Sushil K. Singh, Michal Krupka, Josef Krasa, Valeria Istokskaia, Jan Dostal, Roman Dudzak, Tadeusz Pisarczyk, Jakub Cikhardt, Shubham Agarwal, Daniel Klir, Karel Rezac, Lorenzo Giuffrida, Tomasz Chodukowski, Zofia Rusiniak, Tomas Burian, Daniele Margarone, Miroslav Krus, Libor Juha
The interaction of focused high power laser beam with solid targets leads to acceleration of charged particles among other by non-linear effects in the plasma. In this experiment, the hot electrons are characterized from the interaction of sub-nanosecond and kilo-joule class laser pulse with thin metal foil targets (Cu, Ta, Ti, Sn, Pb). The energy distribution functions of electrons were measured by angularly resolved multichannel electron spectrometer. The hot electron temperatures were observed in range from 30 to 80 keV for laser intensities between ${sim}10^{15}$ and $3 times 10^{16} mathrm{W,cm^{-2}}$. The measured energy distribution and electron temperature were compared with published results and known scaling laws at higher laser intensities. For foil targets of different materials, the temperature and flux of hot electrons were scaled with target thickness in the range of 1–100 $unicode{x03BC}mathrm{m}$ from low Z to high Z materials where Z is the atomic number. The profile of conversion efficiency from laser energy to hot electrons is discussed in the energy range from 100 to 600 J. For the given laser and target parameters, the nonlinear behaviour of conversion efficiency and relevant physics are also described in detail.
聚焦的高功率激光束与固体靶相互作用时，等离子体中的非线性效应会导致带电粒子加速。在本实验中，亚纳秒级和千焦耳级激光脉冲与薄金属箔目标（铜、钽、钛、锡、铅）的相互作用产生了热电子。电子的能量分布函数是通过角分辨多通道电子能谱仪测量的。在激光强度介于 ${sim}10^{15}$ 和 $3 times 10^{16}mathrm{W,cm^{-2}}$ 之间时，观察到热电子温度在 30 至 80 keV 之间。测得的能量分布和电子温度与已公布的结果以及已知的更高激光强度下的缩放规律进行了比较。对于不同材料的箔靶，热电子的温度和通量与靶厚度成比例，从低 Z 到高 Z 材料的范围为 1-100 $unicode{x03BC}mathrm{m}$，其中 Z 是原子序数。对于给定的激光和靶参数，还详细描述了转换效率的非线性行为和相关物理特性。
{"title":"Hot electron emission characteristics from thin metal foil targets irradiated by terawatt laser","authors":"Sushil K. Singh, Michal Krupka, Josef Krasa, Valeria Istokskaia, Jan Dostal, Roman Dudzak, Tadeusz Pisarczyk, Jakub Cikhardt, Shubham Agarwal, Daniel Klir, Karel Rezac, Lorenzo Giuffrida, Tomasz Chodukowski, Zofia Rusiniak, Tomas Burian, Daniele Margarone, Miroslav Krus, Libor Juha","doi":"10.1017/lpb.2023.2","DOIUrl":"https://doi.org/10.1017/lpb.2023.2","url":null,"abstract":"The interaction of focused high power laser beam with solid targets leads to acceleration of charged particles among other by non-linear effects in the plasma. In this experiment, the hot electrons are characterized from the interaction of sub-nanosecond and kilo-joule class laser pulse with thin metal foil targets (Cu, Ta, Ti, Sn, Pb). The energy distribution functions of electrons were measured by angularly resolved multichannel electron spectrometer. The hot electron temperatures were observed in range from 30 to 80 keV for laser intensities between <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" mimetype=\"image\" xlink:href=\"S0263034623000022_inline1.png\" /> <jats:tex-math>${sim}10^{15}$</jats:tex-math> </jats:alternatives> </jats:inline-formula> and <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" mimetype=\"image\" xlink:href=\"S0263034623000022_inline2.png\" /> <jats:tex-math>$3 times 10^{16} mathrm{W,cm^{-2}}$</jats:tex-math> </jats:alternatives> </jats:inline-formula>. The measured energy distribution and electron temperature were compared with published results and known scaling laws at higher laser intensities. For foil targets of different materials, the temperature and flux of hot electrons were scaled with target thickness in the range of 1–100 <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" mimetype=\"image\" xlink:href=\"S0263034623000022_inline3.png\" /> <jats:tex-math>$unicode{x03BC}mathrm{m}$</jats:tex-math> </jats:alternatives> </jats:inline-formula> from low Z to high Z materials where Z is the atomic number. The profile of conversion efficiency from laser energy to hot electrons is discussed in the energy range from 100 to 600 J. For the given laser and target parameters, the nonlinear behaviour of conversion efficiency and relevant physics are also described in detail.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140612799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
