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Irradiation uniformity at the Laser MegaJoule facility in the context of the shock ignition scheme

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High Power Laser Science and Engineering 2014年第2期2卷 1-12页

作者： Mauro Temporal Benoit Canaud Warren J. Garbett rafael ramis Stefan Weber Centre de Math'ematiques et de Leurs Applications ENS Cachan and CNRS 61 Av. du President Wilson Cachan Cedex France CEA DIF Arpajon Cedex France AWE plc Aldermaston Reading Berkshire United Kingdom ETSI Aeron'auticos Universidad Polit'ecnica de Madrid Madrid Spain ELI-Beamlines Institute of Physics Academy of Sciences of the Czech Republic Prague Czech Republic

The use of the Laser MegaJoule facility within the shock ignition scheme has been considered. In the first part of the study, one-dimensional hydrodynamic calculations were performed for an inertial confinement fusion capsule in the context of the shock ignition scheme providing the energy gain and an estimation of the increase of the peak power due to the reduction of the photon penetration expected during the high-intensity spike pulse. In the second part, we considered a Laser MegaJoule configuration consisting of 176 laser beams that have been grouped providing two different irradiation schemes. In this configuration the maximum available energy and power are 1.3 MJ and 440 TW. Optimization of the laser–capsule parameters that minimize the irradiation non-uniformity during the first few ns of the foot pulse has been performed. The calculations take into account the specific elliptical laser intensity profile provided at the Laser MegaJoule and the expected beam uncertainties. A significant improvement of the illumination uniformity provided by the polar direct drive technique has been demonstrated. Three-dimensional hydrodynamic calculations have been performed in order to analyse the magnitude of the azimuthal component of the irradiation that is neglected in twodimensional hydrodynamic simulations.

关键词： inertial confinement fusion shock ignition laser system

Simulations on the multi-shell target ignition driven by radiation pulse in Z-pinch dynamic hohlraum

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Chinese Physics B 2021年第11期30卷 411-418页

作者： Shi-Jia Chen Yan-Yun Ma Fu-Yuan Wu Xiao-Hu Yang Yun Yuan Ye Cui rafael ramis Department of Physics National University of Defense TechnologyChangsha 410073China IFSA Collaborative Innovation Center Shanghai Jiao Tong UniversityShanghai 200240China College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China Laboratory of Laser Plasmas School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China E.T.S.I.Aeronautica y del Espacio Universidad Politecnica de MadridSpain

We present the first simulation results of a multi-shell target ignition driven by Z-pinch dynamic hohlraum radiation *** radiation pulse is produced with a special Z-pinch dynamic hohlraum configuration,where the hohlraum is composed of a single metal liner,a low-Z plastic foam,and a high-Z metallic *** implosion dynamics of a hohlraum and a multi-shell target are investigated separately by the one-dimensional code *** the peak drive current is 50 MA,simulations suggest that an x-ray pulse with nearly constant radiation temperature(-310 eV)and a duration about 9 ns can be obtained.A small multi-shell target with a radius of 1.35 mm driven by this radiation pulse is able to achieve volumetric ignition with an energy gain(G)about 6.19,where G is the ratio of the yield to the absorbed *** this research,we better understand the effects of non-uniformities and hydrodynamics instabilities in Z-pinch dynamic hohlraum.

关键词： Z-pinch dynamic hohlraum radiation pulse volumetric ignition

Optimal laser intensity profiles for a uniform target illumination in direct-drive inertial confinement fusion

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High Power Laser Science and Engineering 2014年第4期2卷 62-67页

作者： Mauro Temporal Benoit Canaud Warren J.Garbett rafael ramis Centre de Mathématiques et de Leurs Applications ENS Cachan and CNRS 61 Av.du President WilsonF-94235 Cachan Cedex France CEA DIF F-91297 Arpajon Cedex France AWE plc Aldermaston ReadingBerkshire RG7 4PR United Kingdom ETSI Aeronuticos Universidad Polit'ecnica de Madrid28040 Madrid Spain

A numerical method providing the optimal laser intensity profiles for a direct-drive inertial confinement fusion scheme has been developed. The method provides an alternative approach to phase-space optimization studies, which can prove computationally expensive. The method applies to a generic irradiation configuration characterized by an arbitrary number NBof laser beams provided that they irradiate the whole target surface, and thus goes beyond previous analyses limited to symmetric configurations. The calculated laser intensity profiles optimize the illumination of a spherical *** paper focuses on description of the method, which uses two steps: first, the target irradiation is calculated for initial trial laser intensities, and then in a second step the optimal laser intensities are obtained by correcting the trial intensities using the calculated illumination. A limited number of example applications to direct drive on the Laser Mega Joule(LMJ) are described.

