fuchs
- LULI-CNRS, Ecole Polytechnique, CEA, Université Paris-Saclay, F-91128 Palaiseau cedex, France
| | - O Willi
- Institut für Laser-und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf, 40225, Germany
| | - M Borghesi
- Centre for Plasma Physics, School of Mathematics and Physics, The Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
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7
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Pickering TR, Heaton JL, Clarke RJ, Stratford D. Hominin vertebrae and upper limb bone fossils from Sterkfontein Caves, South Africa (1998-2003 excavations). Am J Phys Anthropol 2018; 168:459-480. [DOI: 10.1002/ajpa.23758] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/08/2018] [Accepted: 11/05/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Travis Rayne Pickering
- Department of Anthropology; University of Wisconsin-Madison; Madison Wisconsin
- Evolutionary Studies Institute; University of the Witwatersand; Johannesburg South Africa
- Plio-Pleistocene Palaeontology Section, Department of Vertebrates; Ditsong National Museum of Natural History (Transvaal Museum); Pretoria South Africa
| | - Jason L. Heaton
- Evolutionary Studies Institute; University of the Witwatersand; Johannesburg South Africa
- Plio-Pleistocene Palaeontology Section, Department of Vertebrates; Ditsong National Museum of Natural History (Transvaal Museum); Pretoria South Africa
- Department of Biology; Birmingham-Southern College; Birmingham Alabama
| | - R. J. Clarke
- Evolutionary Studies Institute; University of the Witwatersand; Johannesburg South Africa
| | - Dominic Stratford
- School of Geography, Archaeology and Environmental Studies; University of the Witwatersrand; Johannesburg South Africa
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8
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Abstract
One challenge for hepatic flow simulation is to divide the hepatic vasculature into individual Couinaud segments, and to simulate flow at both segmental and organ levels. We propose to integrate a segment simulation algorithm with the flow solver in a Constructive Constraint Optimisation (CCO) algorithm to address this problem. In this way blood flow simulations can be conducted for large segment-specific vasculatures as relevant to surgical procedures. In this short communication we outline the methods and present some preliminary results.
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Affiliation(s)
- N Barléon
- a Department of Fluid Mechanics and Hydraulics , ENSEEIHT, National Polytechnic Institute of Toulouse , Toulouse , France
| | - R J Clarke
- b Department of Engineering Science , The University of Auckland , Auckland , New Zealand
| | - H Ho
- c Auckland Bioengineering Institute , The University of Auckland , Auckland , New Zealand
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9
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Holloway CR, Cupples G, Smith DJ, Green JEF, Clarke RJ, Dyson RJ. Influences of transversely isotropic rheology and translational diffusion on the stability of active suspensions. R Soc Open Sci 2018; 5:180456. [PMID: 30225034 PMCID: PMC6124136 DOI: 10.1098/rsos.180456] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/03/2018] [Indexed: 06/08/2023]
Abstract
Suspensions of self-motile, elongated particles are a topic of significant current interest, exemplifying a form of 'active matter'. Examples include self-propelling bacteria, algae and sperm, and artificial swimmers. Ericksen's model of a transversely isotropic fluid (Ericksen 1960 Colloid Polym. Sci.173, 117-122 (doi:10.1007/bf01502416)) treats suspensions of non-motile particles as a continuum with an evolving preferred direction; this model describes fibrous materials as diverse as extracellular matrix, textile tufts and plant cell walls. Director-dependent effects are incorporated through a modified stress tensor with four viscosity-like parameters. By making fundamental connections with recent models for active suspensions, we propose a modification to Ericksen's model, mainly the inclusion of self-motility; this can be considered the simplest description of an oriented suspension including transversely isotropic effects. Motivated by the fact that transversely isotropic fluids exhibit modified flow stability, we conduct a linear stability analysis of two distinct cases, aligned and isotropic suspensions of elongated active particles. Novel aspects include the anisotropic rheology and translational diffusion. In general, anisotropic effects increase the instability of small perturbations, while translational diffusion stabilizes a range of wave-directions and, in some cases, a finite range of wavenumbers, thus emphasizing that both anisotropy and translational diffusion can have important effects in these systems.
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Affiliation(s)
- C. R. Holloway
- School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK
| | - G. Cupples
- School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK
| | - D. J. Smith
- School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK
- Institute for Metabolism and Systems Research, University of Birmingham, Birmingham B15 2TT, UK
| | - J. E. F. Green
- School of Mathematical Sciences, University of Adelaide, Adelaide, Australia
| | - R. J. Clarke
- Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - R. J. Dyson
- School of Mathematics, University of Birmingham, Birmingham B15 2TT, UK
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10
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Rusby DR, Armstrong CD, Brenner CM, Clarke RJ, McKenna P, Neely D. Novel scintillator-based x-ray spectrometer for use on high repetition laser plasma interaction experiments. Rev Sci Instrum 2018; 89:073502. [PMID: 30068096 DOI: 10.1063/1.5019213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The characterisation of x-rays from laser-plasma interactions is of utmost importance as they can be useful for both monitoring electron dynamics and also applications in an industrial capacity. A novel versatile scintillator x-ray spectrometer diagnostic that is capable of single shot measurements of x-rays produced from laser-plasma interactions is presented here. Examples of the design and extraction of the temperature of the spectrum of x-rays produced in an intense laser-solid interaction (479 ± 39 keV) and the critical energy from a betatron source (30 ± 10 keV) are discussed. Finally, a simple optimisation process involving adjusting the scintillator thickness for a particular range of input spectra is demonstrated.
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Affiliation(s)
- D R Rusby
- STFC, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - C D Armstrong
- STFC, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - C M Brenner
- STFC, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - R J Clarke
- STFC, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - P McKenna
- SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - D Neely
- STFC, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
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11
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Scott GG, Carroll DC, Astbury S, Clarke RJ, Hernandez-Gomez C, King M, Alejo A, Arteaga IY, Dance RJ, Higginson A, Hook S, Liao G, Liu H, Mirfayzi SR, Rusby DR, Selwood MP, Spindloe C, Tolley MK, Wagner F, Zemaityte E, Borghesi M, Kar S, Li Y, Roth M, McKenna P, Neely D. Dual Ion Species Plasma Expansion from Isotopically Layered Cryogenic Targets. Phys Rev Lett 2018; 120:204801. [PMID: 29864368 DOI: 10.1103/physrevlett.120.204801] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 02/19/2018] [Indexed: 06/08/2023]
Abstract
A dual ion species plasma expansion scheme from a novel target structure is introduced, in which a nanometer-thick layer of pure deuterium exists as a buffer species at the target-vacuum interface of a hydrogen plasma. Modeling shows that by controlling the deuterium layer thickness, a composite H^{+}/D^{+} ion beam can be produced by target normal sheath acceleration (TNSA), with an adjustable ratio of ion densities, as high energy proton acceleration is suppressed by the acceleration of a spectrally peaked deuteron beam. Particle in cell modeling shows that a (4.3±0.7) MeV per nucleon deuteron beam is accelerated, in a directional cone of half angle 9°. Experimentally, this was investigated using state of the art cryogenic targetry and a spectrally peaked deuteron beam of (3.4±0.7) MeV per nucleon was measured in a cone of half angle 7°-9°, while maintaining a significant TNSA proton component.