L. Tyler Mix, James A. Maslow, Michael A. Jaworski, Joshua E. Coleman
Laser-driven X-rays as probes for high-energy-density physics spans an extremely large parameter space with laser intensities varying by 8 orders of magnitude. We have built and characterized a soft X-ray source driven by a modest intensity laser of 4 × 1013 W/cm2. Emitted X-rays were measured by diamond radiation detectors and a filtered soft X-ray camera. A material-dependence study on Al, Ti, stainless steel alloy 304, Fe, Cu and Sn targets indicated 5-μm-thick Cu foils produced the highest X-ray yield. X-ray emission in the laser direction and emission in the reverse direction depend strongly on the foil material and the thickness due to the opacity and hydrodynamic disassembly time. The time-varying X-ray signals are used to measure the material thinning rate and is found to be ∼1.5 μm/ns for the materials tested implying thermal temperature around 0.6 eV. The X-ray spectra from Cu targets peaks at ∼2 keV with no emission >4 keV and was estimated using images with eight different foil filters. One-dimensional hydrodynamic and spectral calculations using HELIOS-CR provide qualitative agreement with experimental results. Modest intensity lasers can be an excellent source for nanosecond bursts of soft X-rays.
激光驱动的 X 射线作为高能量密度物理学的探测器，其参数空间跨度极大，激光强度相差 8 个数量级。我们建造了一个由 4 × 1013 W/cm2 的中等强度激光驱动的软 X 射线源，并对其进行了表征。发射的 X 射线由金刚石辐射探测器和滤波软 X 射线照相机测量。对铝、钛、不锈钢合金 304、铁、铜和锡靶的材料依赖性研究表明，5μm 厚的铜箔产生的 X 射线产量最高。由于不透明性和流体动力分解时间的影响，激光方向的 X 射线发射和反向发射在很大程度上取决于箔的材料和厚度。时间变化的 X 射线信号用于测量材料的减薄率，在测试的材料中，减薄率为 ∼1.5 μm/ns，这意味着热温度约为 0.6 eV。铜靶的 X 射线光谱在 ∼2 keV 处达到峰值，在 4 keV 处没有发射。使用 HELIOS-CR 进行的一维流体力学和光谱计算与实验结果基本一致。强度适中的激光器是纳秒级软 X 射线猝发的绝佳来源。
{"title":"Flux and estimated spectra from a low-intensity laser-driven X-ray source","authors":"L. Tyler Mix, James A. Maslow, Michael A. Jaworski, Joshua E. Coleman","doi":"10.1017/lpb.2024.1","DOIUrl":"https://doi.org/10.1017/lpb.2024.1","url":null,"abstract":"Laser-driven X-rays as probes for high-energy-density physics spans an extremely large parameter space with laser intensities varying by 8 orders of magnitude. We have built and characterized a soft X-ray source driven by a modest intensity laser of 4 × 10<jats:sup>13</jats:sup> W/cm<jats:sup>2</jats:sup>. Emitted X-rays were measured by diamond radiation detectors and a filtered soft X-ray camera. A material-dependence study on Al, Ti, stainless steel alloy 304, Fe, Cu and Sn targets indicated 5-μm-thick Cu foils produced the highest X-ray yield. X-ray emission in the laser direction and emission in the reverse direction depend strongly on the foil material and the thickness due to the opacity and hydrodynamic disassembly time. The time-varying X-ray signals are used to measure the material thinning rate and is found to be ∼1.5 μm/ns for the materials tested implying thermal temperature around 0.6 eV. The X-ray spectra from Cu targets peaks at ∼2 keV with no emission >4 keV and was estimated using images with eight different foil filters. One-dimensional hydrodynamic and spectral calculations using HELIOS-CR provide qualitative agreement with experimental results. Modest intensity lasers can be an excellent source for nanosecond bursts of soft X-rays.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140566973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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. Maffini, M. Cipriani, D. Orecchia, V. Ciardiello, A. Formenti, F. Consoli, M. Passoni
Porous materials have peculiar characteristics that are relevant for inertial confinement fusion (ICF). Among them, chemically produced foams are proved to be able to smooth the laser inhomogeneities and to increase the coupling of the laser with the target. Foams realized with other elements and techniques may prove useful as well for ICF applications. In this work, we explore the potential of a novel class of porous materials for ICF, namely, carbon nanofoams produced with the pulsed laser deposition (PLD) technique, by means of hydrodynamic numerical simulations. By comparison with a simulation of solid-density carbon, PLD nanofoams show a higher pressure at the shock front, which could make them potential good candidates as ablators for a capsule for direct-drive fusion.
