A new mechanism for the generation of high intensity speckles by coupling of overlapping beams is discovered and studied in detail. Using three-dimensional simulations, the coupling of overlapping beams smoothed by phase plates and by polarization smoothing are investigated in the regime relevant to inertial confinement fusion studies. It is found that the intensity distribution of the laser beam spot can be changed by nonuniform spatial phase modulation, and the speckles formed by the phase plate can be split into smaller speckles with higher intensities, which is favorable for the generation of laser plasma instabilities. Stimulated Brillouin scattering is compared in simulations with and without coupling of the overlapping incident beams, and the results confirm the enhancement of stimulated Brillouin scattering due to this mechanism.
{"title":"Generation of high intensity speckles in overlapping laser beams","authors":"L. Hao, J. Qiu, W. Huo","doi":"10.1063/5.0123585","DOIUrl":"https://doi.org/10.1063/5.0123585","url":null,"abstract":"A new mechanism for the generation of high intensity speckles by coupling of overlapping beams is discovered and studied in detail. Using three-dimensional simulations, the coupling of overlapping beams smoothed by phase plates and by polarization smoothing are investigated in the regime relevant to inertial confinement fusion studies. It is found that the intensity distribution of the laser beam spot can be changed by nonuniform spatial phase modulation, and the speckles formed by the phase plate can be split into smaller speckles with higher intensities, which is favorable for the generation of laser plasma instabilities. Stimulated Brillouin scattering is compared in simulations with and without coupling of the overlapping incident beams, and the results confirm the enhancement of stimulated Brillouin scattering due to this mechanism.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"10 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88666686","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}
Over the last two decades, the importance of fully ionized plasmas for the controlled manipulation of high-power coherent light has increased considerably. Many ideas have been put forward on how to control or change the properties of laser pulses such as their frequency, spectrum, intensity, and polarization. The corresponding interaction with a plasma can take place either in a self-organizing way or by prior tailoring. Considerable work has been done in theoretical studies and in simulations, but at present there is a backlog of demand for experimental verification and the associated detailed characterization of plasma-optical elements. Existing proof-of-principle experiments need to be pushed to higher power levels. There is little doubt that plasmas have huge potential for future use in high-power optics. This introduction to the special issue of Matter and Radiation at Extremes devoted to plasma optics sets the framework, gives a short historical overview, and briefly describes the various articles in this collection.
{"title":"Plasma optics: A perspective for high-power coherent light generation and manipulation","authors":"C. Riconda, S. Weber","doi":"10.1063/5.0138996","DOIUrl":"https://doi.org/10.1063/5.0138996","url":null,"abstract":"Over the last two decades, the importance of fully ionized plasmas for the controlled manipulation of high-power coherent light has increased considerably. Many ideas have been put forward on how to control or change the properties of laser pulses such as their frequency, spectrum, intensity, and polarization. The corresponding interaction with a plasma can take place either in a self-organizing way or by prior tailoring. Considerable work has been done in theoretical studies and in simulations, but at present there is a backlog of demand for experimental verification and the associated detailed characterization of plasma-optical elements. Existing proof-of-principle experiments need to be pushed to higher power levels. There is little doubt that plasmas have huge potential for future use in high-power optics. This introduction to the special issue of Matter and Radiation at Extremes devoted to plasma optics sets the framework, gives a short historical overview, and briefly describes the various articles in this collection.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"7 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84161482","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}
With the advent of new synchrotron radiation x-ray sources that provide a significantly enhanced coherent flux, high-energy x-ray photon correlation spectroscopy measurements can be performed on materials in a diamond anvil cell. Essential information on atomic dynamics that was previously inaccessible can be obtained for various novel phenomena emerging under extreme conditions. This article discusses the importance, feasibility, and experimental details of this technique, as well as the opportunities that it offers to address critical scientific challenges.
{"title":"In situ high-pressure wide-angle hard x-ray photon correlation spectroscopy: A versatile tool probing atomic dynamics of extreme condition matter","authors":"Q. Zeng","doi":"10.1063/5.0146660","DOIUrl":"https://doi.org/10.1063/5.0146660","url":null,"abstract":"With the advent of new synchrotron radiation x-ray sources that provide a significantly enhanced coherent flux, high-energy x-ray photon correlation spectroscopy measurements can be performed on materials in a diamond anvil cell. Essential information on atomic dynamics that was previously inaccessible can be obtained for various novel phenomena emerging under extreme conditions. This article discusses the importance, feasibility, and experimental details of this technique, as well as the opportunities that it offers to address critical scientific challenges.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"38 4","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72481898","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}
N. Bukharskii, O. E. Vais, P. Korneev, V. Bychenkov
A neural network-based approach is proposed both for reconstructing the focal spot intensity profile and for estimating the peak intensity of a high-power tightly focused laser pulse using the angular energy distributions of protons accelerated by the pulse from rarefied gases. For these purposes, we use a convolutional neural network architecture. Training and testing datasets are calculated using the test particle method, with the laser description in the form of Stratton–Chu integrals, which model laser pulses focused by an off-axis parabolic mirror down to the diffraction limit. To demonstrate the power and robustness of this method, we discuss the reconstruction of axially symmetric intensity profiles for laser pulses with intensities and focal diameters in the ranges of 1021–1023 W cm−2 and ∼(1–4) λ, respectively. This approach has prospects for implementation at higher intensities and with asymmetric laser beams, and it can provide a valuable diagnostic method for emerging extremely intense laser facilities.