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Affiliation(s)
- G G Scott
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - D C Carroll
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - S Astbury
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - R J Clarke
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - C Hernandez-Gomez
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - M King
- Department of Physics SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - A Alejo
- Department of Pure and Applied Physics, Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
| | - I Y Arteaga
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - R J Dance
- Department of Physics SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - A Higginson
- Department of Physics SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - S Hook
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - G Liao
- Key Laboratory for Laser Plasmas (MoE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - H Liu
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - S R Mirfayzi
- Department of Pure and Applied Physics, Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
| | - D R Rusby
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
- Department of Physics SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - M P Selwood
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - C Spindloe
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - M K Tolley
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - F Wagner
- PHELIX group, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt 64291, Germany
| | - E Zemaityte
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
- Department of Physics SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - M Borghesi
- Department of Pure and Applied Physics, Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
| | - S Kar
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
- Department of Pure and Applied Physics, Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
| | - Y Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - M Roth
- Fachbereich Physik, Technische Universität Darmstadt, Darmstadt 64289, Germany
| | - P McKenna
- Department of Physics SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - D Neely
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
- Department of Physics SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
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12
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Booth N, Robinson APL, Hakel P, Clarke RJ, Dance RJ, Doria D, Gizzi LA, Gregori G, Koester P, Labate L, Levato T, Li B, Makita M, Mancini RC, Pasley J, Rajeev PP, Riley D, Wagenaars E, Waugh JN, Woolsey NC. Laboratory measurements of resistivity in warm dense plasmas relevant to the microphysics of brown dwarfs. Nat Commun 2015; 6:8742. [PMID: 26541650 PMCID: PMC4667641 DOI: 10.1038/ncomms9742] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 09/28/2015] [Indexed: 11/09/2022] Open
Abstract
Since the observation of the first brown dwarf in 1995, numerous studies have led to a better understanding of the structures of these objects. Here we present a method for studying material resistivity in warm dense plasmas in the laboratory, which we relate to the microphysics of brown dwarfs through viscosity and electron collisions. Here we use X-ray polarimetry to determine the resistivity of a sulphur-doped plastic target heated to Brown Dwarf conditions by an ultra-intense laser. The resistivity is determined by matching the plasma physics model to the atomic physics calculations of the measured large, positive, polarization. The inferred resistivity is larger than predicted using standard resistivity models, suggesting that these commonly used models will not adequately describe the resistivity of warm dense plasma related to the viscosity of brown dwarfs.
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Affiliation(s)
- N Booth
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - A P L Robinson
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - P Hakel
- Department of Physics, College of Science, University of Nevada, Reno, Nevada 89557-0208, USA
| | - R J Clarke
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - R J Dance
- Department of Physics, York Plasma Institute, University of York, Heslington York YO10 5DD, UK
| | - D Doria
- School of Mathematics and Physics, Queen's University Belfast, Belfast BT1 4NN, UK
| | - L A Gizzi
- Intense Laser Irradiation Laboratory, Istituto Nazionale di Ottica, Area della Ricerca del CNR, 56124 Pisa, Italy
| | - G Gregori
- Department of Physics, University of Oxford, Oxford OX4 3PU, UK
| | - P Koester
- Intense Laser Irradiation Laboratory, Istituto Nazionale di Ottica, Area della Ricerca del CNR, 56124 Pisa, Italy
| | - L Labate
- Intense Laser Irradiation Laboratory, Istituto Nazionale di Ottica, Area della Ricerca del CNR, 56124 Pisa, Italy
| | - T Levato
- Intense Laser Irradiation Laboratory, Istituto Nazionale di Ottica, Area della Ricerca del CNR, 56124 Pisa, Italy
| | - B Li
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - M Makita
- School of Mathematics and Physics, Queen's University Belfast, Belfast BT1 4NN, UK
| | - R C Mancini
- Department of Physics, College of Science, University of Nevada, Reno, Nevada 89557-0208, USA
| | - J Pasley
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.,Department of Physics, York Plasma Institute, University of York, Heslington York YO10 5DD, UK
| | - P P Rajeev
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - D Riley
- School of Mathematics and Physics, Queen's University Belfast, Belfast BT1 4NN, UK
| | - E Wagenaars
- Department of Physics, York Plasma Institute, University of York, Heslington York YO10 5DD, UK
| | - J N Waugh
- Department of Physics, York Plasma Institute, University of York, Heslington York YO10 5DD, UK
| | - N C Woolsey
- Department of Physics, York Plasma Institute, University of York, Heslington York YO10 5DD, UK
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13
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Sumets PP, Cater JE, Long DS, Clarke RJ. A boundary-integral representation for biphasic mixture theory, with application to the post-capillary glycocalyx. Proc Math Phys Eng Sci 2015; 471:20140955. [PMID: 26345494 PMCID: PMC4528650 DOI: 10.1098/rspa.2014.0955] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 05/11/2015] [Indexed: 12/04/2022] Open
Abstract
We describe a new boundary-integral representation for biphasic mixture theory, which allows us to efficiently solve certain elastohydrodynamic–mobility problems using boundary element methods. We apply this formulation to model the motion of a rigid particle through a microtube which has non-uniform wall shape, is filled with a viscous Newtonian fluid, and is lined with a thin poroelastic layer. This is relevant to scenarios such as the transport of small rigid cells (such as neutrophils) through microvessels that are lined with an endothelial glycocalyx layer (EGL). In this context, we examine the impact of geometry upon some recently reported phenomena, including the creation of viscous eddies, fluid flux into the EGL, as well as the role of the EGL in transmitting mechanical signals to the underlying endothelial cells.
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Affiliation(s)
- P P Sumets
- Department of Engineering Science , University of Auckland , Auckland 1142, New Zealand
| | - J E Cater
- Department of Engineering Science , University of Auckland , Auckland 1142, New Zealand
| | - D S Long
- Department of Engineering Science , University of Auckland , Auckland 1142, New Zealand ; Auckland Bioengineering Institute , University of Auckland , Auckland 1142, New Zealand
| | - R J Clarke
- Department of Engineering Science , University of Auckland , Auckland 1142, New Zealand
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14
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Deas RM, Wilson LA, Rusby D, Alejo A, Allott R, Black PP, Black SE, Borghesi M, Brenner CM, Bryant J, Clarke RJ, Collier JC, Edwards B, Foster P, Greenhalgh J, Hernandez-Gomez C, Kar S, Lockley D, Moss RM, Najmudin Z, Pattathil R, Symes D, Whittle MD, Wood JC, McKenna P, Neely D. A laser driven pulsed X-ray backscatter technique for enhanced penetrative imaging. J Xray Sci Technol 2015; 23:791-797. [PMID: 26756414 DOI: 10.3233/xst-150520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
X-ray backscatter imaging can be used for a wide range of imaging applications, in particular for industrial inspection and portal security. Currently, the application of this imaging technique to the detection of landmines is limited due to the surrounding sand or soil strongly attenuating the 10s to 100s of keV X-rays required for backscatter imaging. Here, we introduce a new approach involving a 140 MeV short-pulse (< 100 fs) electron beam generated by laser wakefield acceleration to probe the sample, which produces Bremsstrahlung X-rays within the sample enabling greater depths to be imaged. A variety of detector and scintillator configurations are examined, with the best time response seen from an absorptive coated BaF2 scintillator with a bandpass filter to remove the slow scintillation emission components. An X-ray backscatter image of an array of different density and atomic number items is demonstrated. The use of a compact laser wakefield accelerator to generate the electron source, combined with the rapid development of more compact, efficient and higher repetition rate high power laser systems will make this system feasible for applications in the field. Content includes material subject to Dstl (c) Crown copyright (2014). Licensed under the terms of the Open Government Licence except where otherwise stated. To view this licence, visit http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@ nationalarchives.gsi.gov.uk.
