S. Tan, Q. Wang, Y. Chen, W. B. Yao, C. Z. Xiao, J. F. Myatt
Rescattering of stimulated Raman side scattering (SRSS) is observed for the first time via two-dimensional (2D) particle-in-cell (PIC) simulations. We construct a theoretical model for the rescattering process, which can predict the region of occurrence of mth-order SRSS and estimate its threshold. The rescattering process is identified by the 2D PIC simulations under typical conditions of a direct-drive inertial confinement fusion scheme. Hot electrons produced by second-order SRSS propagate nearly perpendicular to the density gradient and gain nearly the same energy as in first-order SRSS, but there is no cascade acceleration to produce superhot electrons. Parametric studies for a wide range of ignition conditions show that SRSS and associated rescatterings are robust and important processes in inertial confinement fusion.
{"title":"Rescattering of stimulated Raman side scattering in nonuniform plasmas","authors":"S. Tan, Q. Wang, Y. Chen, W. B. Yao, C. Z. Xiao, J. F. Myatt","doi":"10.1063/5.0206740","DOIUrl":"https://doi.org/10.1063/5.0206740","url":null,"abstract":"Rescattering of stimulated Raman side scattering (SRSS) is observed for the first time via two-dimensional (2D) particle-in-cell (PIC) simulations. We construct a theoretical model for the rescattering process, which can predict the region of occurrence of mth-order SRSS and estimate its threshold. The rescattering process is identified by the 2D PIC simulations under typical conditions of a direct-drive inertial confinement fusion scheme. Hot electrons produced by second-order SRSS propagate nearly perpendicular to the density gradient and gain nearly the same energy as in first-order SRSS, but there is no cascade acceleration to produce superhot electrons. Parametric studies for a wide range of ignition conditions show that SRSS and associated rescatterings are robust and important processes in inertial confinement fusion.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tobias Dornheim, Sebastian Schwalbe, Panagiotis Tolias, Maximilian P. Böhme, Zhandos A. Moldabekov, Jan Vorberger
We present quasi-exact ab initio path integral Monte Carlo (PIMC) results for the partial static density responses and local field factors of hydrogen in the warm dense matter regime, from solid density conditions to the strongly compressed case. The full dynamic treatment of electrons and protons on the same footing allows us to rigorously quantify both electronic and ionic exchange–correlation effects in the system, and to compare the results with those of earlier incomplete models such as the archetypal uniform electron gas or electrons in a fixed ion snapshot potential that do not take into account the interplay between the two constituents. The full electronic density response is highly sensitive to electronic localization around the ions, and our results constitute unambiguous predictions for upcoming X-ray Thomson scattering experiments with hydrogen jets and fusion plasmas. All PIMC results are made freely available and can be used directly for a gamut of applications, including inertial confinement fusion calculations and the modeling of dense astrophysical objects. Moreover, they constitute invaluable benchmark data for approximate but computationally less demanding approaches such as density functional theory or PIMC within the fixed-node approximation.
