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Fabrication of micrometre-sized periodic gratings in free-standing metallic foils for laser-plasma experiments

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High Power Laser Science and Engineering 2022年第1期10卷 17-31页

作者： C.C.Gheorghiu M.Cerchez E.Aktan R.Prasad F.Yilmaz N.Yilmaz D.Popa o.willi V.Leca Extreme Light Infrastructure-Nuclear Physics Horia Hulubei National Institute for Physics and Nuclear Engineering077125 MagureleRomania Institut fur Laser-und Plasmaphysik Heinrich-Heine-Universitat40225 DiisseldorfGermany

Engineered targets are expected to play a key role in future high-power laser experiments calling for joined, extensive knowledge in materials properties, engineering techniques and plasma physics. In this work, we propose a novel patterning procedure of self-supported 10 μm thick Au and Cu foils for obtaining micrometre-sized periodic gratings as targets for high-power laser applications. Accessible techniques were considered, by using cold rolling, electronbeam lithography and the Ar-ion milling process. The developed patterning procedure allows efficient control of the grating and foil surface on large area. Targets consisting of patterned regions of 450 μm × 450 μm, with 2 μm periodic gratings, were prepared on 25 mm × 25 mm Au and Cu free-standing foils, and preliminary investigations of the microtargets interacting with an ultrashort, relativistic laser pulse were performed. These test experiments demonstrated that,in certain conditions, the micro-gratings show enhanced laser energy absorption and higher efficiency in accelerating charge particle beams compared with planar thin foils of similar thickness.

关键词： laser driven plasmas on structured targets metallic foils micro-grating patterned targets

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卢瑟福·阿普耳顿实验室的X射线激光研究

国外激光 1989年第11期 13-20页

作者： o.willi D.Bassett 王世杰伦敦帝国科技学院

最近在中心激光装置上所进行的实验中,清楚地观察到复合碳等离子体中增益gl～4的182(?)自发辐射放大。直径7μm的碳丝,由火神Nd玻璃激光器系统照射。使用这种方案已在表面涂LiF的细碳丝靶上获得了更短的波长。初步的实验数据分析表明:... 详细信息

最近在中心激光装置上所进行的实验中,清楚地观察到复合碳等离子体中增益gl～4的182(?)自发辐射放大。直径7μm的碳丝,由火神Nd玻璃激光器系统照射。使用这种方案已在表面涂LiF的细碳丝靶上获得了更短的波长。初步的实验数据分析表明:已在氟的81(?)巴耳末α跃迁上获得增益。

关键词： X射线激光激光装置研究

Proton probing of laser-driven EM pulses travelling inhelical coils

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High Power Laser Science and Engineering 2017年第1期5卷 20-24页

作者： H.Ahmed S.Kar A.L.Giesecke D.Doria G.Nersisyan o.willi C.L.S.Lewis M.Borghesi Centre for Plasma Physics School of Mathematics and PhysicsQueen's University of BelfastBT7 INNUK Institut fiir Laser-und Plasmaphysik Heinrich-Heine-UniversitatDiisseldorfGermany

The ultrafast charge dynamics following the interaction of an ultra-intense laser pulse with a foil target leads to the launch of an ultra-short, intense electromagnetic(EM) pulse along a wire connected to the target. Due to the strong electric field(of the order of GV m^(-1)) associated to such laser-driven EM pulses, these can be exploited in a travelling-wave helical geometry for controlling and optimizing the parameters of laser accelerated proton beams. The propagation of the EM pulse along a helical path was studied by employing a proton probing technique. The pulse-carrying coil was probed along two orthogonal directions, transverse and parallel to the coil axis. The temporal profile of the pulse obtained from the transverse probing of the coil is in agreement with the previous measurements obtained in a planar geometry. The data obtained from the longitudinal probing of the coil shows a clear evidence of an energy dependent reduction of the proton beam divergence, which underpins the mechanism behind selective guiding of laser-driven ions by the helical coil targets.

关键词： acceleration EM pulse ion laser proton proton probing

ARCTURUS laser: a versatile high-contrast,high-power multi-beam laser system

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High Power Laser Science and Engineering 2019年第3期7卷 1-11页

作者： M.Cerchez R.Prasad B.Aurand A.L.Giesecke S.Spickermann S.Brauckmann E.Aktan M.Swantusch M.Toncian T.Toncian o.willi Institut für Laser und Plasmaphysik Heinrich-Heine-Universitat Dusseldorf40225 DusseldorfGermany Helmholtz-Zentrum Dresden-Rossendorf 01328 DresdenGermany

With the latest configuration,the Ti:Sa laser system ARCTURUS(Düsseldorf University,Germany)operates with a double-chirped pulse amplification(CPA)architecture delivering pulses with an energy of 7 J before compression in each of the two high-power *** the implementation of a plasma mirror system,the intrinsic laser contrast is enhanced up to 10^-12 on a time scale of hundreds of picoseconds,before the main *** laser system has been used in various configurations for advanced experiments and different studies have been carried out employing the high-power laser beams as a single,high-intensity interaction beam(I≈1020 W/cm^2),in dual-and multi-beam configurations or in a pump–probe arrangement.