{"title":"Numerical Study of Carbon Nanofoam Targets for Laser-Driven Inertial Fusion Experiments","authors":"A. Maffini, M. Cipriani, D. Orecchia, V. Ciardiello, A. Formenti, F. Consoli, M. Passoni","doi":"10.1155/2023/1214430","DOIUrl":"https://doi.org/10.1155/2023/1214430","url":null,"abstract":"Porous materials have peculiar characteristics that are relevant for inertial confinement fusion (ICF). Among them, chemically produced foams are proved to be able to smooth the laser inhomogeneities and to increase the coupling of the laser with the target. Foams realized with other elements and techniques may prove useful as well for ICF applications. In this work, we explore the potential of a novel class of porous materials for ICF, namely, carbon nanofoams produced with the pulsed laser deposition (PLD) technique, by means of hydrodynamic numerical simulations. By comparison with a simulation of solid-density carbon, PLD nanofoams show a higher pressure at the shock front, which could make them potential good candidates as ablators for a capsule for direct-drive fusion.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88798907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
M. Geissel, A. Harvey-Thompson, M. Weis, Jefrey R. Fein, D. Ampleford, D. Bliss, Aaron M. Hansen, C. Jennings, M. Kimmel, P. Rambo, J. Shores, I. Smith, S. Speas, J. Porter
Helium or neopentane can be used as surrogate gas fill for deuterium (D2) or deuterium-tritium (DT) in laser-plasma interaction studies. Surrogates are convenient to avoid flammability hazards or the integration of cryogenics in an experiment. To test the degree of equivalency between deuterium and helium, experiments were conducted in the Pecos target chamber at Sandia National Laboratories. Observables such as laser propagation and signatures of laser-plasma instabilities (LPI) were recorded for multiple laser and target configurations. It was found that some observables can differ significantly despite the apparent similarity of the gases with respect to molecular charge and weight. While a qualitative behaviour of the interaction may very well be studied by finding a suitable compromise of laser absorption, electron density, and LPI cross sections, a quantitative investigation of expected values for deuterium fills at high laser intensities is not likely to succeed with surrogate gases.
{"title":"Helium as a Surrogate for Deuterium in LPI Studies","authors":"M. Geissel, A. Harvey-Thompson, M. Weis, Jefrey R. Fein, D. Ampleford, D. Bliss, Aaron M. Hansen, C. Jennings, M. Kimmel, P. Rambo, J. Shores, I. Smith, S. Speas, J. Porter","doi":"10.1155/2023/2083295","DOIUrl":"https://doi.org/10.1155/2023/2083295","url":null,"abstract":"Helium or neopentane can be used as surrogate gas fill for deuterium (D2) or deuterium-tritium (DT) in laser-plasma interaction studies. Surrogates are convenient to avoid flammability hazards or the integration of cryogenics in an experiment. To test the degree of equivalency between deuterium and helium, experiments were conducted in the Pecos target chamber at Sandia National Laboratories. Observables such as laser propagation and signatures of laser-plasma instabilities (LPI) were recorded for multiple laser and target configurations. It was found that some observables can differ significantly despite the apparent similarity of the gases with respect to molecular charge and weight. While a qualitative behaviour of the interaction may very well be studied by finding a suitable compromise of laser absorption, electron density, and LPI cross sections, a quantitative investigation of expected values for deuterium fills at high laser intensities is not likely to succeed with surrogate gases.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80404824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Liquid leaf targets show promise as high repetition rate targets for laser-based ion acceleration using the Target Normal Sheath Acceleration (TNSA) mechanism and are currently under development. In this work, we discuss the effects of different ion species and investigate how they can be leveraged for use as a possible laser-driven neutron source. To aid in this research, we develop a surrogate model for liquid leaf target laser-ion acceleration experiments, based on artificial neural networks. The model is trained using data from Particle-In-Cell (PIC) simulations. The fast inference speed of our deep learning model allows us to optimize experimental parameters for maximum ion energy and laser-energy conversion efficiency. An analysis of parameter influence on our model output, using Sobol’ and PAWN indices, provides deeper insights into the laser-plasma system.