我们展示了从固体密度条件到强压缩情况下，氢在暖致密物质体系中的部分静态密度响应和局部场因子的准精确ab initio路径积分蒙特卡洛（PIMC）结果。在同一基础上对电子和质子进行全动态处理，使我们能够严格量化系统中的电子和离子交换相关效应，并将结果与早期的不完整模型（如典型的均匀电子气体或固定离子快照电势中的电子）进行比较，这些模型没有考虑两种成分之间的相互作用。全电子密度响应对离子周围的电子定位高度敏感，我们的结果为即将进行的氢喷流和聚变等离子体 X 射线汤姆逊散射实验提供了明确的预测。所有 PIMC 结果均免费提供，可直接用于各种应用，包括惯性约束聚变计算和高密度天体物理建模。此外，它们还是近似但计算要求较低的方法（如密度泛函理论或固定节点近似中的 PIMC）的宝贵基准数据。
{"title":"Ab initio density response and local field factor of warm dense hydrogen","authors":"Tobias Dornheim, Sebastian Schwalbe, Panagiotis Tolias, Maximilian P. Böhme, Zhandos A. Moldabekov, Jan Vorberger","doi":"10.1063/5.0211407","DOIUrl":"https://doi.org/10.1063/5.0211407","url":null,"abstract":"We present quasi-exact ab initio path integral Monte Carlo (PIMC) results for the partial static density responses and local field factors of hydrogen in the warm dense matter regime, from solid density conditions to the strongly compressed case. The full dynamic treatment of electrons and protons on the same footing allows us to rigorously quantify both electronic and ionic exchange–correlation effects in the system, and to compare the results with those of earlier incomplete models such as the archetypal uniform electron gas or electrons in a fixed ion snapshot potential that do not take into account the interplay between the two constituents. The full electronic density response is highly sensitive to electronic localization around the ions, and our results constitute unambiguous predictions for upcoming X-ray Thomson scattering experiments with hydrogen jets and fusion plasmas. All PIMC results are made freely available and can be used directly for a gamut of applications, including inertial confinement fusion calculations and the modeling of dense astrophysical objects. Moreover, they constitute invaluable benchmark data for approximate but computationally less demanding approaches such as density functional theory or PIMC within the fixed-node approximation.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141779515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jing Yang, Xinxin Wang, Liang Xu, Qiannan Wang, Yi Sun, Jiangtao Li, Lin Zhang, Yinghua Li, Yuying Yu, Pei Wang, Qiang Wu, Jianbo Hu
We present a novel method for investigating laser-driven dynamic fragmentation in tin using in situ X-ray diffraction. Our experimental results demonstrate the feasibility of the method for simultaneously identifying the phase and temperature of fragments through analysis of the diffraction pattern. Surprisingly, we observe a deviation from the widely accepted isentropic release assumption, with the temperature of the fragments being found to be more than 100 K higher than expected, owing to the release of plastic work during dynamic fragmentation. Our findings are further verified through extensive large-scale molecular dynamics simulations, in which strain energies are found to be transferred into thermal energies during the nucleation and growth of voids, leading to an increase in temperature. Our findings thus provide crucial insights into the impact-driven dynamic fragmentation phenomenon and reveal the significant influence of plastic work on material response during shock release.
我们提出了一种利用原位 X 射线衍射研究锡中激光驱动动态碎裂的新方法。我们的实验结果表明，通过分析衍射图样同时确定碎片的相位和温度的方法是可行的。令人惊讶的是，我们观察到与广泛接受的等熵释放假设存在偏差，由于在动态破碎过程中释放了塑性功，碎片的温度比预期高出 100 K 以上。我们的发现通过大规模分子动力学模拟得到进一步验证，在模拟中发现应变能在空洞的成核和生长过程中转移为热能，从而导致温度升高。因此，我们的研究结果为了解冲击驱动的动态碎裂现象提供了重要依据，并揭示了塑性功对冲击释放过程中材料响应的重要影响。
{"title":"Direct visualization of laser-driven dynamic fragmentation in tin by in situ x-ray diffraction","authors":"Jing Yang, Xinxin Wang, Liang Xu, Qiannan Wang, Yi Sun, Jiangtao Li, Lin Zhang, Yinghua Li, Yuying Yu, Pei Wang, Qiang Wu, Jianbo Hu","doi":"10.1063/5.0200242","DOIUrl":"https://doi.org/10.1063/5.0200242","url":null,"abstract":"We present a novel method for investigating laser-driven dynamic fragmentation in tin using in situ X-ray diffraction. Our experimental results demonstrate the feasibility of the method for simultaneously identifying the phase and temperature of fragments through analysis of the diffraction pattern. Surprisingly, we observe a deviation from the widely accepted isentropic release assumption, with the temperature of the fragments being found to be more than 100 K higher than expected, owing to the release of plastic work during dynamic fragmentation. Our findings are further verified through extensive large-scale molecular dynamics simulations, in which strain energies are found to be transferred into thermal energies during the nucleation and growth of voids, leading to an increase in temperature. Our findings thus provide crucial insights into the impact-driven dynamic fragmentation phenomenon and reveal the significant influence of plastic work on material response during shock release.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141779516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ke Feng, Kangnan Jiang, Runshu Hu, Shixia Luan, Wentao Wang, Ruxin Li
In this paper, promising but simple schemes are investigated to enhance the micro-bunching of relativistic electron beams for coherent harmonic generation (CHG) by using phase merging effects. In contrast to the standard CHG scheme, two specially designed dispersion sections (DSs) are adopted with the DS-modulator–DS configuration. The phase space of the e beam is appropriately coupled in the first DS, and the electrons within one seed wavelength can merge to the same phase with a matched second DS. Micro-bunching of the e beam can thus be enhanced by a large margin with much higher-harmonic components. Taking e beams from laser wakefield accelerators (LWFAs) as an example, start-to-end simulations are performed to show the effectiveness and robustness of the proposed schemes with several configurations. The beam current can be optimized to several tens to hundreds of kiloamperes, and the radiation power reaches hundreds of megawatts in the extreme ultraviolet regime within a 3.5 m-long beamline. The proposed schemes offer new opportunities for future compact free-electron lasers driven by LWFAs and provides prospects for truly compact and widely applicable systems.
