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High order modes of intense second harmonic light produced from a plasma aperture

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Matter and radiation at Extremes 2022年第5期7卷 7-16页

作者： E.F.j.Bacon M.King r.Wilson T.P.Frazer r.j.gray P.McKenna SUPA Department of Physics University of StrathclydeGlasgow G40NGUnited Kingdom The Cockcroft Institute Sci-Tech DaresburyWarrington WA44ADUnited Kingdom

Because of their ability to sustain extremely high-amplitude electromagnetic fields and transient density and field profiles,plasma optical components are being developed to amplify,compress,and condition high-power laser *** recently demonstrated the potential to use a relativistic plasma aperture—produced during the interaction of a high-power laser pulse with an ultrathin foil target—to tailor the spatiotemporal properties of the intense fundamental and second-harmonic light generated[Duff et al.,***.10,105(2020)].Herein,we explore numerically the interaction of an intense laser pulse with a preformed aperture target to generate second-harmonic laser light with higher-order spatial *** maximum generation efficiency is found for an aperture diameter close to the full width at half maximum of the laser focus and for a micrometer-scale target *** spatial mode generated is shown to depend strongly on the polarization of the drive laser pulse,which enables changing between a linearly polarized TEM01 mode and a circularly polarized Laguerre–Gaussian LG01 *** demonstrates the use of a plasma aperture to generate intense higher-frequency light with selectable spatial mode structure.

关键词： polarization intense harmonic

reflection of intense laser light from microstructured targets as a potential diagnostic of laser focus and plasma temperature

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High Power Laser Science and Engineering 2019年第1期7卷 10-16页

作者： j.jarrett M.King r.j.gray N.Neumann L.Dhl C.D.Baird T.Ebert M.Hesse A.Tebartz D.r.rusby N.C.Woolsey D.Neely M.roth P.McKenna Department of Physics SUPA University of Strathclyde Institut f¨ur Kernphysik Technische Universit?t Darmstadt York Plasma Institute University of York STFC-rutherford Appleton Laboratory Institut fur Kernphysik Technische Universit?t Darmstadt

The spatial-intensity profile of light reflected during the interaction of an intense laser pulse with a microstructured target is investigated experimentally and the potential to apply this as a diagnostic of the interaction physics is explored numerically. Diffraction and speckle patterns are measured in the specularly reflected light in the cases of targets with regular groove and needle-like structures, respectively, highlighting the potential to use this as a diagnostic of the evolving plasma surface. It is shown, via ray-tracing and numerical modelling, that for a laser focal spot diameter smaller than the periodicity of the target structure, the reflected light patterns can potentially be used to diagnose the degree of plasma expansion, and by extension the local plasma temperature, at the focus of the intense laser light. The reflected patterns could also be used to diagnose the size of the laser focal spot during a high-intensity interaction when using a regular structure with known spacing.

关键词： high power laser laser-solid interactions plasma temperature diagnosis

Effects of target pre-heating and expansion on terahertz radiation production from intense laser-solid interactions

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High Power Laser Science and Engineering 2014年第1期2卷 13-17页

作者： X.H.Yuan Y.Fang D.C.Carroll D.A.MacLellan F.Du N.Booth M.Burza M.Chen r.j.gray Y.F.jin Y.T.Li Y.Liu D.Neely H.Powell G.Scott C.-G.Wahlstrm j.Zhang P.McKenna Z.M.Sheng Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics and Astronomy Shanghai Jiao Tong University Beijing National Laboratory of Condensed Matter Physics Institute of Physics Chinese Academy of Sciences SUPA Department of Physics University of Strathclyde Central Laser Facility Rutherford Appleton Laboratory Department of Physics Lund University

The first experimental measurements of intense(～7 × 1019 W cm-2) laser-driven terahertz(THz) radiation from a solid target which is preheated by an intense pulse of laser-accelerated protons is reported. The total energy of the THz radiation is found to decrease by approximately a factor of 2 compared to a cold target reference. This is attributed to an increase in the scale length of the preformed plasma, driven by proton heating, at the front surface of the target,where the THz radiation is generated. The results show the importance of controlling the preplasma scale length for THz production.

关键词： target heating terahertz radiation

Optimization and control of synchrotron emission in ultraintense laser–solid interactions using machine learning – COrrIGENDUM

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High Power Laser Science and Engineering 2024年第1期12卷 116-116页

作者： j.Goodman M.King E.j.Dolier r.Wilson r.j.gray P.McKenna 不详

Due to an isolated error in the 3D simulation parameters,the laser energy and intensity(calculated using the energy)values were incorrectly stated as 10.9 j and 3×10^(22) W cm^(−2),respectively,in Sections 3.3,7 and *** correct values are 39.8 j and 1.1×10^(23) W cm^(−2).Similarly,the values stated for the higher energy case,109 j and 3×10^(23) W cm^(−2) in Section 7,should be 398 j and 1.1×10^(24) W cm^(−2),respectively.

