Abstract Exploiting high-energy electron beams colliding into high-intensity laser pulses brings an opportunity to reach high values of the dimensionless rest-frame acceleration $chi$ and thereby invoke processes described by strong-field quantum electrodynamics (SFQED). Measuring deviations from the results of Furry-picture perturbation theory in SFQED at high $chi$ can be valuable for testing existing predictions, as well as for guiding further theoretical developments. Nevertheless, such experimental measurements are challenging due to the probabilistic nature of the interaction processes, dominating signals of low- $chi$ interactions and limited capabilities to control and measure the alignment and synchronization in such collision experiments. Here we elaborate a methodology of using approximate Bayesian computations for drawing statistical inferences based on the results of many repeated experiments despite partially unknown collision parameters that vary between experiments. As a proof-of-principle, we consider the problem of inferring the effective mass change due to coupling with the strong-field environment.
{"title":"Prospects for statistical tests of strong-field quantum electrodynamics with high-intensity lasers","authors":"Christoffer Olofsson, A. Gonoskov","doi":"10.1017/hpl.2023.64","DOIUrl":"https://doi.org/10.1017/hpl.2023.64","url":null,"abstract":"Abstract Exploiting high-energy electron beams colliding into high-intensity laser pulses brings an opportunity to reach high values of the dimensionless rest-frame acceleration \u0000$chi$\u0000 and thereby invoke processes described by strong-field quantum electrodynamics (SFQED). Measuring deviations from the results of Furry-picture perturbation theory in SFQED at high \u0000$chi$\u0000 can be valuable for testing existing predictions, as well as for guiding further theoretical developments. Nevertheless, such experimental measurements are challenging due to the probabilistic nature of the interaction processes, dominating signals of low- \u0000$chi$\u0000 interactions and limited capabilities to control and measure the alignment and synchronization in such collision experiments. Here we elaborate a methodology of using approximate Bayesian computations for drawing statistical inferences based on the results of many repeated experiments despite partially unknown collision parameters that vary between experiments. As a proof-of-principle, we consider the problem of inferring the effective mass change due to coupling with the strong-field environment.","PeriodicalId":54285,"journal":{"name":"High Power Laser Science and Engineering","volume":"2 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72647343","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}
B. Loughran, M. Streeter, H. Ahmed, S. Astbury, M. Balcazar, M. Borghesi, N. Bourgeois, C. Curry, S. Dann, S. DiIorio, N. Dover, T. Dzelzanis, O. Ettlinger, M. Gauthier, L. Giuffrida, G. Glenn, S. Glenzer, J. Green, R. Gray, G. Hicks, C. Hyland, V. Istokskaia, M. King, D. Margarone, O. McCusker, P. McKenna, Z. Najmudin, C. Parisuaña, P. Parsons, C. Spindloe, D. Symes, A. Thomas, F. Treffert, N. Xu, C. Palmer
Abstract The interaction of relativistically intense lasers with opaque targets represents a highly non-linear, multi-dimensional parameter space. This 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 rates. High repetition-rate (HRR) lasers augmented by machine learning present a valuable opportunity for efficient source optimization. Here, 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 energy. This demonstration of automated optimization of laser-driven proton beams is a crucial step towards deeper physical insight and the construction of future radiation sources.
{"title":"Automated control and optimization of laser-driven ion acceleration","authors":"B. Loughran, M. Streeter, H. Ahmed, S. Astbury, M. Balcazar, M. Borghesi, N. Bourgeois, C. Curry, S. Dann, S. DiIorio, N. Dover, T. Dzelzanis, O. Ettlinger, M. Gauthier, L. Giuffrida, G. Glenn, S. Glenzer, J. Green, R. Gray, G. Hicks, C. Hyland, V. Istokskaia, M. King, D. Margarone, O. McCusker, P. McKenna, Z. Najmudin, C. Parisuaña, P. Parsons, C. Spindloe, D. Symes, A. Thomas, F. Treffert, N. Xu, C. Palmer","doi":"10.1017/hpl.2023.23","DOIUrl":"https://doi.org/10.1017/hpl.2023.23","url":null,"abstract":"Abstract The interaction of relativistically intense lasers with opaque targets represents a highly non-linear, multi-dimensional parameter space. This 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 rates. High repetition-rate (HRR) lasers augmented by machine learning present a valuable opportunity for efficient source optimization. Here, 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 energy. This demonstration of automated optimization of laser-driven proton beams is a crucial step towards deeper physical insight and the construction of future radiation sources.","PeriodicalId":54285,"journal":{"name":"High Power Laser Science and Engineering","volume":"17 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83587905","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}
Yulong Cui, Xin Tian, Binyu Rao, Hao Li, Wei Huang, Wenxi Pei, M. Wang, Zilun Chen, Zefeng Wang
Abstract We report here the first hundred-watt continuous wave fiber gas laser in H2-filled hollow-core photonic crystal fiber (PCF) by stimulated Raman scattering. The pump source is a homemade narrow-linewidth fiber oscillator with a 3 dB linewidth of 0.15 nm at the maximum output power of 380 W. To efficiently and stably couple several-hundred-watt pump power into the hollow core and seal the gas, a hollow-core fiber end-cap is fabricated and used at the input end. A maximum power of 110 W at 1153 nm is obtained in a 5 m long hollow-core PCF filled with 36 bar H2, and the conversion efficiency of the first Stokes power is around 48.9%. This work paves the way for high-power fiber gas Raman lasers.