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Affiliation(s)
- R M Deas
- Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK
| | - L A Wilson
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - D Rusby
- SUPA Department of Physics, University of Strathclyde, Glasgow, UK
| | - A Alejo
- Department of Physics and Astronomy, Queens University of Belfast, Belfast, UK
| | - R Allott
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - P P Black
- Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK
| | - S E Black
- Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK
| | - M Borghesi
- Department of Physics and Astronomy, Queens University of Belfast, Belfast, UK
| | - C M Brenner
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - J Bryant
- Blackett Laboratory, Imperial College London, London, UK
| | - R J Clarke
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - J C Collier
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - B Edwards
- Innovations, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - P Foster
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - J Greenhalgh
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - C Hernandez-Gomez
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - S Kar
- Department of Physics and Astronomy, Queens University of Belfast, Belfast, UK
| | - D Lockley
- Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK
| | - R M Moss
- Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Z Najmudin
- Blackett Laboratory, Imperial College London, London, UK
| | - R Pattathil
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - D Symes
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK
| | - M D Whittle
- Security Sciences Department, DSTL, Fort Halstead, Sevenoaks, Kent, UK
| | - J C Wood
- Blackett Laboratory, Imperial College London, London, UK
| | - P McKenna
- SUPA Department of Physics, University of Strathclyde, Glasgow, UK
| | - D Neely
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, UK
- SUPA Department of Physics, University of Strathclyde, Glasgow, UK
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15
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Abstract
In this study, we consider suspensions of swimming microorganisms in situations where we might expect the promotion of two-dimensional flow, such as within thin fluid films. Given that two-dimensional, inertialess flows are notoriously long-ranged (although not afflicted by Stokes paradox in the case of self-motile bodies), this raises interesting questions around the care which must be taken with the semi-dilute assumption in such situations. Adopting the prototype squirmer as a model of a swimming microorganisms of the type previously considered, we find that although the flowfield decays algebraically with the characteristic separation distance between microorganisms, there remains a finite interaction between the squirmers even at asymptotically large distances. This finding is further borne out by asymptotic analysis, which confirms that the limiting form of the far-field interaction depends solely upon the relative orientation between the microorganisms. Those which swim in the same general direction are seen to experience very large lateral displacements (many times the size of the displacements experienced owing to interactions between less well-aligned swimmers). This clearly has potential implications for very dilute suspensions in which squirmers become broadly aligned in their swimming direction (e.g. during chemotaxis). We show that hydrodynamically enhanced cell spreading, previously reported for denser suspensions, can persist even at extreme dilutions. Moreover, we demonstrate that this induced spreading can continue in the presence of potentially decohering Brownian effects.
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Affiliation(s)
- R. J. Clarke
- Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - M. D. Finn
- School of Mathematical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - M. MacDonald
- School of Engineering, University of Melbourne, Victoria, Australia
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16
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Günther MM, Britz A, Clarke RJ, Harres K, Hoffmeister G, Nürnberg F, Otten A, Pelka A, Roth M, Vogt K. NAIS: nuclear activation-based imaging spectroscopy. Rev Sci Instrum 2013; 84:073305. [PMID: 23902056 DOI: 10.1063/1.4815826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In recent years, the development of high power laser systems led to focussed intensities of more than 10(22) W/cm(2) at high pulse energies. Furthermore, both, the advanced high power lasers and the development of sophisticated laser particle acceleration mechanisms facilitate the generation of high energetic particle beams at high fluxes. The challenge of imaging detector systems is to acquire the properties of the high flux beam spatially and spectrally resolved. The limitations of most detector systems are saturation effects. These conventional detectors are based on scintillators, semiconductors, or radiation sensitive films. We present a nuclear activation-based imaging spectroscopy method, which is called NAIS, for the characterization of laser accelerated proton beams. The offline detector system is a combination of stacked metal foils and imaging plates (IP). After the irradiation of the stacked foils they become activated by nuclear reactions, emitting gamma decay radiation. In the next step, an autoradiography of the activated foils using IPs and an analysis routine lead to a spectrally and spatially resolved beam profile. In addition, we present an absolute calibration method for IPs.
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Affiliation(s)
- M M Günther
- Institut für Kernphysik, Schlossgartenstr. 9, Technische Universität Darmstadt, D-64289 Darmstadt, Germany.
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17
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Palmer CAJ, Schreiber J, Nagel SR, Dover NP, Bellei C, Beg FN, Bott S, Clarke RJ, Dangor AE, Hassan SM, Hilz P, Jung D, Kneip S, Mangles SPD, Lancaster KL, Rehman A, Robinson APL, Spindloe C, Szerypo J, Tatarakis M, Yeung M, Zepf M, Najmudin Z. Rayleigh-Taylor instability of an ultrathin foil accelerated by the radiation pressure of an intense laser. Phys Rev Lett 2012; 108:225002. [PMID: 23003606 DOI: 10.1103/physrevlett.108.225002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Indexed: 06/01/2023]
Abstract
We report experimental evidence for a Rayleigh-Taylor-like instability driven by radiation pressure of an ultraintense (10(21) W/cm(2)) laser pulse. The instability is witnessed by the highly modulated profile of the accelerated proton beam produced when the laser irradiates a 5 nm diamondlike carbon (90% C, 10% H) target. Clear anticorrelation between bubblelike modulations of the proton beam and transmitted laser profile further demonstrate the role of the radiation pressure in modulating the foil. Measurements of the modulation wavelength, and of the acceleration from Doppler-broadening of back-reflected light, agree quantitatively with particle-in-cell simulations performed for our experimental parameters and which confirm the existence of this instability.