{"title":"Bunching enhancement for coherent harmonic generation by using phase merging effects","authors":"Ke Feng, Kangnan Jiang, Runshu Hu, Shixia Luan, Wentao Wang, Ruxin Li","doi":"10.1063/5.0191508","DOIUrl":"https://doi.org/10.1063/5.0191508","url":null,"abstract":"In this paper, promising but simple schemes are investigated to enhance the micro-bunching of relativistic electron beams for coherent harmonic generation (CHG) by using phase merging effects. In contrast to the standard CHG scheme, two specially designed dispersion sections (DSs) are adopted with the DS-modulator–DS configuration. The phase space of the e beam is appropriately coupled in the first DS, and the electrons within one seed wavelength can merge to the same phase with a matched second DS. Micro-bunching of the e beam can thus be enhanced by a large margin with much higher-harmonic components. Taking e beams from laser wakefield accelerators (LWFAs) as an example, start-to-end simulations are performed to show the effectiveness and robustness of the proposed schemes with several configurations. The beam current can be optimized to several tens to hundreds of kiloamperes, and the radiation power reaches hundreds of megawatts in the extreme ultraviolet regime within a 3.5 m-long beamline. The proposed schemes offer new opportunities for future compact free-electron lasers driven by LWFAs and provides prospects for truly compact and widely applicable systems.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141570498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhiyu Lei, Hanghang Ma, Xiaobo Zhang, Lin Yu, Yihang Zhang, Yutong Li, Suming Weng, Min Chen, Jie Zhang, Zhengming Sheng
A scheme for a quasi-monoenergetic high-flux neutron source with femtosecond duration and highly anisotropic angular distribution is proposed. This scheme is based on bulk acceleration of deuteron ions in an optical trap or density grating formed by two counter-propagating laser pulses at an intensity of ∼1016W/cm2 in a near-critical-density plasma. The deuterons are first pre-accelerated to an energy of tens of keV in the ambipolar fields formed in the optical trap. Their energy is boosted to the MeV level by another one or two laser pulses at an intensity of ∼1020W/cm2, enabling fusion reactions to be triggered with high efficiency. In contrast to previously proposed pitcher–catcher configurations, our scheme can provide spatially periodic acceleration structures and effective collisions between deuterons inside the whole target volume. Subsequently, neutrons are generated directly inside the optical trap. Our simulations show that neutron pulses with energy 2–8 MeV, yield 1018–1019n/s, and total number 106–107 in a duration ∼400 fs can be obtained with a 25 μm target. Moreover, the neutron pulses exhibit unique angularly dependent energy spectra and flux distributions, predominantly along the axis of the energy-boosting lasers. Such microsize femtosecond neutron pulses may find many applications, such as high-resolution fast neutron imaging and nuclear physics research.