本文报道了利用受激拉曼散射在h2填充空心光子晶体光纤(PCF)中实现的首个百瓦连续波光纤气体激光器。泵浦源为国产窄线宽光纤振荡器，线宽为3db, 0.15 nm，最大输出功率为380w。为了高效、稳定地将几百瓦的泵浦功率耦合到空芯中并对气体进行密封，在输入端制作了空心光纤端盖。在长5 m、填充36 bar H2的空心PCF中，在1153 nm处获得了110 W的最大功率，第一Stokes功率的转换效率约为48.9%。这项工作为高功率光纤气体拉曼激光器铺平了道路。
{"title":"A 110 W fiber gas Raman laser at 1153 nm","authors":"Yulong Cui, Xin Tian, Binyu Rao, Hao Li, Wei Huang, Wenxi Pei, M. Wang, Zilun Chen, Zefeng Wang","doi":"10.1017/hpl.2022.43","DOIUrl":"https://doi.org/10.1017/hpl.2022.43","url":null,"abstract":"Abstract We report here the first hundred-watt continuous wave fiber gas laser in H2-filled hollow-core photonic crystal fiber (PCF) by stimulated Raman scattering. The pump source is a homemade narrow-linewidth fiber oscillator with a 3 dB linewidth of 0.15 nm at the maximum output power of 380 W. To efficiently and stably couple several-hundred-watt pump power into the hollow core and seal the gas, a hollow-core fiber end-cap is fabricated and used at the input end. A maximum power of 110 W at 1153 nm is obtained in a 5 m long hollow-core PCF filled with 36 bar H2, and the conversion efficiency of the first Stokes power is around 48.9%. This work paves the way for high-power fiber gas Raman lasers.","PeriodicalId":54285,"journal":{"name":"High Power Laser Science and Engineering","volume":"49 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76213611","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}
M. Martyanov, V. Ginzburg, A. Balakin, S. Skobelev, D. Silin, A. Kochetkov, I. Yakovlev, Alexey Kuzmin, S. Mironov, I. Shaikin, Sergey Stukachev, A. Shaykin, E. Khazanov, A. Litvak
Abstract It was shown experimentally that for a 65-fs 17-J pulse, the effect of filamentation instability, also known as small-scale self-focusing, is much weaker than that predicted by stationary and nonstationary theoretical models for high B-integral values. Although this discrepancy has been left unexplained at the moment, in practice no signs of filamentation may allow a breakthrough in nonlinear pulse post-compression at high laser energy.
{"title":"Suppressing small-scale self-focusing of high-power femtosecond pulses","authors":"M. Martyanov, V. Ginzburg, A. Balakin, S. Skobelev, D. Silin, A. Kochetkov, I. Yakovlev, Alexey Kuzmin, S. Mironov, I. Shaikin, Sergey Stukachev, A. Shaykin, E. Khazanov, A. Litvak","doi":"10.1017/hpl.2023.20","DOIUrl":"https://doi.org/10.1017/hpl.2023.20","url":null,"abstract":"Abstract It was shown experimentally that for a 65-fs 17-J pulse, the effect of filamentation instability, also known as small-scale self-focusing, is much weaker than that predicted by stationary and nonstationary theoretical models for high B-integral values. Although this discrepancy has been left unexplained at the moment, in practice no signs of filamentation may allow a breakthrough in nonlinear pulse post-compression at high laser energy.","PeriodicalId":54285,"journal":{"name":"High Power Laser Science and Engineering","volume":"41 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75322255","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}
Y. Wang, S. Weng, P. Li, Z. Shen, X. Jiang, J. Huang, X. L. Zhu, H. Ma, X. B. Zhang, X. Li, Z. Sheng, J. Zhang
Abstract As a typical plasma-based optical element that can sustain ultra-high light intensity, plasma density gratings driven by intense laser pulses have been extensively studied for wide applications. Here, we show that the plasma density grating driven by two intersecting driver laser pulses is not only nonuniform in space but also varies over time. Consequently, the probe laser pulse that passes through such a dynamic plasma density grating will be depolarized, that is, its polarization becomes spatially and temporally variable. More importantly, the laser depolarization may spontaneously take place for crossed laser beams if their polarization angles are arranged properly. The laser depolarization by a dynamic plasma density grating may find application in mitigating parametric instabilities in laser-driven inertial confinement fusion.