关键词： Ti:Sa lasers multi-beam configuration high power laser pulses relativistic plasmas laser driven particle and radiation.sources

Highly-collimated, high-charge and broadband MeV electron beams produced by magnetizing solids irradiated by high-intensity lasers

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Matter and Radiation at Extremes 2019年第4期4卷 1-8页

作者： S.Bolaños J.Beard G.Revet S.N.Chen S.Pikuz E.Filippov M.Safronova M.Cerchez o.willi M.Starodubtsev J.Fuchs LULI—CNRS Ecole PolytechniqueCEA:Universite Paris-SaclayUPMC Univ Paris 06:Sorbonne UniversitesF-91128 Palaiseau CedexFrance LNCMI UPR 3228CNRS-UGA-UPS-INSA31400 ToulouseFrance Institute of Applied Physics 46 Ulyanov Street603950 Nizhny NovgorodRussian Federation ELI-NP “Horia Hulubei”National Institute for Physics and Nuclear Engineering30 Reactorului StreetRO-077125 Bucharest-MagureleRomania Joint Institute for High Temperatures RAS125412 MoscowRussian Federation National Research Nuclear University MEPhI 115409 MoscowRussian Federation Institute for Laser and Plasma Physics University of DusseldorfDusseldorfGermany

Laser irradiation of solid targets can drive short and high-charge relativistic electron bunches over micron-scale acceleration ***,for a long time,this technique was not considered a viable means of electron acceleration due to the large intrinsic divergence(∼50°half-angle)of the ***,a reduction in this divergence to 10°–20°half-angle has been obtained,using plasma-based magnetic fields or very high contrast laser pulses to extract the electrons into the *** we show that we can further improve the electron beam collimation,down to∼1.5°half-angle,of a high-charge(6 nC)beam,and in a highly reproducible manner,while using standard stand-alone 100 TW-class laser *** is obtained by embedding the laser-target interaction in an external,large-scale(cm),homogeneous,extremely stable,and high-strength(20 T)magnetic field that is independent of the *** upcoming multi-PW,high repetition-rate lasers,this technique opens the door to achieving even higher charges(>100 nC).

关键词： charge high acceleration

Stability analysis of a time-delayed Van der Pol–Helmholtz–Duffing oscillator in fractal space with a non-perturbative approach

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Communications in Theoretical Physics 2024年第4期76卷 22-31页

作者： Yusry o El-Dib Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt

The time-delayed fractal Van der Pol–Helmholtz–Duffing(VPHD)oscillator is the subject of this paper,which explores its mechanisms and highlights its stability *** time-delayed technologies are currently garnering significant attention,the focus of this research remains crucially relevant.A non-perturbative approach is employed to refine and set the stage for the system under *** innovative methodologies introduced yield an equivalent linear differential equation,mirroring the inherent nonlinearities of the ***,the incorporation of quadratic nonlinearity into the frequency formula represents a cutting-edge *** analytical solution's validity is corroborated using a numerical *** conditions are ascertained through the residual Galerkin ***,it is observed that the delay parameter,in the context of the fractal system,reverses its stabilizing influence,impacting both the amplitude of delayed velocity and the *** analytical solution's precision is underscored by its close alignment with numerical ***,the study reveals that fractal characteristics emulate damping *** its applicability across diverse nonlinear dynamical systems,this non-perturbative approach emerges as a promising avenue for future research.

关键词： Van der Pol-Helmholtz-Duffing oscillator fractal space time-delay non-perturbative approach stability analysis El-Dib's frequency formula

激光等离子体不稳定自聚焦细丝可能性的实验研究

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中国激光 1983年第Z1期 500-500页

作者：林尊琪 o.willi P.T.Rumsby R.G.Evans J.Szechi 中国科学院上海光学精密机械研究所英国卢瑟福-阿普尔顿实验室

作者曾提出冕区激光等离子体中光自聚焦细丝可能是大量的、不稳定的过程。它可能会影响激光的吸收和冕区多种非线性相互作用过程。这里我们首次报告倍频打靶（λ=0.53μm）后向散射ωo时间分辨谱呈现强烈时间和光谱调制的实验结果。调... 详细信息

作者曾提出冕区激光等离子体中光自聚焦细丝可能是大量的、不稳定的过程。它可能会影响激光的吸收和冕区多种非线性相互作用过程。这里我们首次报告倍频打靶（λ=0.53μm）后向散射ωo时间分辨谱呈现强烈时间和光谱调制的实验结果。调制的时间和光谱尺度分别约为10ps和3～5A。当激光靶面功率密度在1012W/cm2到5×1015W/cm2大范围内调整及靶原子序在大范围内变动的条件下都发现明显的调制现象。实验表明,光谱时间调制结构在靶面各取样点的空间相关性是很差的。这可能意

关键词：细丝激光等离子体谐波辐射

Making topological protein links using enzymatic reactions

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National Science Review 2024年第03期11卷 50-51页

作者： Roger Castells-Graells Todd o.Yeates Department of Chemistry and Biochemistry University of California UCLA-DoE Institute for Genomics and Proteomics

Proteins are exceedingly complex molecules though, at their heart, they are essentially linear polymers. Pull at their ends and one obtains an extended backbone. While that is true in most cases, some natural proteins... 详细信息

关键词： DESIGN

A synthetic microbial community used as a bioinoculant can overcome rice production constraints in acid soils

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Science China(Life Sciences) 2024年第5期67卷 1085-1086页

作者： Maureen o’Callaghan Shengjing Shi Resilient Agriculture Group AgResearchLincolnChristcurch 8140New Zealand

A customised synthetic microbial community(SynCom)composed of carefully selected rhizosphere-competent bacterial strains improved rice growth,yield and resistance to soil acidity and Al toxicity.

关键词： soil soils rhizosphere