{"title":"Compact ultrafast neutron sources via bulk acceleration of deuteron ions in an optical trap","authors":"Zhiyu Lei, Hanghang Ma, Xiaobo Zhang, Lin Yu, Yihang Zhang, Yutong Li, Suming Weng, Min Chen, Jie Zhang, Zhengming Sheng","doi":"10.1063/5.0208901","DOIUrl":"https://doi.org/10.1063/5.0208901","url":null,"abstract":"A scheme for a quasi-monoenergetic high-flux neutron source with femtosecond duration and highly anisotropic angular distribution is proposed. This scheme is based on bulk acceleration of deuteron ions in an optical trap or density grating formed by two counter-propagating laser pulses at an intensity of ∼1016W/cm2 in a near-critical-density plasma. The deuterons are first pre-accelerated to an energy of tens of keV in the ambipolar fields formed in the optical trap. Their energy is boosted to the MeV level by another one or two laser pulses at an intensity of ∼1020W/cm2, enabling fusion reactions to be triggered with high efficiency. In contrast to previously proposed pitcher–catcher configurations, our scheme can provide spatially periodic acceleration structures and effective collisions between deuterons inside the whole target volume. Subsequently, neutrons are generated directly inside the optical trap. Our simulations show that neutron pulses with energy 2–8 MeV, yield 1018–1019n/s, and total number 106–107 in a duration ∼400 fs can be obtained with a 25 μm target. Moreover, the neutron pulses exhibit unique angularly dependent energy spectra and flux distributions, predominantly along the axis of the energy-boosting lasers. Such microsize femtosecond neutron pulses may find many applications, such as high-resolution fast neutron imaging and nuclear physics research.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141570499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is of substantial scientific significance and practical value to reveal and understand the multiscale mechanical properties and intrinsic mechanisms of medium-entropy alloys (MEAs) under high strain rates and pressures. In this study, the mechanical responses and deformation mechanisms of an equiatomic CoCrNi MEA are investigated utilizing magnetically driven ramp wave compression (RWC) with a strain rate of 105 s−1. The CoCrNi MEA demonstrates excellent dynamic mechanical responses and yield strength under RWC compared with other advanced materials. Multiscale characterizations reveal that grain refinement and abundant micromechanisms, including dislocation slip, stacking faults, nanotwin network, and Lomer–Cottrell locks, collectively contribute to its excellent performance during RWC. Furthermore, dense deformation twins and shear bands intersect, forming a weave-like microstructure that can disperse deformation and enhance plasticity. On the basis of these observations, we develop a modified crystal plasticity model with coupled dislocation and twinning mechanisms, providing a relatively accurate quantitative description of the multiscale behavior under RWC. The results of simulations indicate that the activation of multilevel microstructures in CoCrNi MEA is primarily attributable to stress inhomogeneities and localized strain during RWC. Our research offers valuable insights into the dynamic mechanical responses of CoCrNi MEA, positioning it as a promising material for use under extreme dynamic conditions.