{"title":"Depolarization of intense laser beams by dynamic plasma density gratings","authors":"Y. Wang, S. Weng, P. Li, Z. Shen, X. Jiang, J. Huang, X. L. Zhu, H. Ma, X. B. Zhang, X. Li, Z. Sheng, J. Zhang","doi":"10.1017/hpl.2023.19","DOIUrl":"https://doi.org/10.1017/hpl.2023.19","url":null,"abstract":"Abstract As a typical plasma-based optical element that can sustain ultra-high light intensity, plasma density gratings driven by intense laser pulses have been extensively studied for wide applications. Here, we show that the plasma density grating driven by two intersecting driver laser pulses is not only nonuniform in space but also varies over time. Consequently, the probe laser pulse that passes through such a dynamic plasma density grating will be depolarized, that is, its polarization becomes spatially and temporally variable. More importantly, the laser depolarization may spontaneously take place for crossed laser beams if their polarization angles are arranged properly. The laser depolarization by a dynamic plasma density grating may find application in mitigating parametric instabilities in laser-driven inertial confinement fusion.","PeriodicalId":54285,"journal":{"name":"High Power Laser Science and Engineering","volume":"1 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89341271","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}
S. Gerlach, F. Balling, A. Schmidt, F. Brack, F. Kroll, J. Metzkes-Ng, M. Reimold, U. Schramm, M. Speicher, K. Zeil, K. Parodi, J. Schreiber
Abstract The acoustic pulse emitted from the Bragg peak of a laser-accelerated proton bunch focused into water has recently enabled the reconstruction of the bunch energy distribution. By adding three ultrasonic transducers and implementing a fast data analysis of the filtered raw signals, I-BEAT (Ion-Bunch Energy Acoustic Tracing) 3D now provides the mean bunch energy and absolute lateral bunch position in real-time and for individual bunches. Relative changes in energy spread and lateral bunch size can also be monitored. Our experiments at DRACO with proton bunch energies between 10 and 30 MeV reveal sub-MeV and sub-mm resolution. In addition to this 3D bunch information, the signal strength correlates also with the absolute bunch particle number.
{"title":"Three-dimensional acoustic monitoring of laser-accelerated protons in the focus of a pulsed-power solenoid lens","authors":"S. Gerlach, F. Balling, A. Schmidt, F. Brack, F. Kroll, J. Metzkes-Ng, M. Reimold, U. Schramm, M. Speicher, K. Zeil, K. Parodi, J. Schreiber","doi":"10.1017/hpl.2023.16","DOIUrl":"https://doi.org/10.1017/hpl.2023.16","url":null,"abstract":"Abstract The acoustic pulse emitted from the Bragg peak of a laser-accelerated proton bunch focused into water has recently enabled the reconstruction of the bunch energy distribution. By adding three ultrasonic transducers and implementing a fast data analysis of the filtered raw signals, I-BEAT (Ion-Bunch Energy Acoustic Tracing) 3D now provides the mean bunch energy and absolute lateral bunch position in real-time and for individual bunches. Relative changes in energy spread and lateral bunch size can also be monitored. Our experiments at DRACO with proton bunch energies between 10 and 30 MeV reveal sub-MeV and sub-mm resolution. In addition to this 3D bunch information, the signal strength correlates also with the absolute bunch particle number.","PeriodicalId":54285,"journal":{"name":"High Power Laser Science and Engineering","volume":"5 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79821865","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}
Nils Weiße, Leonard Doyle, J. Gebhard, F. Balling, F. Schweiger, F. Haberstroh, L. Geulig, Jinpu Lin, F. Irshad, J. Esslinger, S. Gerlach, M. Gilljohann, Vignesh Vaidyanathan, Dennis Siebert, A. Münzer, G. Schilling, Jörg Schreiber, P. Thirolf, S. Karsch, A. Döpp
Abstract The Centre for Advanced Laser Applications in Garching, Germany, is home to the ATLAS-3000 multi-petawatt laser, dedicated to research on laser particle acceleration and its applications. A control system based on Tango Controls is implemented for both the laser and four experimental areas. The device server approach features high modularity, which, in addition to the hardware control, enables a quick extension of the system and allows for automated data acquisition of the laser parameters and experimental data for each laser shot. In this paper we present an overview of our implementation of the control system, as well as our advances in terms of experimental operation, online supervision and data processing. We also give an outlook on advanced experimental supervision and online data evaluation – where the data can be processed in a pipeline – which is being developed on the basis of this infrastructure.