关键词： direct drive inertial confinement fusion laser system

Z箍缩动态黑腔形成过程MULTI程序一维数值模拟

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物理学报 2017年第21期66卷 305-312页

作者：吴福源褚衍运叶繁李正宏杨建伦 rafael ramis 王真祁建敏周林梁川中国工程物理研究院核物理与化学研究所绵阳621900 西班牙马德里理工大学航空航天学院马德里28040

Z箍缩动态黑腔能够高效地将Z箍缩丝阵等离子体动能转换为黑腔辐射能,为驱动惯性约束靶丸聚变提供高品质的X射线辐射场.利用一维双温多群辐射磁流体力学程序MULTI-IFE,研究了"聚龙一号"装置驱动电流条件下的Z箍缩动态黑腔形成基本物理过... 详细信息

Z箍缩动态黑腔能够高效地将Z箍缩丝阵等离子体动能转换为黑腔辐射能,为驱动惯性约束靶丸聚变提供高品质的X射线辐射场.利用一维双温多群辐射磁流体力学程序MULTI-IFE,研究了"聚龙一号"装置驱动电流条件下的Z箍缩动态黑腔形成基本物理过程.数值模拟结果表明,在动态黑腔形成过程中,辐射热波的传播速度比冲击波的传播速度更快,比冲击波更早到达泡沫中心,使中心区域的泡沫在冲击波到达前就已具有较高的辐射温度.对于"聚龙一号"装置动态黑腔实验0180发次采用的负载参数,辐射热波和冲击波在泡沫中的传播速度分别约为36.1 cm/μs和17.6 cm/μs,黑腔辐射温度在黑腔形成初期约80 eV,在冲击波到达泡沫中心前可达100 eV以上,丝阵等离子体外表面发射的X射线能量集中在1000 eV以下.本文给出了程序采用的计算模型、美国"土星"装置丝阵内爆计算结果和"聚龙一号"装置动态黑腔实验0180发次模拟结果.

关键词： Z箍缩动态黑腔辐射磁流体力学冲击波

Numerical studies on the radiation uniformity of Z-pinch dynamic hohlraum

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Matter and Radiation at Extremes 2018年第5期3卷 248-255页

作者： Fuyuan Wu Yanyun Chu rafael ramis Zhenghong Li Yanyun Ma Jianlun Yang Zhen Wang Fan Ye Zhanchang Huang Jianmin Qi Lin Zhou Chuan Liang Shijia Chen Zheyi Ge Xiaohu Yang Shangwu Wang College of Liberal Arts and Sciences National University of Defense TechnologyChangsha410073China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang621900China E.T.S.I.Aeronauticos y del Espacio Universidad Politecnica de MadridMadrid28040Spain IFSA Collaborative Innovation Center Shanghai Jiao Tong UniveristyShanghai200240China

Radiation uniformity is important for Z-pinch dynamic hohlraum driven fusion. In order to understand the radiation uniformity of Z-pinchdynamic hohlraum, the code MULTI-2D with a new developed magnetic field package is employed to investigate the related physical processeson Julong-I facility with drive current about 7e8 MA. Numerical simulations suggest that Z-pinch dynamic hohlraum with radiation temperaturemore than 100 eV can be created on Julong-I facility. Although some X-rays can escape out of the hohlraum from Z-pinch plasma and electrodes, the radiation field near the foam center is quite uniform after a transition time. For the load parameters used in this paper, the transitiontime for the thermal wave transports from r = 1 mm to r = 0 mm is about 2.0 ns. Implosion of a testing pellet driven by cylindrical dynamichohlraum shows that symmetrical implosion is hard to achieve due to the relatively slow propagation speed of thermal wave and the compressionof cylindrical shock in the foam. With the help of quasi-spherical implosion, the hohlraum radiation uniformity and corresponding pelletimplosion symmetry can be significantly improved thanks to the shape modulation of thermal wave front and shock wave front.