揭示和了解中熵合金（MEA）在高应变率和压力下的多尺度机械性能和内在机制具有重要的科学意义和实用价值。在本研究中，利用应变速率为 105 s-1 的磁驱动斜波压缩（RWC）研究了等原子 CoCrNi MEA 的机械响应和变形机制。与其他先进材料相比，钴铬镍 MEA 在 RWC 条件下表现出优异的动态机械响应和屈服强度。多尺度表征显示，晶粒细化和丰富的微观机制（包括位错滑移、堆叠断层、纳米孪晶网络和 Lomer-Cottrell 锁）共同促成了其在 RWC 期间的优异性能。此外，致密的变形孪晶与剪切带相交，形成了可分散变形并增强塑性的编织状微结构。在这些观察结果的基础上，我们建立了一个具有位错和孪晶耦合机制的修正晶体塑性模型，对 RWC 下的多尺度行为进行了相对准确的定量描述。模拟结果表明，CoCrNi MEA 中多级微结构的激活主要归因于 RWC 过程中的应力不均匀性和局部应变。我们的研究为了解钴铬镍 MEA 的动态机械响应提供了宝贵的见解，使其成为一种有望在极端动态条件下使用的材料。
{"title":"Mechanical responses and crystal plasticity model of CoCrNi medium-entropy alloy under ramp wave compression","authors":"Jinlei Dong, Xuping Zhang, Guiji Wang, Xianqian Wu, Binqiang Luo, Xuemiao Chen, Fuli Tan, Jianheng Zhao, Chengwei Sun","doi":"10.1063/5.0206773","DOIUrl":"https://doi.org/10.1063/5.0206773","url":null,"abstract":"It is of substantial scientific significance and practical value to reveal and understand the multiscale mechanical properties and intrinsic mechanisms of medium-entropy alloys (MEAs) under high strain rates and pressures. In this study, the mechanical responses and deformation mechanisms of an equiatomic CoCrNi MEA are investigated utilizing magnetically driven ramp wave compression (RWC) with a strain rate of 105 s−1. The CoCrNi MEA demonstrates excellent dynamic mechanical responses and yield strength under RWC compared with other advanced materials. Multiscale characterizations reveal that grain refinement and abundant micromechanisms, including dislocation slip, stacking faults, nanotwin network, and Lomer–Cottrell locks, collectively contribute to its excellent performance during RWC. Furthermore, dense deformation twins and shear bands intersect, forming a weave-like microstructure that can disperse deformation and enhance plasticity. On the basis of these observations, we develop a modified crystal plasticity model with coupled dislocation and twinning mechanisms, providing a relatively accurate quantitative description of the multiscale behavior under RWC. The results of simulations indicate that the activation of multilevel microstructures in CoCrNi MEA is primarily attributable to stress inhomogeneities and localized strain during RWC. Our research offers valuable insights into the dynamic mechanical responses of CoCrNi MEA, positioning it as a promising material for use under extreme dynamic conditions.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The achievement of ignition at the National Ignition Facility (NIF) has prompted a global wave of further research on inertial fusion energy (IFE). However, IFE requires a target gain G of 30–100, and it is hard to achieve fusion at such high gain with the energy, configuration, and technical approach of the NIF. Here, we present a conceptual design for a next-generation laser driver that is applicable to multiple laser fusion schemes and provides 10 MJ, 2–3 PW at 3ω (or 2ω, in which case the energy and power can be higher), and one shot per 30 min, with the aim of achieving G > 30. It is also efficient, compact, and low in cost, and it has low susceptibility to laser–plasma instabilities.
美国国家点火装置（NIF）实现点火后，全球掀起了进一步研究惯性聚变能（IFE）的热潮。然而，惯性聚变能要求目标增益 G 在 30-100 之间，而 NIF 的能量、配置和技术方法很难实现如此高增益的聚变。在这里，我们提出了下一代激光驱动器的概念设计，它适用于多种激光聚变方案，在3ω（或2ω，在这种情况下，能量和功率可以更高）时提供10兆焦耳、2-3 PW，每30分钟发射一次，目标是实现G > 30。它还具有效率高、结构紧凑和成本低的特点，而且对激光等离子体不稳定性的敏感性较低。
{"title":"Driver at 10 MJ and 1 shot/30 min for inertial confinement fusion at high gain: Efficient, compact, low-cost, low laser–plasma instabilities, beam color selectable from 2ω/3ω/4ω, applicable to multiple laser fusion schemes","authors":"Zhan Sui, Ke Lan","doi":"10.1063/5.0216435","DOIUrl":"https://doi.org/10.1063/5.0216435","url":null,"abstract":"The achievement of ignition at the National Ignition Facility (NIF) has prompted a global wave of further research on inertial fusion energy (IFE). However, IFE requires a target gain G of 30–100, and it is hard to achieve fusion at such high gain with the energy, configuration, and technical approach of the NIF. Here, we present a conceptual design for a next-generation laser driver that is applicable to multiple laser fusion schemes and provides 10 MJ, 2–3 PW at 3ω (or 2ω, in which case the energy and power can be higher), and one shot per 30 min, with the aim of achieving G > 30. It is also efficient, compact, and low in cost, and it has low susceptibility to laser–plasma instabilities.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Leonard Wegert, Stephan Schreiner, Constantin Rauch, Bruno Albertazzi, Paulina Bleuel, Eric Fröjdh, Michel Koenig, Veronika Ludwig, Artem S. Martynenko, Pascal Meyer, Aldo Mozzanica, Michael Müller, Paul Neumayer, Markus Schneider, Angelos Triantafyllidis, Bernhard Zielbauer, Gisela Anton, Thilo Michel, Stefan Funk
Single-shot X-ray phase-contrast imaging is used to take high-resolution images of laser-driven strong shock waves. Employing a two-grating Talbot interferometer, we successfully acquire standard absorption, differential phase-contrast, and dark-field images of the shocked target. Good agreement is demonstrated between experimental data and the results of two-dimensional radiation hydrodynamics simulations of the laser–plasma interaction. The main sources of image noise are identified through a thorough assessment of the interferometer’s performance. The acquired images demonstrate that grating-based phase-contrast imaging is a powerful diagnostic tool for high-energy-density science. In addition, we make a novel attempt at using the dark-field image as a signal modality of Talbot interferometry to identify the microstructure of a foam target.