关键词： Bayesian optimization gamma rays laser-solid interactions machine learning radiation reaction

role of magnetic field evolution on filamentary structure formation in intense laser–foil interactions

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High Power Laser Science and Engineering 2019年第1期7卷 99-106页

作者： M.King N.M.H.Butler r.Wilson r.Capdessus r.j.gray H.W.Powell r.j.Dance H.Padda B.Gonzalez-Izquierdo D.r.rusby N.P.Dover G.S.Hicks O.C.Ettlinger C.Scullion D.C.Carroll Z.Najmudin M.Borghesi D.Neely P.McKenna SUPA Department of Physics University of Strathclyde Central Laser Facility STFC Rutherford Appleton Laboratory The john Adams Institute for Accelerator Science Blackett Laboratory Imperial College London Centre for Plasma Physics Queen's University Belfast

Filamentary structures can form within the beam of protons accelerated during the interaction of an intense laser pulse with an ultrathin foil target. Such behaviour is shown to be dependent upon the formation time of quasi-static magnetic field structures throughout the target volume and the extent of the rear surface proton expansion over the same *** is observed via both numerical and experimental investigations. By controlling the intensity profile of the laser drive,via the use of two temporally separated pulses, both the initial rear surface proton expansion and magnetic field formation time can be varied, resulting in modification to the degree of filamentary structure present within the laser-driven proton beam.

关键词： laser-plasma ion acceleration instabilities

Automated control and optimization of laser-driven ion acceleration

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High Power Laser Science and Engineering 2023年第3期11卷 32-40页

作者： B.Loughran M.j.V.Streeter H.Ahmed S.Astbury M.Balcazar M.Borghesi N.Bourgeois C.B.Curry S.j.D.Dann S.DiIorio N.P.Dover T.Dzelzainis O.C.Ettlinger M.Gauthier L.Giuffrida G.D.Glenn S.H.Glenzer j.S.Green r.j.gray G.S.Hicks C.Hyland V.Istokskaia M.King D.Margarone O.McCusker P.McKenna Z.Najmudin C.Parisuaña P.Parsons C.Spindloe D.r.Symes A.G.r.Thomas F.Treffert N.Xu C.A.j.Palmer School of Mathematics and Physics Queen’s University BelfastBelfastUK Central Laser Facility STFC Rutherford Appleton LaboratoryDidcotUK Gérard Mourou Center for Ultrafast Optical Science University of MichiganAnn ArborMIUSA SLAC National Accelerator Laboratory Menlo ParkCAUSA Department of Electrical and Computer Engineering University of AlbertaEdmontonABCanada The john Adams Institute for Accelerator Science Imperial College LondonLondonUK ELI Beamlines Centre Institute of PhysicsCzech Academy of SciencesDolníBˇrežanyCzech Republic Department of Applied Physics Stanford UniversityStanfordCAUSA Department of Physics SUPAUniversity of StrathclydeGlasgowUK Faculty of Nuclear Sciences and Physical Engineering Czech Technical University in PraguePragueCzech Republic Department of Mechanical Engineering Stanford UniversityStanfordCAUSA Institut für Kernphysik Technische Universität DarmstadtDarmstadtGermany

The interaction of relativistically intense lasers with opaque targets represents a highly non-linear,multi-dimensional parameter *** limits the utility of sequential 1D scanning of experimental parameters for the optimization of secondary radiation,although to-date this has been the accepted methodology due to low data acquisition *** repetition-rate(Hrr)lasers augmented by machine learning present a valuable opportunity for efficient source ***,an automated,Hrr-compatible system produced high-fidelity parameter scans,revealing the influence of laser intensity on target pre-heating and proton generation.A closed-loop Bayesian optimization of maximum proton energy,through control of the laser wavefront and target position,produced proton beams with equivalent maximum energy to manually optimized laser pulses but using only 60%of the laser *** demonstration of automated optimization of laser-driven proton beams is a crucial step towards deeper physical insight and the construction of future radiation sources.

关键词： Bayesian optimization high repetition-rate laser-target interaction laser-driven particle acceleration proton generation

Versatile tape-drive target for high-repetition-rate laser-driven proton acceleration

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High Power Laser Science and Engineering 2023年第4期11卷 59-69页