关键词： Z-pinch Dynamic hohlraum Radiation uniformity Shock wave Thermal wave

高密度等离子体喷流高速对撞的二维辐射流体模拟研究

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物理学报 2022年第22期71卷 192-200页

作者：杨孟奇吴福源陈致博张翼翔陈一张晋川陈致真方志凡 rafael ramis 张杰上海交通大学物理与天文学院激光等离子体教育部重点实验室上海200240 上海交通大学致远学院上海200240 上海交通大学IFSA协同创新中心上海200240 西班牙马德里理工大学航空航天学院马德里28040

等离子体喷流对撞是天体物理和激光等离子体物理中常见的流体力学现象.构建对撞等离子体状态和喷流初始条件的流体定标关系,对于相关实验的物理设计和数据分析具有重要意义.本文采用最新升级的二维自由拉格朗日辐射流体模拟程序MULTI-2D... 详细信息

等离子体喷流对撞是天体物理和激光等离子体物理中常见的流体力学现象.构建对撞等离子体状态和喷流初始条件的流体定标关系,对于相关实验的物理设计和数据分析具有重要意义.本文采用最新升级的二维自由拉格朗日辐射流体模拟程序MULTI-2D,研究了高速(≥100 km/s)、高密度(≥10 g/cm^(3))条件下的喷流对撞过程.基于不同条件下等离子体喷流高速对撞过程的模拟数据,通过机器学习中的贝叶斯推断方法构建了描述等离子体喷流对撞过程的流体定标规律.研究结果表明:锥形等离子体喷流对撞易于形成等容分布的高密度等离子体;提高喷流的初始密度和速度,有利于提高对撞等离子体的密度和温度;提高喷流的初始温度,有利于提高对撞后的温度,但会降低对撞后的等离子体密度.当等离子体喷流的初始密度、温度和速度分别设定为15 g/cm^(3), 30 eV和300 km/s时,对撞后的等离子体密度可以达到300 g/cm^(3)以上,这对于双锥对撞点火方案中的快电子加热过程非常重要.

关键词：等离子体喷流机器学习流体定标律双锥对撞点火

Analysis of three-dimensional effects in laser driven thin-shell capsule implosions

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Matter and Radiation at Extremes 2019年第5期4卷 55-66页

作者： rafael ramis Benoit Canaud Mauro Temporal Warren J.Garbett Franck Philippe E.T.S.I.Aeronauticay del Espacio Universidad Politecnica de MadridP.Cardenal Cisneros 3E-28040MadridSpain CEA DAMDIF91297 Arpajon CedexFrance CentredeMathematiques etdeLeurs Applications ENSCachanandCNRS61 Av.duPresident Wilson94235CachanCedexFrance AWE plc AldermastonReadingBerkshire RG74PRUnited Kingdom

Three-dimensional(3D)hydrodynamic numerical simulations of laser driven thin-shell gas-filled microballoons have been carried out using the computer code MULTI-3D[ramis et al.,*** 21,082710(2014)].The studied configuration corresponds to experiments carried at the ORION laser facility[Hopps et al.,Plasma *** Fusion 57,064002(2015)].The MULTI-3D code solves single-temperature hydrodynamics,electron heat transport,and 3D ray tracing with inverse bremsstrahlung absorption on unstructured Lagrangian *** emphasis has been placed on the genuine 3D effects that are inaccessible to calculations using simplified 1D or 2D *** include the consequences of(i)a finite number of laser beams(10 in the experimental campaign),(ii)intensity irregularities in the beam crosssectional profiles,(iii)laser beam misalignments,and(iv)power imbalance between *** consequences of these imperfections have been quantified by post-processing the numerical results in terms of capsule nonuniformities(synthetic emission and absorption images)and implosion efficiency(convergence ratio and neutron yield).Statistical analysis of these outcomes allows determination of the laser tolerances that guarantee a given level of target performance.

关键词： consequences absorption dimensional