单次 X 射线相位对比成像用于拍摄激光驱动的强冲击波的高分辨率图像。利用双光栅塔尔博特干涉仪，我们成功地获取了冲击目标的标准吸收、差分相位对比和暗场图像。实验数据与激光-等离子体相互作用的二维辐射流体力学模拟结果之间呈现出良好的一致性。通过对干涉仪性能的全面评估，确定了图像噪声的主要来源。获得的图像表明，基于光栅的相位对比成像是高能量密度科学的强大诊断工具。此外，我们还进行了一次新的尝试，利用暗场图像作为塔尔博特干涉仪的信号模式来识别泡沫目标的微观结构。
{"title":"Demonstrating grating-based phase-contrast imaging of laser-driven shock waves","authors":"Leonard Wegert, Stephan Schreiner, Constantin Rauch, Bruno Albertazzi, Paulina Bleuel, Eric Fröjdh, Michel Koenig, Veronika Ludwig, Artem S. Martynenko, Pascal Meyer, Aldo Mozzanica, Michael Müller, Paul Neumayer, Markus Schneider, Angelos Triantafyllidis, Bernhard Zielbauer, Gisela Anton, Thilo Michel, Stefan Funk","doi":"10.1063/5.0200440","DOIUrl":"https://doi.org/10.1063/5.0200440","url":null,"abstract":"Single-shot X-ray phase-contrast imaging is used to take high-resolution images of laser-driven strong shock waves. Employing a two-grating Talbot interferometer, we successfully acquire standard absorption, differential phase-contrast, and dark-field images of the shocked target. Good agreement is demonstrated between experimental data and the results of two-dimensional radiation hydrodynamics simulations of the laser–plasma interaction. The main sources of image noise are identified through a thorough assessment of the interferometer’s performance. The acquired images demonstrate that grating-based phase-contrast imaging is a powerful diagnostic tool for high-energy-density science. In addition, we make a novel attempt at using the dark-field image as a signal modality of Talbot interferometry to identify the microstructure of a foam target.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A generalized kinetic model of atomic level populations in an optically dense plasma excited by laser pulses of arbitrary duration is formulated and studied. This model is based on a nonstationary expression for the probability of excitation of an atomic transition and takes into account the effects of laser pulse penetration into an optically dense medium. A universal formula for the excitation probability as a function of time and propagation length is derived and applied to the case of a Lorentzian spectral profile of an atomic transition excited by a laser pulse with a Gaussian envelope. The features of nonstationary excitation probabilities are presented for different optical depths of the plasma, laser pulse durations, and carrier frequencies. The formulas derived here will be useful for the description of atomic populations excited by laser pulses under realistic conditions of dense plasmas.