提出了一种基于神经网络的方法，利用稀薄气体脉冲加速质子的角能分布，重建高功率紧密聚焦激光脉冲的焦点光斑强度分布图，并估计其峰值强度。出于这些目的，我们使用卷积神经网络架构。训练和测试数据集使用测试粒子法计算，激光描述以Stratton-Chu积分的形式进行，该积分模拟了由离轴抛物面镜聚焦到衍射极限的激光脉冲。为了证明该方法的有效性和鲁棒性，我们讨论了在1021-1023 W cm−2和~ (1-4)λ范围内的激光脉冲的轴对称强度分布的重建。该方法在高强度和非对称激光束下具有应用前景，可以为新兴的极强激光设备提供一种有价值的诊断方法。
{"title":"Restoration of the focal parameters for an extreme-power laser pulse with ponderomotively scattered proton spectra by using a neural network algorithm","authors":"N. Bukharskii, O. E. Vais, P. Korneev, V. Bychenkov","doi":"10.1063/5.0126571","DOIUrl":"https://doi.org/10.1063/5.0126571","url":null,"abstract":"A neural network-based approach is proposed both for reconstructing the focal spot intensity profile and for estimating the peak intensity of a high-power tightly focused laser pulse using the angular energy distributions of protons accelerated by the pulse from rarefied gases. For these purposes, we use a convolutional neural network architecture. Training and testing datasets are calculated using the test particle method, with the laser description in the form of Stratton–Chu integrals, which model laser pulses focused by an off-axis parabolic mirror down to the diffraction limit. To demonstrate the power and robustness of this method, we discuss the reconstruction of axially symmetric intensity profiles for laser pulses with intensities and focal diameters in the ranges of 1021–1023 W cm−2 and ∼(1–4) λ, respectively. This approach has prospects for implementation at higher intensities and with asymmetric laser beams, and it can provide a valuable diagnostic method for emerging extremely intense laser facilities.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"18 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85324512","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}
Zhaoli Li, Y. Zuo, X. Zeng, Zhaohui Wu, Xiao-dong Wang, Xiao Wang, J. Mu, B. Hu
Ultraintense short-period infrared laser pulses play an important role in frontier scientific research, but their power is quite low when generated using current technology. This paper demonstrates a scheme for generating an ultraintense few-cycle infrared pulse by directly compressing a long infrared pulse. In this scheme, an infrared picosecond-to-nanosecond laser pulse counterpropagates with a rapidly extending plasma grating that is created by ionizing an undulated gas by a short laser pulse, and the infrared laser pulse is reflected by the rapidly extending plasma grating. Because of the high expansion velocity of the latter, the infrared laser pulse is compressed in the reflection process. One- and two-dimensional particle-in-cell simulations show that by this method, a pulse with a duration of tens of picoseconds in the mid- to far-infrared range can be compressed to a few cycles with an efficiency exceeding 60%, thereby making ultraintense few-cycle infrared pulses possible.
{"title":"Ultraintense few-cycle infrared laser generation by fast-extending plasma grating","authors":"Zhaoli Li, Y. Zuo, X. Zeng, Zhaohui Wu, Xiao-dong Wang, Xiao Wang, J. Mu, B. Hu","doi":"10.1063/5.0119868","DOIUrl":"https://doi.org/10.1063/5.0119868","url":null,"abstract":"Ultraintense short-period infrared laser pulses play an important role in frontier scientific research, but their power is quite low when generated using current technology. This paper demonstrates a scheme for generating an ultraintense few-cycle infrared pulse by directly compressing a long infrared pulse. In this scheme, an infrared picosecond-to-nanosecond laser pulse counterpropagates with a rapidly extending plasma grating that is created by ionizing an undulated gas by a short laser pulse, and the infrared laser pulse is reflected by the rapidly extending plasma grating. Because of the high expansion velocity of the latter, the infrared laser pulse is compressed in the reflection process. One- and two-dimensional particle-in-cell simulations show that by this method, a pulse with a duration of tens of picoseconds in the mid- to far-infrared range can be compressed to a few cycles with an efficiency exceeding 60%, thereby making ultraintense few-cycle infrared pulses possible.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"60 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84017445","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 inverse Faraday effect (IFE), which usually refers to the phenomenon in which a quasi-static axial magnetic field is self-generated when a circularly polarized beam propagates in a plasma, has rarely been studied for lasers with unconventional polarization states. In this paper, IFE is reconsidered for weakly relativistic full Poincaré beams, which can contain all possible laser polarization states. Starting from cold electron fluid equations and the conservation of generalized vorticity, a self-consistent theoretical model combining the nonlinear azimuthal current and diamagnetic current is presented. The theoretical results show that when such a laser propagates in a plasma, an azimuthally varying quasi-static axial magnetic field can be generated, which is quite different from the circularly polarized case. These results are qualitatively and quantitatively verified by three-dimensional particle-in-cell simulations. Our work extends the theoretical understanding of the IFE and provides a new degree of freedom in the design of magnetized plasma devices.