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Affiliation(s)
- C A J Palmer
- Blackett Laboratory, Imperial College, London SW7 2BW, United Kingdom
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18
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Quinn K, Romagnani L, Ramakrishna B, Sarri G, Dieckmann ME, Wilson PA, Fuchs J, Lancia L, Pipahl A, Toncian T, Willi O, Clarke RJ, Notley M, Macchi A, Borghesi M. Weibel-induced filamentation during an ultrafast laser-driven plasma expansion. Phys Rev Lett 2012; 108:135001. [PMID: 22540706 DOI: 10.1103/physrevlett.108.135001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Indexed: 05/31/2023]
Abstract
The development of current instabilities behind the front of a cylindrically expanding plasma has been investigated experimentally via proton probing techniques. A multitude of tubelike filamentary structures is observed to form behind the front of a plasma created by irradiating solid-density wire targets with a high-intensity (I ~ 10(19) W/cm(2)), picosecond-duration laser pulse. These filaments exhibit a remarkable degree of stability, persisting for several tens of picoseconds, and appear to be magnetized over a filament length corresponding to several filament radii. Particle-in-cell simulations indicate that their formation can be attributed to a Weibel instability driven by a thermal anisotropy of the electron population. We suggest that these results may have implications in astrophysical scenarios, particularly concerning the problem of the generation of strong, spatially extended and sustained magnetic fields in astrophysical jets.
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Affiliation(s)
- K Quinn
- Centre for Plasma Physics, School of Mathematics and Physics, The Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
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19
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Abstract
The simple model involving a moving rigid particle, separated from a compliant wall by a thin film of viscous fluid, has previously been applied successfully to a number of important problems. For example, transport of blood cells, particle clearance in the lungs and the late stages of particle sedimentation. Considerable fluid forces are generated in the film, causing the compliant surface to deform. Hence, the usual goal is derivation and solution of an appropriate deformation evolution equation. In the applications considered to-date, however, flow inertia is neglected as flow speeds are not especially high. In this study, we are interested in regimes where unsteady flow inertia is significant, such as found in certain microdevices or thermal excitation of light particles. We present a novel model, which for the first time accounts for inertial effects in both the flow, and the deformable surface. The significant role that inertia plays is fully illustrated through surface deformation profiles, computed under a variety of parameter regimes, as well as calculations of associated hydrodynamic loading. Frequency response curves are seen to exhibit distinct shifts in resonant frequency and quality factor under different levels of inertia, a finding which we believe has important practical implications.
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Affiliation(s)
- R. J. Clarke
- Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - S. Potnis
- Department of Physics, University of Toronto, Toronto, Canada
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20
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Hohenberger M, Symes DR, Lazarus J, Doyle HW, Carley RE, Moore AS, Gumbrell ET, Notley MM, Clarke RJ, Dunne M, Smith RA. Observation of a velocity domain cooling instability in a radiative shock. Phys Rev Lett 2010; 105:205003. [PMID: 21231241 DOI: 10.1103/physrevlett.105.205003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Indexed: 05/30/2023]
Abstract
We report on experimental investigations into strong, laser-driven, radiative shocks in cluster media. Cylindrical shocks launched with several joules of deposited energy exhibit strong radiative effects including rapid deceleration, radiative preheat, and shell thinning. Using time-resolved propagation data from single-shot streaked Schlieren measurements, we have observed temporal modulations on the shock velocity, which we attribute to the thermal cooling instability, a process which is believed to occur in supernova remnants but until now has not been observed experimentally.
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Affiliation(s)
- M Hohenberger
- Laser Consortium, Blackett Laboratory, Imperial College, London SW7 2BZ, United Kingdom.
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21
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Hernandez-Gomez C, Blake SP, Chekhlov O, Clarke RJ, Dunne AM, Galimberti M, Hancock S, Heathcote R, Holligan P, Lyachev A, Matousek P, Musgrave IO, Neely D, Norreys PA, Ross I, Tang Y, Winstone TB, Wyborn BE, Collier J. The Vulcan 10 PW project. ACTA ACUST UNITED AC 2010. [DOI: 10.1088/1742-6596/244/3/032006] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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22
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Nilson PM, Mangles SPD, Willingale L, Kaluza MC, Thomas AGR, Tatarakis M, Najmudin Z, Clarke RJ, Lancaster KL, Karsch S, Schreiber J, Evans RG, Dangor AE, Krushelnick K. Generation of ultrahigh-velocity ionizing shocks with petawatt-class laser pulses. Phys Rev Lett 2009; 103:255001. [PMID: 20366258 DOI: 10.1103/physrevlett.103.255001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Indexed: 05/29/2023]
Abstract
Ultrahigh-velocity shock waves (approximately 10,000 km/s or 0.03c) are generated by focusing a 350-TW laser pulse into low-density helium gas. The collisionless ultrahigh-Mach-number electrostatic shock propagates from the plasma into the surrounding gas, ionizing gas as it becomes collisional. The shock undergoes a corrugation instability due to propagation of the ionizing shock within the gas (the Dyakov-Kontorovich instability). This system may be relevant to the study of very high-Mach-number ionizing shocks in astrophysical situations.
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Affiliation(s)
- P M Nilson
- Department of Physics, Imperial College, London SW7 2AZ United Kingdom
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23
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Quinn K, Wilson PA, Ramakrishna B, Romagnani L, Sarri G, Cecchetti CA, Lancia L, Fuchs J, Pipahl A, Toncian T, Willi O, Clarke RJ, Neely D, Notley M, Gallegos P, Carroll DC, Quinn MN, Yuan XH, McKenna P, Borghesi M. Modified proton radiography arrangement for the detection of ultrafast field fronts. Rev Sci Instrum 2009; 80:113506. [PMID: 19947730 DOI: 10.1063/1.3262630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The experimental arrangement for the investigation of high-field laser-induced processes using a broadband proton probe beam has been modified to enable the detection of the ultrafast motion of field fronts. It is typical in such experiments for the target to be oriented perpendicularly with respect to the principal axis of the probe beam. It is demonstrated here, however, that the temporal imaging properties of the diagnostic arrangement are altered drastically by placing the axis (or plane) of the target at an oblique angle to the transverse plane of the probe beam. In particular, the detection of the motion of a laser-driven field front along a wire at a velocity of (0.95+/-0.05)c is described.
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Affiliation(s)
- K Quinn
- Department of Physics and Astronomy, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
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Kneip S, Nagel SR, Martins SF, Mangles SPD, Bellei C, Chekhlov O, Clarke RJ, Delerue N, Divall EJ, Doucas G, Ertel K, Fiuza F, Fonseca R, Foster P, Hawkes SJ, Hooker CJ, Krushelnick K, Mori WB, Palmer CAJ, Phuoc KT, Rajeev PP, Schreiber J, Streeter MJV, Urner D, Vieira J, Silva LO, Najmudin Z. Near-GeV acceleration of electrons by a nonlinear plasma wave driven by a self-guided laser pulse. Phys Rev Lett 2009; 103:035002. [PMID: 19659287 DOI: 10.1103/physrevlett.103.035002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Indexed: 05/28/2023]
Abstract
The acceleration of electrons to approximately 0.8 GeV has been observed in a self-injecting laser wakefield accelerator driven at a plasma density of 5.5x10(18) cm(-3) by a 10 J, 55 fs, 800 nm laser pulse in the blowout regime. The laser pulse is found to be self-guided for 1 cm (>10zR), by measurement of a single filament containing >30% of the initial laser energy at this distance. Three-dimensional particle in cell simulations show that the intensity within the guided filament is amplified beyond its initial focused value to a normalized vector potential of a0>6, thus driving a highly nonlinear plasma wave.