{"title":"Tango Controls and data pipeline for petawatt laser experiments","authors":"Nils Weiße, Leonard Doyle, J. Gebhard, F. Balling, F. Schweiger, F. Haberstroh, L. Geulig, Jinpu Lin, F. Irshad, J. Esslinger, S. Gerlach, M. Gilljohann, Vignesh Vaidyanathan, Dennis Siebert, A. Münzer, G. Schilling, Jörg Schreiber, P. Thirolf, S. Karsch, A. Döpp","doi":"10.1017/hpl.2023.17","DOIUrl":"https://doi.org/10.1017/hpl.2023.17","url":null,"abstract":"Abstract The Centre for Advanced Laser Applications in Garching, Germany, is home to the ATLAS-3000 multi-petawatt laser, dedicated to research on laser particle acceleration and its applications. A control system based on Tango Controls is implemented for both the laser and four experimental areas. The device server approach features high modularity, which, in addition to the hardware control, enables a quick extension of the system and allows for automated data acquisition of the laser parameters and experimental data for each laser shot. In this paper we present an overview of our implementation of the control system, as well as our advances in terms of experimental operation, online supervision and data processing. We also give an outlook on advanced experimental supervision and online data evaluation – where the data can be processed in a pipeline – which is being developed on the basis of this infrastructure.","PeriodicalId":54285,"journal":{"name":"High Power Laser Science and Engineering","volume":"34 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87295887","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}
Wenhao Wang, Yudong Tao, Jingui Ma, Jing Wang, P. Yuan, Dongfang Zhang, L. Qian
Abstract Parametric interaction allows both forward and backward energy transfers among the three interacting waves. The back-conversion effect is usually detrimental when unidirectional energy transfer is desired. In this theoretical work, we manifest that the back-conversion effect underpins the direct generation of the picosecond pulse train without the need for a laser resonator. The research scenario is an optical parametric amplification (OPA) that consists of a second-order nonlinear medium, a quasi-continuous pump laser and a sinusoidal amplitude-modulated seed signal. The back-conversion of OPA can transfer the modulation peaks (valleys) of the incident signal into output valleys (peaks), which inherently induces spectral sidebands. The generation of each sideband is naturally accompanied with a phase shift of ±π. In the regime of full-back-conversion, the amount and amplitude of the sidebands reach the maximum simultaneously, and their phase constitutes an arithmetic sequence, leading to the production of a picosecond pulse train. The generated picosecond pulse train can have an ultrahigh repetition rate of 40 GHz or higher, which may facilitate ultrafast applications with ultrahigh speed.
{"title":"Parametric generation and phase locking of multiple sidebands in the regime of full-back-conversion","authors":"Wenhao Wang, Yudong Tao, Jingui Ma, Jing Wang, P. Yuan, Dongfang Zhang, L. Qian","doi":"10.1017/hpl.2023.14","DOIUrl":"https://doi.org/10.1017/hpl.2023.14","url":null,"abstract":"Abstract Parametric interaction allows both forward and backward energy transfers among the three interacting waves. The back-conversion effect is usually detrimental when unidirectional energy transfer is desired. In this theoretical work, we manifest that the back-conversion effect underpins the direct generation of the picosecond pulse train without the need for a laser resonator. The research scenario is an optical parametric amplification (OPA) that consists of a second-order nonlinear medium, a quasi-continuous pump laser and a sinusoidal amplitude-modulated seed signal. The back-conversion of OPA can transfer the modulation peaks (valleys) of the incident signal into output valleys (peaks), which inherently induces spectral sidebands. The generation of each sideband is naturally accompanied with a phase shift of ±π. In the regime of full-back-conversion, the amount and amplitude of the sidebands reach the maximum simultaneously, and their phase constitutes an arithmetic sequence, leading to the production of a picosecond pulse train. The generated picosecond pulse train can have an ultrahigh repetition rate of 40 GHz or higher, which may facilitate ultrafast applications with ultrahigh speed.","PeriodicalId":54285,"journal":{"name":"High Power Laser Science and Engineering","volume":"120 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75789653","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}
G. Cristoforetti, P. Koester, S. Atzeni, D. Batani, S. Fujioka, Y. Hironaka, S. Hüller, T. Idesaka, K. Katagiri, K. Kawasaki, R. Kodama, D. Mancelli, P. Nicolai, N. Ozaki, A. Schiavi, K. Shigemori, R. Takizawa, T. Tamagawa, D. Tanaka, A. Tentori, Y. Umeda, A. Yogo, L. Gizzi
Abstract Laser–plasma interaction and hot electrons have been characterized in detail in laser irradiation conditions relevant for direct-drive inertial confinement fusion. The experiment was carried out at the Gekko XII laser facility in multibeam planar target geometry at an intensity of approximately $3times {10}^{15}$ W/cm2. Experimental data suggest that high-energy electrons, with temperatures of 20–50 keV and conversion efficiencies of $eta <1%$ , were mainly produced by the damping of electron plasma waves driven by two-plasmon decay (TPD). Stimulated Raman scattering (SRS) is observed in a near-threshold growth regime, producing a reflectivity of approximately $0.01%$ , and is well described by an analytical model accounting for the convective growth in independent speckles. The experiment reveals that both TPD and SRS are collectively driven by multiple beams, resulting in a more vigorous growth than that driven by single-beam laser intensity.