{"title":"Modeling of a Liquid Leaf Target TNSA Experiment Using Particle-In-Cell Simulations and Deep Learning","authors":"B. Schmitz, Daniel Kreuter, O. Boine-Frankenheim","doi":"10.1155/2023/2868112","DOIUrl":"https://doi.org/10.1155/2023/2868112","url":null,"abstract":"Liquid leaf targets show promise as high repetition rate targets for laser-based ion acceleration using the Target Normal Sheath Acceleration (TNSA) mechanism and are currently under development. In this work, we discuss the effects of different ion species and investigate how they can be leveraged for use as a possible laser-driven neutron source. To aid in this research, we develop a surrogate model for liquid leaf target laser-ion acceleration experiments, based on artificial neural networks. The model is trained using data from Particle-In-Cell (PIC) simulations. The fast inference speed of our deep learning model allows us to optimize experimental parameters for maximum ion energy and laser-energy conversion efficiency. An analysis of parameter influence on our model output, using Sobol’ and PAWN indices, provides deeper insights into the laser-plasma system.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74850018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 laser-induced breakdown spectroscopy (LIBS) technique is one of the most promising laser-based analytical techniques. Coincidentally, the LIBS acronym was proposed by Radziemski and Loree in two seminal papers published in 1981, almost at the same time in which the Laser and Particle Beams journal started its publication. In this contribution, the evolution of the LIBS technique is discussed following a chronological collection of key papers in LIBS, some of which were in fact published on LPB.
{"title":"Forty Years of Laser-Induced Breakdown Spectroscopy and Laser and Particle Beams","authors":"V. Palleschi","doi":"10.1155/2023/2502152","DOIUrl":"https://doi.org/10.1155/2023/2502152","url":null,"abstract":"The laser-induced breakdown spectroscopy (LIBS) technique is one of the most promising laser-based analytical techniques. Coincidentally, the LIBS acronym was proposed by Radziemski and Loree in two seminal papers published in 1981, almost at the same time in which the Laser and Particle Beams journal started its publication. In this contribution, the evolution of the LIBS technique is discussed following a chronological collection of key papers in LIBS, some of which were in fact published on LPB.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84695309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 topic of proton-boron fusion has recently attracted considerable interest in the scientific community, both for its future perspectives for energy production and for nearer-term possibilities to realize high-brightness α-particle sources. Very interesting experimental results have been obtained, in particular in laser-driven experiments but also using other experimental approaches. The goal of this special issue is to collect the most recent developments in experiments, theory, advanced targetry, diagnostics, and numerical simulation codes.
{"title":"Advances in the Study of Laser-Driven Proton-Boron Fusion","authors":"D. Batani, D. Margarone, F. Belloni","doi":"10.1155/2023/9824024","DOIUrl":"https://doi.org/10.1155/2023/9824024","url":null,"abstract":"The topic of proton-boron fusion has recently attracted considerable interest in the scientific community, both for its future perspectives for energy production and for nearer-term possibilities to realize high-brightness α-particle sources. Very interesting experimental results have been obtained, in particular in laser-driven experiments but also using other experimental approaches. The goal of this special issue is to collect the most recent developments in experiments, theory, advanced targetry, diagnostics, and numerical simulation codes.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87599696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
M. Salvadori, M. Scisciò, G. Di Giorgio, M. Cipriani, P. Andreoli, G. Cristofari, R. De Angelis, D. Giulietti, F. Consoli
The energy problem is an open issue becoming increasingly pressing. The possibility to use nuclear fusion as an alternative energy source is thus acquiring progressively more importance and many investors are pushing to achieve the goal of an electric plant based on fusion. The most studied reaction is the deuterium-tritium one, but this poses several technical issues related to the handling of the radioactive fuel and neutron generation. In this frame, the aneutronic 11B(p, α)2α fusion reaction has attracted the interest of many researchers. Despite a fusion reactor based on pB is still a long-term goal, the study of this reaction is important both for astrophysics research and for its possible employment in schemes of high brightness source of α particles for applications, as for instance in medicine. Nevertheless, the univocal identification of the produced alphas is a well-known challenging task when the reaction is triggered by high-intensity lasers. Indeed, due to the multifaceted emission typical of laser-matter interactions, the signal coming from alphas is often superimposed to that generated by protons and by other ions, and in many cases, it is therefore hardly recognizable. In this work, we analysed the possibility of employing a Thomson spectrometer (TS) with an adequate differential filtering system for the exclusion from the α-particle trace, the contribution of all other ionic species. Moreover, for the energy ranges where the filtering method cannot be successfully applied, we investigated the feasibility of integrating in the TS assembly a particle detector for time-of-flight (TOF) measurements.