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Affiliation(s)
- S Kneip
- The Blackett Laboratory, Imperial College London, London, SW7 2BZ, United Kingdom
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25
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Quinn K, Wilson PA, Cecchetti CA, Ramakrishna B, Romagnani L, Sarri G, Lancia L, Fuchs J, Pipahl A, Toncian T, Willi O, Clarke RJ, Neely D, Notley M, Gallegos P, Carroll DC, Quinn MN, Yuan XH, McKenna P, Liseykina TV, Macchi A, Borghesi M. Laser-driven ultrafast field propagation on solid surfaces. Phys Rev Lett 2009; 102:194801. [PMID: 19518962 DOI: 10.1103/physrevlett.102.194801] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Indexed: 05/27/2023]
Abstract
The interaction of a 3x10;{19} W/cm;{2} laser pulse with a metallic wire has been investigated using proton radiography. The pulse is observed to drive the propagation of a highly transient field along the wire at the speed of light. Within a temporal window of 20 ps, the current driven by this field rises to its peak magnitude approximately 10;{4} A before decaying to below measurable levels. Supported by particle-in-cell simulation results and simple theoretical reasoning, the transient field measured is interpreted as a charge-neutralizing disturbance propagated away from the interaction region as a result of the permanent loss of a small fraction of the laser-accelerated hot electron population to vacuum.
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Affiliation(s)
- K Quinn
- Department of Physics and Astronomy, Queen's University Belfast, Belfast BT7 1NN, United Kingdom.
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26
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Willingale L, Nagel SR, Thomas AGR, Bellei C, Clarke RJ, Dangor AE, Heathcote R, Kaluza MC, Kamperidis C, Kneip S, Krushelnick K, Lopes N, Mangles SPD, Nazarov W, Nilson PM, Najmudin Z. Characterization of high-intensity laser propagation in the relativistic transparent regime through measurements of energetic proton beams. Phys Rev Lett 2009; 102:125002. [PMID: 19392290 DOI: 10.1103/physrevlett.102.125002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Revised: 01/11/2009] [Indexed: 05/27/2023]
Abstract
Experiments were performed to investigate the propagation of a high intensity (I approximately 10(21) W cm(-2)) laser in foam targets with densities ranging from 0.9n(c) to 30n(c). Proton acceleration was used to diagnose the interaction. An improvement in proton beam energy and efficiency is observed for the lowest density foam (n(e)=0.9n(c)), compared to higher density foams. Simulations show that the laser beam penetrates deeper into the target due to its relativistic propagation and results in greater collimation of the ensuing hot electrons. This results in the rear surface accelerating electric field being larger, increasing the efficiency of the acceleration. Enhanced collimation of the ions is seen to be due to the self-generated azimuthal magnetic and electric fields at the rear of the target.
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Affiliation(s)
- L Willingale
- Blackett Laboratory, Imperial College, London SW7 2AZ, UK
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27
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Clarke RJ, Jensen OE, Billingham J. Three-dimensional elastohydrodynamics of a thin plate oscillating above a wall. Phys Rev E Stat Nonlin Soft Matter Phys 2008; 78:056310. [PMID: 19113219 DOI: 10.1103/physreve.78.056310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Indexed: 05/27/2023]
Abstract
We consider deflections of a thin rectangular elastic plate that is submerged within a Newtonian fluid. The plate is clamped along one edge and supported horizontally over a plane horizontal wall. We consider both external driving, where the clamped edge is vibrated vertically at high frequencies, and thermal driving, where the plate fluctuates under Brownian motion. In both cases, the amplitude of oscillation is assumed sufficiently small that the resulting flow has little convective inertia, although the oscillation frequency is sufficiently high to generate substantial unsteady inertia in the flow, a common scenario in many nano- and microdevices. We exploit the plate's thinness to develop an integral-equation representation for the three-dimensional flow (a so-called thin-plate theory) which offers considerable computational savings over a full boundary-integral formulation. Limiting cases of high oscillation frequencies and small wall-plate separation distances are studied separately, leading to further simplified descriptions for the hydrodynamics. We validate these reduced integral representations against full boundary-integral computations, and identify the parameter ranges over which these simplified formulations are valid. Addressing the full flow-structure interaction, we also examine the limits of simpler two-dimensional hydrodynamic models. We compare the responses of a narrow plate under two- and three-dimensional hydrodynamic loading, and report differences in the frequency response curves that occur when the plate operates in water, in contrast to the excellent agreement observed in air.
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Affiliation(s)
- R J Clarke
- Department of Engineering Science, University of Auckland, Auckland, New Zealand.
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Kar S, Markey K, Simpson PT, Bellei C, Green JS, Nagel SR, Kneip S, Carroll DC, Dromey B, Willingale L, Clark EL, McKenna P, Najmudin Z, Krushelnick K, Norreys P, Clarke RJ, Neely D, Borghesi M, Zepf M. Dynamic control of laser-produced proton beams. Phys Rev Lett 2008; 100:105004. [PMID: 18352198 DOI: 10.1103/physrevlett.100.105004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Indexed: 05/26/2023]
Abstract
The emission characteristics of intense laser driven protons are controlled using ultrastrong (of the order of 10(9) V/m) electrostatic fields varying on a few ps time scale. The field structures are achieved by exploiting the high potential of the target (reaching multi-MV during the laser interaction). Suitably shaped targets result in a reduction in the proton beam divergence, and hence an increase in proton flux while preserving the high beam quality. The peak focusing power and its temporal variation are shown to depend on the target characteristics, allowing for the collimation of the inherently highly divergent beam and the design of achromatic electrostatic lenses.
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Affiliation(s)
- S Kar
- The Queen's University of Belfast, Belfast BT7 1NN, United Kingdom
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29
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Reynolds SC, Clarke RJ, Kuman KA. The view from the Lincoln Cave: mid- to late Pleistocene fossil deposits from Sterkfontein hominid site, South Africa. J Hum Evol 2007; 53:260-71. [PMID: 17624409 DOI: 10.1016/j.jhevol.2007.02.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Revised: 02/03/2007] [Accepted: 02/25/2007] [Indexed: 10/23/2022]
Abstract
The Lincoln-Fault cave system lies adjacent to the Sterkfontein Cave system in the Cradle of Humankind World Heritage Site, Gauteng Province, South Africa. Lincoln Cave contains a mid- to late Pleistocene fossiliferous deposit which has been dated using uranium series methods to between 252,600+/-35,600 and 115,300+/-7,700 years old. Although speleologists presumed that there was no connection between the Lincoln Cave and Sterkfontein Cave systems, results of excavations conducted in 1997 suggest a link between the deposits. Detailed comparisons of artifacts, fauna, hominid material, and a statistical correspondence analysis (CA) of the macromammalian fauna in the deposits strongly support this hypothesis. The recovery of Early Acheulean-type artifacts from the Lincoln Cave suggests that older artifacts eroded out of Sterkfontein Member 5 West and were redeposited into the younger Lincoln Cave deposits. The close physical proximity of these deposits, and the nature of the material recovered from them, indicates that the material was probably redeposited via a link between the two cave systems. Although faunal mixing is present, it is possible to say that large carnivorans become more scarce at Sterkfontein during the mid- to late Pleistocene, while small canids and felids appear to become more abundant, indicating that large and small carnivorans probably varied their use of the site through time. This may also reflect an increasing presence of humans in the Sterkfontein area during the mid- to late Pleistocene.