{"title":"Multibeam laser–plasma interaction at the Gekko XII laser facility in conditions relevant for direct-drive inertial confinement fusion","authors":"G. Cristoforetti, P. Koester, S. Atzeni, D. Batani, S. Fujioka, Y. Hironaka, S. Hüller, T. Idesaka, K. Katagiri, K. Kawasaki, R. Kodama, D. Mancelli, P. Nicolai, N. Ozaki, A. Schiavi, K. Shigemori, R. Takizawa, T. Tamagawa, D. Tanaka, A. Tentori, Y. Umeda, A. Yogo, L. Gizzi","doi":"10.1017/hpl.2023.13","DOIUrl":"https://doi.org/10.1017/hpl.2023.13","url":null,"abstract":"Abstract Laser–plasma interaction and hot electrons have been characterized in detail in laser irradiation conditions relevant for direct-drive inertial confinement fusion. The experiment was carried out at the Gekko XII laser facility in multibeam planar target geometry at an intensity of approximately \u0000$3times {10}^{15}$\u0000 W/cm2. Experimental data suggest that high-energy electrons, with temperatures of 20–50 keV and conversion efficiencies of \u0000$eta <1%$\u0000 , were mainly produced by the damping of electron plasma waves driven by two-plasmon decay (TPD). Stimulated Raman scattering (SRS) is observed in a near-threshold growth regime, producing a reflectivity of approximately \u0000$0.01%$\u0000 , and is well described by an analytical model accounting for the convective growth in independent speckles. The experiment reveals that both TPD and SRS are collectively driven by multiple beams, resulting in a more vigorous growth than that driven by single-beam laser intensity.","PeriodicalId":54285,"journal":{"name":"High Power Laser Science and Engineering","volume":"45 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84644824","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}
Abstract Attosecond soft X-ray pulses are of great importance for the study of ultrafast electronic phenomena. In this paper, a feasible method is proposed to generate isolated fully coherent attosecond soft X-ray free electron laser via optical frequency beating. Two optical lasers with the opposite frequency chirps are used to induce a gradient frequency energy modulation, which helps to generate a gradually varied spacing electron pulse train. Subsequently, the undulator sections with electron beam delay lines are used to amplify the target ultra-short radiation. Numerical start-to-end simulations have been performed and the results demonstrate that an isolated soft X-ray pulse with the peak power of 330 GW and pulse duration of 620 as can be achieved by the proposed technique.
{"title":"Optical beat notes assisted attosecond soft X-ray pulse generation in high-gain free electron lasers","authors":"Zhen Wang, C. Feng","doi":"10.1017/hpl.2023.15","DOIUrl":"https://doi.org/10.1017/hpl.2023.15","url":null,"abstract":"Abstract Attosecond soft X-ray pulses are of great importance for the study of ultrafast electronic phenomena. In this paper, a feasible method is proposed to generate isolated fully coherent attosecond soft X-ray free electron laser via optical frequency beating. Two optical lasers with the opposite frequency chirps are used to induce a gradient frequency energy modulation, which helps to generate a gradually varied spacing electron pulse train. Subsequently, the undulator sections with electron beam delay lines are used to amplify the target ultra-short radiation. Numerical start-to-end simulations have been performed and the results demonstrate that an isolated soft X-ray pulse with the peak power of 330 GW and pulse duration of 620 as can be achieved by the proposed technique.","PeriodicalId":54285,"journal":{"name":"High Power Laser Science and Engineering","volume":"44 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2023-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79089335","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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