作者： N.Xu M.j.V.Streeter O.C.Ettlinger H.Ahmed S.Astbury M.Borghesi N.Bourgeois C.B.Curry S.j.D.Dann N.P.Dover T.Dzelzainis V.Istokskaia M.Gauthier L.Giuffrida G.D.Glenn S.H.Glenzer r.j.gray j.S.Green G.S.Hicks C.Hyland M.King B.Loughran D.Margarone O.McCusker P.McKenna C.Parisuaña P.Parsons C.Spindloe D.r.Symes F.Treffert C.A.j.Palmer Z.Najmudin john Adams Institute for Accelerator Science Blackett LaboratoryImperial College LondonLondonUK School of Maths and Physics Queen’s University BelfastBelfastUK Central Laser Facility STFC Rutherford Appleton LaboratoryDidcotUK SLAC National Accelerator Laboratory Menlo ParkUSA ELI Beamlines Centre Institute of PhysicsCASDolni BrezanyCzech Republic Faculty of Nuclear Sciences and Physical Engineering Czech Technical University in PraguePragueCzech Republic Department of Physics SUPAUniversity of StrathclydeGlasgowUK Department of Mechanical Engineering Stanford UniversityStanfordUSA Department of Applied Physics Stanford UniversityStanfordUSA Department of Electrical and Computer Engineering University of AlbertaEdmontonCanada Institut für Kernphysik Technische Universität DarmstadtDarmstadtGermany

We present the development and characterization of a high-stability,multi-material,multi-thickness tape-drive target for laser-driven acceleration at repetition rates of up to 100 *** tape surface position was measured to be stable on the sub-micrometre scale,compatible with the high-numerical aperture focusing geometries required to achieve relativistic intensity interactions with the pulse energy available in current multi-Hz and near-future higher repetition-rate lasers(>kHz).Long-term drift was characterized at 100 Hz demonstrating suitability for operation over extended *** target was continuously operated at up to 5 Hz in a recent experiment for 70,000 shots without intervention by the experimental team,with the exception of tape replacement,producing the largest data-set of relativistically intense laser–solid foil measurements to *** tape drive provides robust targetry for the generation and study of high-repetitionrate ion beams using next-generation high-power laser systems,also enabling wider applications of laser-driven proton sources.

关键词： high-repetition-rate laser target laser-plasma acceleration proton generation tape-drive target

Evolution of Microalloyed Linepipe Steels With Particular Emphasis on the “Near Stoichiometry” Low Carbon,0.10 Percent Niobium “HTP” Concept

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journal of Iron and Steel research International 2011年第S1期18卷 652-657页

作者： gray j.Malcolm Microalloyed Steel Institute Inc. 5100 Westheimer Ste 540HoustonTX 77056 USA

Microalloyed linepipe steels were first introduced in 1959 at strength levels around 52-60 ksi [1] [2].The steels were generally strengthened by niobium or vanadium used *** strengths levels increased to X-70 in the early 1970’s niobium and vanadium were used in combination and controlled rolling was introduced on a broad *** strengths decrease tolerance for impurities and non-metallic inclusions which required improved steelmaking ***,carbon,and nitrogen were reduced and continuous casting was increasingly applied which required improved ladle refining and deoxidation ***-molybdenum steels were introduced by IPSCO in 1972 [3] and by Italsider in 1974 [4].Steels with higher niobium contents were also introduced in the early 1970’s but available steelmaking technologies limited the use of optimum niobium to carbon ratios,*** approaching *** the steels benefited from the effect of niobium in retarding austenite recrystallization at relatively high rolling temperatures and they developed attractive combinations of strength and toughness in old manufacturing facilities using simple (relaxed) rolling *** in the price of molybdenum and vanadium in the past decade and expanded application of API Grade X-80 linepipe,have led to more widespread use of niobium contents up to 0.11 percent,in combination with 0.02-0.03 percent carbon (near stoichiometry) thus maximizing the effects of solute niobium during rolling,in lowering transformation temperature,and thereby reducing reliance on other alloying,often expensive,*** history of these developments will be presented and applications of the concept will be summarized.

关键词： HTP Low Carbon,0.10 Percent Niobium Near Stoichiometry Evolution of Microalloyed Linepipe Steels With Particular Emphasis on the Concept

From bench to bedside： bipolar androgen therapy in a pilot clinical study

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Asian journal of Andrology 2015年第5期17卷 767-768页

作者： Qing Zhang Phillip j gray Department of Internal Medicine Singapore General Hospital Singapore Department of radiationOncology Massachusetts General Hospital HarvardMedical School Boston MA USA

Prostate cancer remains a leading cause of cancer death in Europe andthe United States and is an emerging problem in Asia despite significant improvements in available treatments over the last few decades. Androgen deprivation therapy （ADT） has been the core treatment of advance-staged disease since the discovery of prostate cancer＇s androgen dependence in 1941 by Huggins et al. Options for initial medical treatment include gonadotropin-releasing hormone analogues such as leuprolide （LHrH agonist） and degarelix （LHrH antagonist） and androgen receptor （Ar） binding agents such as bicalutamide. Although most patients will initially respond to either surgical or medical castration, there is almost always progression to castration-resistant prostate cancer （CrPC） necessitating treatment with more novel agents. However, even drugs such as abiraterone and enzalutamide, two next-generation agents used commonly in metastatic CrPC, have failed to demonstrate persistent efficacy in most patients.

关键词： advance-staged next-generation bicalutamide