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Affiliation(s)
- S C Reynolds
- School of Anatomical Sciences, University of the Witwatersrand Medical School, South Africa.
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30
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Saiz EG, Khattak FY, Gregori G, Bandyopadhyay S, Clarke RJ, Fell B, Freeman RR, Jeffries J, Jung D, Notley MM, Weber RL, van Woerkom L, Riley D. Wide angle crystal spectrometer for angularly and spectrally resolved X-ray scattering experiments. Rev Sci Instrum 2007; 78:095101. [PMID: 17902968 DOI: 10.1063/1.2783773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
A novel wide angle spectrometer has been implemented with a highly oriented pyrolytic graphite crystal coupled to an image plate. This spectrometer has allowed us to look at the energy resolved spectrum of scattered x rays from a dense plasma over a wide range of angles (approximately 30 degrees ) in a single shot. Using this spectrometer we were able to observe the temporal evolution of the angular scatter cross section from a laser shocked foil. A spectrometer of this type may also be useful in investigations of x-ray line transfer from laser-plasmas experiments.
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Affiliation(s)
- E García Saiz
- School of Mathematics and Physics, Queen's University of Belfast, Belfast BT7 1NN, United Kingdom.
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31
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Dromey B, Kar S, Bellei C, Carroll DC, Clarke RJ, Green JS, Kneip S, Markey K, Nagel SR, Simpson PT, Willingale L, McKenna P, Neely D, Najmudin Z, Krushelnick K, Norreys PA, Zepf M. Bright multi-keV harmonic generation from relativistically oscillating plasma surfaces. Phys Rev Lett 2007; 99:085001. [PMID: 17930952 DOI: 10.1103/physrevlett.99.085001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Indexed: 05/25/2023]
Abstract
The first evidence of x-ray harmonic radiation extending to 3.3 A, 3.8 keV (order n>3200) from petawatt class laser-solid interactions is presented, exhibiting relativistic limit efficiency scaling (eta approximately n{-2.5}-n{-3}) at multi-keV energies. This scaling holds up to a maximum order, n{RO} approximately 8{1/2}gamma;{3}, where gamma is the relativistic Lorentz factor, above which the first evidence of an intensity dependent efficiency rollover is observed. The coherent nature of the generated harmonics is demonstrated by the highly directional beamed emission, which for photon energy hnu>1 keV is found to be into a cone angle approximately 4 degrees , significantly less than that of the incident laser cone (20 degrees ).
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Affiliation(s)
- B Dromey
- Department of Physics and Astronomy, Queens University, Belfast, UK
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32
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McKenna P, Carroll DC, Clarke RJ, Evans RG, Ledingham KWD, Lindau F, Lundh O, McCanny T, Neely D, Robinson APL, Robson L, Simpson PT, Wahlström CG, Zepf M. Lateral electron transport in high-intensity laser-irradiated foils diagnosed by ion emission. Phys Rev Lett 2007; 98:145001. [PMID: 17501281 DOI: 10.1103/physrevlett.98.145001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2006] [Indexed: 05/15/2023]
Abstract
An experimental investigation of lateral electron transport in thin metallic foil targets irradiated by ultraintense (>or=10(19) W/cm2) laser pulses is reported. Two-dimensional spatially resolved ion emission measurements are used to quantify electric-field generation resulting from electron transport. The measurement of large electric fields ( approximately 0.1 TV/m) millimeters from the laser focus reveals that lateral energy transport continues long after the laser pulse has decayed. Numerical simulations confirm a very strong enhancement of electron density and electric field at the edges of the target.
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Affiliation(s)
- P McKenna
- SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG, United Kingdom
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33
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Lancaster KL, Green JS, Hey DS, Akli KU, Davies JR, Clarke RJ, Freeman RR, Habara H, Key MH, Kodama R, Krushelnick K, Murphy CD, Nakatsutsumi M, Simpson P, Stephens R, Stoeckl C, Yabuuchi T, Zepf M, Norreys PA. Measurements of energy transport patterns in solid density laser plasma interactions at intensities of 5x10(20) W cm-2. Phys Rev Lett 2007; 98:125002. [PMID: 17501132 DOI: 10.1103/physrevlett.98.125002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Indexed: 05/15/2023]
Abstract
Kalpha x-ray emission, extreme ultraviolet emission, and plasma imaging techniques have been used to diagnose energy transport patterns in copper foils ranging in thickness from 5 to 75 microm for intensities up to 5x10(20) W cm-2. The Kalpha emission and shadowgrams both indicate a larger divergence angle than that reported in the literature at lower intensities [R. Stephens, Phys. Rev. E 69, 066414 (2004)]. Foils 5 microm thick show triple-humped plasma expansion patterns at the back and front surfaces. Hybrid code modeling shows that this can be attributed to an increase in the mean energy of the fast electrons emitted at large radii, which only have sufficient energy to form a plasma in such thin targets.
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Affiliation(s)
- K L Lancaster
- CCLRC, Rutherford Appleton Laboratory, Chilton, Oxon, OX11 0QX, UK
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34
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Black RM, Brewster K, Clarke RJ, Harrison JM. THE CHEMISTRY OF 1,1′-THIOBIS(2-CHLOROETHANE) (SULPHUR MUSTARD) PART II.1 THE SYNTHESIS OF SOME CONJUGATES WITH CYSTEINE, N-ACETYLCYSTEINE AND N-ACETYLCYSTEINE METHYL ESTER. PHOSPHORUS SULFUR 2006. [DOI: 10.1080/10426509208034495] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- R. M. Black
- a Chemical and Biological Defence Establishment , Porton Down, Salisbury , Wilts , SP4 OJQ
| | - K. Brewster
- a Chemical and Biological Defence Establishment , Porton Down, Salisbury , Wilts , SP4 OJQ
| | - R. J. Clarke
- a Chemical and Biological Defence Establishment , Porton Down, Salisbury , Wilts , SP4 OJQ
| | - J. M. Harrison
- a Chemical and Biological Defence Establishment , Porton Down, Salisbury , Wilts , SP4 OJQ
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35
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Clarke RJ, Neely D, Edwards RD, Wright PNM, Ledingham KWD, Heathcote R, McKenna P, Danson CN, Brummitt PA, Collier JL, Hatton PE, Hawkes SJ, Hernandez-Gomez C, Holligan P, Hutchinson MHR, Kidd AK, Lester WJ, Neville DR, Norreys PA, Pepler DA, Winstone TB, Wyatt RWW, Wyborn BE. Radiological characterisation of photon radiation from ultra-high-intensity laser-plasma and nuclear interactions. J Radiol Prot 2006; 26:277-86. [PMID: 16926470 DOI: 10.1088/0952-4746/26/3/002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
With the increasing number of multi-terawatt (10(12) W) and petawatt (10(15) W) laser interaction facilities being built, the need for a detailed understanding of the potential radiological hazards is required and their impact on personnel is of major concern. Experiments at a number of facilities are being undertaken to achieve this aim. This paper describes the recent work completed on the Vulcan petawatt laser system at the CCLRC Rutherford Appleton Laboratory, where photon doses of up to 43 mSv at 1 m per shot have been measured during commissioning studies. It also overviews the shielding in place on the facility in order to comply with the Ionising Radiation Regulations 1999 (IRR99), maintaining a dose to personnel of less than 1 mSv yr(-1) and as low as reasonably practicable (ALARP).