{"title":"Univocal Discrimination of α Particles Produced by 11B(p, α)2α Fusions in Laser-Matter Experiments by Advanced Thomson Spectrometry","authors":"M. Salvadori, M. Scisciò, G. Di Giorgio, M. Cipriani, P. Andreoli, G. Cristofari, R. De Angelis, D. Giulietti, F. Consoli","doi":"10.1155/2023/7831712","DOIUrl":"https://doi.org/10.1155/2023/7831712","url":null,"abstract":"The energy problem is an open issue becoming increasingly pressing. The possibility to use nuclear fusion as an alternative energy source is thus acquiring progressively more importance and many investors are pushing to achieve the goal of an electric plant based on fusion. The most studied reaction is the deuterium-tritium one, but this poses several technical issues related to the handling of the radioactive fuel and neutron generation. In this frame, the aneutronic 11B(p, α)2α fusion reaction has attracted the interest of many researchers. Despite a fusion reactor based on pB is still a long-term goal, the study of this reaction is important both for astrophysics research and for its possible employment in schemes of high brightness source of α particles for applications, as for instance in medicine. Nevertheless, the univocal identification of the produced alphas is a well-known challenging task when the reaction is triggered by high-intensity lasers. Indeed, due to the multifaceted emission typical of laser-matter interactions, the signal coming from alphas is often superimposed to that generated by protons and by other ions, and in many cases, it is therefore hardly recognizable. In this work, we analysed the possibility of employing a Thomson spectrometer (TS) with an adequate differential filtering system for the exclusion from the α-particle trace, the contribution of all other ionic species. Moreover, for the energy ranges where the filtering method cannot be successfully applied, we investigated the feasibility of integrating in the TS assembly a particle detector for time-of-flight (TOF) measurements.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75476448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Short-pulse, ultrahigh-intensity lasers have opened new regimes for studying fusion plasmas and creating novel ultrashort ion beams and neutron sources. Diagnosing the plasma in these experiments is important for optimizing the fusion yield but difficult due to the picosecond time scales, 10 s of micron-cubed volumes, and high densities. We propose to use the yields of photons and neutrons produced by parallel reactions involving the same reactants to diagnose the plasma conditions and predict the yields of specific reactions of interest. In this work, we focus on verifying the yield of the high-interest aneutronic proton-boron fusion reaction 11 B p , 2 α 4 H e , which is difficult to measure directly due to the short stopping range of the produced α s in most materials. We identify promising photon-producing reactions for this purpose and compute the ratios of the photon yield to the α yield as a function of plasma parameters. In beam-fusion experiments, the 11 C yield is an easily-measurable observable to verify the α yield. In light of our results, improving and extending measurements of the cross-sections for these parallel reactions are important steps to gain greater control over these laser-driven fusion plasmas.