{"title":"Kinetics of dense plasma in the field of short laser pulses: A generalized approach","authors":"V. Astapenko, V. Lisitsa","doi":"10.1063/5.0210407","DOIUrl":"https://doi.org/10.1063/5.0210407","url":null,"abstract":"A generalized kinetic model of atomic level populations in an optically dense plasma excited by laser pulses of arbitrary duration is formulated and studied. This model is based on a nonstationary expression for the probability of excitation of an atomic transition and takes into account the effects of laser pulse penetration into an optically dense medium. A universal formula for the excitation probability as a function of time and propagation length is derived and applied to the case of a Lorentzian spectral profile of an atomic transition excited by a laser pulse with a Gaussian envelope. The features of nonstationary excitation probabilities are presented for different optical depths of the plasma, laser pulse durations, and carrier frequencies. The formulas derived here will be useful for the description of atomic populations excited by laser pulses under realistic conditions of dense plasmas.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141344177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Lütgert, P. Hesselbach, M. Schörner, V. Bagnoud, R. Belikov, P. Drechsel, B. Heuser, O. Humphries, P. Katrík, B. Lindqvist, C. Qu, R. Redmer, D. Riley, G. Schaumann, S. Schumacher, A. Tauschwitz, D. Varentsov, K. Weyrich, X. Yu, B. Zielbauer, Zs. Major, P. Neumayer, D. Kraus
We present in situ measurements of spectrally resolved X-ray scattering and X-ray diffraction from monocrystalline diamond samples heated with an intense pulse of heavy ions. In this way, we determine the samples’ heating dynamics and their microscopic and macroscopic structural integrity over a timespan of several microseconds. Connecting the ratio of elastic to inelastic scattering with state-of-the-art density functional theory molecular dynamics simulations allows the inference of average temperatures around 1300 K, in agreement with predictions from stopping power calculations. The simultaneous diffraction measurements show no hints of any volumetric graphitization of the material, but do indicate the onset of fracture in the diamond sample. Our experiments pave the way for future studies at the Facility for Antiproton and Ion Research, where a substantially increased intensity of the heavy ion beam will be available.
我们展示了用强脉冲重离子加热单晶金刚石样品所产生的光谱分辨 X 射线散射和 X 射线衍射的现场测量结果。通过这种方法，我们确定了样品在几微秒时间跨度内的加热动态及其微观和宏观结构的完整性。将弹性散射与非弹性散射的比率与最先进的密度泛函理论分子动力学模拟联系起来，可以推断出 1300 K 左右的平均温度，这与停止功率计算的预测结果一致。同时进行的衍射测量没有显示出任何材料体积石墨化的迹象，但确实显示出金刚石样品开始断裂。我们的实验为今后在反质子和离子研究设施（Facility for Antiproton and Ion Research）进行研究铺平了道路，该设施的重离子束强度将大幅提高。
{"title":"Temperature and structure measurements of heavy-ion-heated diamond using in situ X-ray diagnostics","authors":"J. Lütgert, P. Hesselbach, M. Schörner, V. Bagnoud, R. Belikov, P. Drechsel, B. Heuser, O. Humphries, P. Katrík, B. Lindqvist, C. Qu, R. Redmer, D. Riley, G. Schaumann, S. Schumacher, A. Tauschwitz, D. Varentsov, K. Weyrich, X. Yu, B. Zielbauer, Zs. Major, P. Neumayer, D. Kraus","doi":"10.1063/5.0203005","DOIUrl":"https://doi.org/10.1063/5.0203005","url":null,"abstract":"We present in situ measurements of spectrally resolved X-ray scattering and X-ray diffraction from monocrystalline diamond samples heated with an intense pulse of heavy ions. In this way, we determine the samples’ heating dynamics and their microscopic and macroscopic structural integrity over a timespan of several microseconds. Connecting the ratio of elastic to inelastic scattering with state-of-the-art density functional theory molecular dynamics simulations allows the inference of average temperatures around 1300 K, in agreement with predictions from stopping power calculations. The simultaneous diffraction measurements show no hints of any volumetric graphitization of the material, but do indicate the onset of fracture in the diamond sample. Our experiments pave the way for future studies at the Facility for Antiproton and Ion Research, where a substantially increased intensity of the heavy ion beam will be available.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141353390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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