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Affiliation(s)
- R J Clarke
- CCLRC Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, UK.
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36
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Willingale L, Mangles SPD, Nilson PM, Clarke RJ, Dangor AE, Kaluza MC, Karsch S, Lancaster KL, Mori WB, Najmudin Z, Schreiber J, Thomas AGR, Wei MS, Krushelnick K. Collimated multi-MeV ion beams from high-intensity laser interactions with underdense plasma. Phys Rev Lett 2006; 96:245002. [PMID: 16907250 DOI: 10.1103/physrevlett.96.245002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Indexed: 05/11/2023]
Abstract
A beam of multi-MeV helium ions has been observed from the interaction of a short-pulse high-intensity laser pulse with underdense helium plasma. The ion beam was found to have a maximum energy for He2+ of (40(+3)(-8)) MeV and was directional along the laser propagation path, with the highest energy ions being collimated to a cone of less than 10 degrees. 2D particle-in-cell simulations show that the ions are accelerated by a sheath electric field that is produced at the back of the gas target. This electric field is generated by transfer of laser energy to a hot electron beam, which exits the target generating large space-charge fields normal to its boundary.
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Affiliation(s)
- L Willingale
- Blackett Laboratory, Imperial College London, London SW7 2BZ, United Kingdom
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37
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Hernandez-Gomez C, Brummitt PA, Canny DJ, Clarke RJ, Collier J, Danson CN, Dunne AM, Fell B, Frackiewicz AJ, Hancock S, Hawkes S, Heathcote R, Holligan P, Hutchinson MH, Kidd A, Lester WJ, Musgrave IO, Neely D, Neville DR, Norreys PA, Pepler DA, Reason CJ, Shaikh W, Winstone TB, Wyborn BE. Vulcan petawatt-operation and development. ACTA ACUST UNITED AC 2006. [DOI: 10.1051/jp4:2006133114] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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38
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Martinolli E, Koenig M, Baton SD, Santos JJ, Amiranoff F, Batani D, Perelli-Cippo E, Scianitti F, Gremillet L, Mélizzi R, Decoster A, Rousseaux C, Hall TA, Key MH, Snavely R, MacKinnon AJ, Freeman RR, King JA, Stephens R, Neely D, Clarke RJ. Fast-electron transport and heating of solid targets in high-intensity laser interactions measured by K alpha fluorescence. Phys Rev E Stat Nonlin Soft Matter Phys 2006; 73:046402. [PMID: 16711934 DOI: 10.1103/physreve.73.046402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 11/21/2005] [Indexed: 05/09/2023]
Abstract
We present experimental results on fast-electron energy deposition into solid targets in ultrahigh intensity laser-matter interaction. X-ray K alpha emission spectroscopy with absolute photon counting served to diagnose fast-electron propagation in multilayered targets. Target heating was measured from ionization-shifted K alpha emission. Data show a 200 microm fast-electron range in solid Al. The relative intensities of spectrally shifted Al K alpha lines imply a mean temperature of a few tens of eV up to a 100 microm depth. Experimental results suggest refluxing of the electron beam at target rear side. They were compared with the predictions of both a collisional Monte Carlo and a collisional-electromagnetic, particle-fluid transport code. The validity of the code modeling of heating in such highly transient conditions is discussed.
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Affiliation(s)
- E Martinolli
- Laboratoire pour l'Utilisation des Lasers Intenses, UMR7605, CNRS-CEA-Université Paris VI-Ecole Polytechnique, 91128 Palaiseau, France
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39
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Clarke RJ, Jensen OE, Billingham J, Pearson AP, Williams PM. Stochastic elastohydrodynamics of a microcantilever oscillating near a wall. Phys Rev Lett 2006; 96:050801. [PMID: 16486916 DOI: 10.1103/physrevlett.96.050801] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Indexed: 05/06/2023]
Abstract
We consider the thermally driven motion of a microcantilever in a fluid environment near a wall, a configuration characteristic of the atomic force microscope. A theoretical model is presented which accounts for hydrodynamic interactions between the cantilever and wall over a wide range of frequencies and which exploits the fluctuation-dissipation theorem to capture the Brownian dynamics of the coupled fluid-cantilever system. Model predictions are tested against experimental thermal spectra for a cantilever in air and water. The model shows how, in a liquid environment, the effects of non-delta-correlated Brownian forcing appear in the power spectrum, particularly at low frequencies. The model also predicts accurately changes in the spectrum in liquid arising through hydrodynamic wall effects, which we show are strongly mediated by the angle at which the cantilever is tilted relative to the wall.
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Affiliation(s)
- R J Clarke
- School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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40
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41
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McKenna P, Ledingham KWD, Shimizu S, Yang JM, Robson L, McCanny T, Galy J, Magill J, Clarke RJ, Neely D, Norreys PA, Singhal RP, Krushelnick K, Wei MS. Broad energy spectrum of laser-accelerated protons for spallation-related physics. Phys Rev Lett 2005; 94:084801. [PMID: 15783897 DOI: 10.1103/physrevlett.94.084801] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Indexed: 05/24/2023]
Abstract
A beam of MeV protons, accelerated by ultraintense laser-pulse interactions with a thin target foil, is used to investigate nuclear reactions of interest for spallation physics. The laser-generated proton beam is shown (protons were measured) to have a broad energy distribution, which closely resembles the expected energy spectrum of evaporative protons (below 50 MeV) produced in GeV-proton-induced spallation reactions. The protons are used to quantify the distribution of residual radioisotopes produced in a representative spallation target (Pb), and the results are compared with calculated predictions based on spectra modeled with nuclear Monte Carlo codes. Laser-plasma particle accelerators are shown to provide data relevant to the design and development of accelerator driven systems.
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Affiliation(s)
- P McKenna
- Department of Physics, University of Strathclyde, Glasgow G4 0NG, Scotland, United Kingdom.
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42
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Riley D, Angulo-Gareta JJ, Khattak FY, Lamb MJ, Foster PS, Divall EJ, Hooker CJ, Langley AJ, Clarke RJ, Neely D. Kalpha yields from Ti foils irradiated with ultrashort laser pulses. Phys Rev E Stat Nonlin Soft Matter Phys 2005; 71:016406. [PMID: 15697734 DOI: 10.1103/physreve.71.016406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Indexed: 05/24/2023]
Abstract
We have studied the emission of Kalpha radiation from Ti foils irradiated with ultrashort (45 fs) laser pulses. We utilized the fundamental (800 nm) light from a Ti:sapphire laser on bare foils and foils coated with a thin layer of parylene E (CH). The focusing was varied widely to give a range of intensities from approximately 10(15) - 10(19) W cm(-2). Our results show a conversion efficiency of laser to Kalpha energy of approximately 10(-4) at tight focus for both types of targets. In addition, the coated targets exhibited strong secondary peaks of conversion at large defocus, which we believe are due to modification of the extent of preformed plasma due to the dielectric nature of the plastic layer. This in turn affects the level of resonance absorption. A simple model of Kalpha production predicts a much higher conversion than seen experimentally and possible reasons for this are discussed.