短脉冲、超高强度激光为研究聚变等离子体和创造新型超短离子束和中子源开辟了新的途径。在这些实验中诊断等离子体对于优化聚变产量很重要，但由于皮秒时间尺度、10秒微米立方体积和高密度，诊断等离子体很困难。我们建议使用涉及相同反应物的平行反应产生的光子和中子的产率来诊断等离子体条件和预测特定反应的产率。在这项工作中，我们的重点是验证高兴趣的中子质子-硼聚变反应11 B p, 2 α 4 H e的产率，由于在大多数材料中产生的α s停止范围短，难以直接测量。我们为此目的确定了有前途的光子产生反应，并计算了光子产率与α产率的比值作为等离子体参数的函数。在束流聚变实验中，11c产率是验证α产率的一个容易测量的观测值。根据我们的结果，改进和扩展这些平行反应的横截面测量是更好地控制这些激光驱动的聚变等离子体的重要步骤。
{"title":"Photon and Neutron Production as In Situ Diagnostics of Proton-Boron Fusion","authors":"B. Hegelich, L. Labun, O. Z. Labun, T. Mehlhorn","doi":"10.1155/2023/6924841","DOIUrl":"https://doi.org/10.1155/2023/6924841","url":null,"abstract":"Short-pulse, ultrahigh-intensity lasers have opened new regimes for studying fusion plasmas and creating novel ultrashort ion beams and neutron sources. Diagnosing the plasma in these experiments is important for optimizing the fusion yield but difficult due to the picosecond time scales, 10 s of micron-cubed volumes, and high densities. We propose to use the yields of photons and neutrons produced by parallel reactions involving the same reactants to diagnose the plasma conditions and predict the yields of specific reactions of interest. In this work, we focus on verifying the yield of the high-interest aneutronic proton-boron fusion reaction \u0000 \u0000 \u0000 \u0000 \u0000 11\u0000 \u0000 \u0000 B\u0000 \u0000 \u0000 \u0000 \u0000 p\u0000 ,\u0000 2\u0000 α\u0000 \u0000 \u0000 \u0000 \u0000 4\u0000 \u0000 \u0000 H\u0000 e\u0000 \u0000 , which is difficult to measure directly due to the short stopping range of the produced \u0000 \u0000 α\u0000 s\u0000 \u0000 in most materials. We identify promising photon-producing reactions for this purpose and compute the ratios of the photon yield to the \u0000 \u0000 α\u0000 \u0000 yield as a function of plasma parameters. In beam-fusion experiments, the \u0000 \u0000 \u0000 \u0000 \u0000 11\u0000 \u0000 \u0000 C\u0000 \u0000 yield is an easily-measurable observable to verify the \u0000 \u0000 α\u0000 \u0000 yield. In light of our results, improving and extending measurements of the cross-sections for these parallel reactions are important steps to gain greater control over these laser-driven fusion plasmas.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75166919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
This study is the further research of the path encoding pulse compression technique. In this study, the regularity of pulse compression gain is studied by adopting the numerical simulation and experiment measurement methods. For the lossless cavity, the power gain has the characteristic of equal pulse length with equal compression gain contribution according to the numerical simulation results. It means that the pulse compression gain is increased linearly along with the time length of the input pulse. The obtained pulse power gains are equal for the two subpulses intercepted arbitrarily form the input pulse with equal time length for the pulse compression. For the lossy cavity, the power gain usually does not increase significantly after the length of input pulse reaches to a certain value. The gain contribution decreases gradually along with the increase of time length of input pulse until the growth rate of gain contribution equals to zero. Assuming two subpulses with equal time length were intercepted from the input pulse, the gain contribution of the earlier subpulse is lower than that of the later subpulse. The measured results verified the simulated gain contribution regularity according to the established experimental system.
{"title":"Study on Gain Regularity of High Power Microwave Obtained by Using Path Encoding Pulse Compression","authors":"Jinyong Fang, Chang Zhai, Jiangniu Wu, Haoliang Zhang, Huijun Huang","doi":"10.1155/2023/9101258","DOIUrl":"https://doi.org/10.1155/2023/9101258","url":null,"abstract":"This study is the further research of the path encoding pulse compression technique. In this study, the regularity of pulse compression gain is studied by adopting the numerical simulation and experiment measurement methods. For the lossless cavity, the power gain has the characteristic of equal pulse length with equal compression gain contribution according to the numerical simulation results. It means that the pulse compression gain is increased linearly along with the time length of the input pulse. The obtained pulse power gains are equal for the two subpulses intercepted arbitrarily form the input pulse with equal time length for the pulse compression. For the lossy cavity, the power gain usually does not increase significantly after the length of input pulse reaches to a certain value. The gain contribution decreases gradually along with the increase of time length of input pulse until the growth rate of gain contribution equals to zero. Assuming two subpulses with equal time length were intercepted from the input pulse, the gain contribution of the earlier subpulse is lower than that of the later subpulse. The measured results verified the simulated gain contribution regularity according to the established experimental system.","PeriodicalId":49925,"journal":{"name":"Laser and Particle Beams","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75772891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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