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Affiliation(s)
- D Riley
- School of Mathematics and Physics, Queen's University of Belfast, University Road, Belfast, BT7 1NN, Northern Ireland.
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Wei MS, Mangles SPD, Najmudin Z, Walton B, Gopal A, Tatarakis M, Dangor AE, Clark EL, Evans RG, Fritzler S, Clarke RJ, Hernandez-Gomez C, Neely D, Mori W, Tzoufras M, Krushelnick K. Ion acceleration by collisionless shocks in high-intensity-laser-underdense-plasma interaction. Phys Rev Lett 2004; 93:155003. [PMID: 15524892 DOI: 10.1103/physrevlett.93.155003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2004] [Indexed: 05/24/2023]
Abstract
Ion acceleration by the interaction of an ultraintense short-pulse laser with an underdense-plasma has been studied at intensities up to 3 x 10(20) W/cm(2). Helium ions having a maximum energy of 13.2+/-1.0 MeV were measured at an angle of 100 degrees from the laser propagation direction. The maximum ion energy scaled with plasma density as n(0.70+/-0.05)(e). Two-dimensional particle-in-cell simulations suggest that multiple collisionless shocks are formed at high density. The interaction of shocks is responsible for the observed plateau structure in the ion spectrum and leads to an enhanced ion acceleration beyond that possible by the ponderomotive potential of the laser alone.
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Affiliation(s)
- M S Wei
- Blackett Laboratory, Imperial College, London SW7 2BZ, UK
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McKenna P, Ledingham KWD, Yang JM, Robson L, McCanny T, Shimizu S, Clarke RJ, Neely D, Spohr K, Chapman R, Singhal RP, Krushelnick K, Wei MS, Norreys PA. Characterization of proton and heavier ion acceleration in ultrahigh-intensity laser interactions with heated target foils. Phys Rev E Stat Nonlin Soft Matter Phys 2004; 70:036405. [PMID: 15524644 DOI: 10.1103/physreve.70.036405] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2004] [Indexed: 05/24/2023]
Abstract
Proton and heavy ion acceleration in ultrahigh intensity ( approximately 2 x 10(20) W cm(-2) ) laser plasma interactions has been investigated using the new petawatt arm of the VULCAN laser. Nuclear activation techniques have been applied to make the first spatially integrated measurements of both proton and heavy ion acceleration from the same laser shots with heated and unheated Fe foil targets. Fe ions with energies greater than 10 MeV per nucleon have been observed. Effects of target heating on the accelerated ion energy spectra and the laser-to-ion energy conversion efficiencies are discussed. The laser-driven production of the long-lived isotope (57 )Co (271 days) via a heavy ion induced reaction is demonstrated.
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Affiliation(s)
- P McKenna
- Department of Physics, University of Strathclyde, Glasgow G4 0NG, United Kingdom.
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McKenna P, Ledingham KWD, McCanny T, Singhal RP, Spencer I, Santala MIK, Beg FN, Krushelnick K, Tatarakis M, Wei MS, Clark EL, Clarke RJ, Lancaster KL, Norreys PA, Spohr K, Chapman R, Zepf M. Demonstration of fusion-evaporation and direct-interaction nuclear reactions using high-intensity laser-plasma-accelerated ion beams. Phys Rev Lett 2003; 91:075006. [PMID: 12935029 DOI: 10.1103/physrevlett.91.075006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2003] [Indexed: 05/24/2023]
Abstract
Heavy-ion induced nuclear reactions in materials exposed to energetic ions produced from high-intensity (approximately 5 x 10(19) W/cm(2)) laser-solid interactions have been experimentally investigated for the first time. Many of the radionuclides produced result from the creation of "compound nuclei" with the subsequent evaporation of proton, neutron, and alpha particles. Results are compared with previous measurements with monochromatic ion beams from a conventional accelerator. Measured nuclide yields are used to diagnose the acceleration of ions from laser-ablated plasma to energies greater than 100 MeV.
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Affiliation(s)
- P McKenna
- Department of Physics, University of Strathclyde, Glasgow G4 0NG, Scotland, UK.
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Abstract
Cosmogenic aluminum-26 and beryllium-10 burial dates of low-lying fossiliferous breccia in the caves at Sterkfontein, South Africa, show that associated hominid fossils accumulated in the Lower Pliocene. These dates indicate that the skeleton StW 573 and newly discovered specimens from Jacovec Cavern have much the same age: approximately 4 million years. These specimens are thus of an age similar to Australopithecus anamensis from East Africa.
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Affiliation(s)
- T C Partridge
- Sterkfontein Research Unit and Climatology Research Group, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg, South Africa.
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Spencer I, Ledingham KWD, McKenna P, McCanny T, Singhal RP, Foster PS, Neely D, Langley AJ, Divall EJ, Hooker CJ, Clarke RJ, Norreys PA, Clark EL, Krushelnick K, Davies JR. Experimental study of proton emission from 60-fs, 200-mJ high-repetition-rate tabletop-laser pulses interacting with solid targets. Phys Rev E Stat Nonlin Soft Matter Phys 2003; 67:046402. [PMID: 12786496 DOI: 10.1103/physreve.67.046402] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2002] [Revised: 11/26/2002] [Indexed: 05/24/2023]
Abstract
Measurements of proton emission have been made from a variety of solid targets irradiated by a 60-fs, 200-mJ, 7 x 10(18)-W cm(-2) laser system operating at 2 Hz. Optimum target conditions were found in terms of target material and thickness. For Mylar targets of thickness 20-40 microm, a maximum proton energy of 1.5 MeV was measured. For aluminum targets, a maximum energy of 950 keV was measured for 12 microm, and for copper, 850 keV for 12.5 microm.
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Affiliation(s)
- I Spencer
- Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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Protsch von Zieten R, Clarke RJ. The oldest complete skeleton of an Australopithecus in Africa (StW 573). Anthropol Anz 2003; 61:7-17. [PMID: 12712769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Although 78 years have elapsed since the discovery at Taung of the Australopithecus africanus, and despite intensive fieldwork in East Africa which resulted in 32 years of non-stop excavation at Sterkfontein, there has not been a discovery to date of a reasonably intact skull and associated skeleton of an ape-man. The following report is an account of an extraordinary series of events that led to the discovery of a complete skeleton on an Australopithecus, and a preliminary assessment of the significance of the fossil, which is still 5 years after its discovery largely embedded in the Member 2 breccia of the Sterkfontein Caves near Krugersdorp, South Africa.
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Affiliation(s)
- R Protsch von Zieten
- Franz Weidenreich, Institute of Anthropology and Human Genetics, University of Frankfurt/M., Germany.
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