{"title":"Inverse Faraday effect of weakly relativistic full Poincaré beams in plasma","authors":"Wei Liu, Q. Jia, Jian Zheng","doi":"10.1063/5.0120072","DOIUrl":"https://doi.org/10.1063/5.0120072","url":null,"abstract":"The inverse Faraday effect (IFE), which usually refers to the phenomenon in which a quasi-static axial magnetic field is self-generated when a circularly polarized beam propagates in a plasma, has rarely been studied for lasers with unconventional polarization states. In this paper, IFE is reconsidered for weakly relativistic full Poincaré beams, which can contain all possible laser polarization states. Starting from cold electron fluid equations and the conservation of generalized vorticity, a self-consistent theoretical model combining the nonlinear azimuthal current and diamagnetic current is presented. The theoretical results show that when such a laser propagates in a plasma, an azimuthally varying quasi-static axial magnetic field can be generated, which is quite different from the circularly polarized case. These results are qualitatively and quantitatively verified by three-dimensional particle-in-cell simulations. Our work extends the theoretical understanding of the IFE and provides a new degree of freedom in the design of magnetized plasma devices.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"20 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75233714","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}
We present a novel scheme for dense electron acceleration driven by the laser irradiation of a near-critical-density plasma. The electron reflux effect in a transversely tailored plasma is particularly enhanced in the area of peak density. We observe a bubble-like distribution of re-injected electrons, which forms a strong quasistatic electromagnetic field that can accelerate electrons longitudinally while also preserving the electron transverse emittance. Simulation results demonstrate that over-dense electrons could be trapped in such an artificial bubble and accelerated to an energy of [Formula: see text]. The obtained relativistic electron beam can reach a total charge of up to 0.26 nC and is well collimated with a small divergence of 17 mrad. Moreover, the wavelength of electron oscillation is noticeably reduced due to the shaking of the bubble structure in the laser field. As a result, the energy of the produced photons is substantially increased to the γ range. This new regime provides a path to generating high-charge electron beams and high-energy γ-ray sources.
{"title":"Overcritical electron acceleration and betatron radiation in the bubble-like structure formed by re-injected electrons in a tailored transverse plasma","authors":"Yuan Zhao, Haiyang Lu, Cang-tao Zhou, Jungao Zhu","doi":"10.1063/5.0121558","DOIUrl":"https://doi.org/10.1063/5.0121558","url":null,"abstract":"We present a novel scheme for dense electron acceleration driven by the laser irradiation of a near-critical-density plasma. The electron reflux effect in a transversely tailored plasma is particularly enhanced in the area of peak density. We observe a bubble-like distribution of re-injected electrons, which forms a strong quasistatic electromagnetic field that can accelerate electrons longitudinally while also preserving the electron transverse emittance. Simulation results demonstrate that over-dense electrons could be trapped in such an artificial bubble and accelerated to an energy of [Formula: see text]. The obtained relativistic electron beam can reach a total charge of up to 0.26 nC and is well collimated with a small divergence of 17 mrad. Moreover, the wavelength of electron oscillation is noticeably reduced due to the shaking of the bubble structure in the laser field. As a result, the energy of the produced photons is substantially increased to the γ range. This new regime provides a path to generating high-charge electron beams and high-energy γ-ray sources.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"27 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79437509","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 effect of ablation on the nonlinear spike growth of single-mode ablative Rayleigh–Taylor instability (RTI) is studied by two-dimensional numerical simulations. It is shown that the ablation can reduce the quasi-constant velocity and significantly suppress the reacceleration of the spike in the nonlinear phase. It is also shown that the spike growth can affect the ablation-generated vorticity inside the bubble, which further affects the nonlinear bubble acceleration. The vorticity evolution is found to be correlated with the mixing width (i.e., the sum of the bubble and spike growths) for a given wave number and ablation velocity. By considering the effects of mass ablation and vorticity, an analytical model for the nonlinear bubble and spike growth of single-mode ablative RTI is developed in this study. It is found that the nonlinear growth of the mixing width, induced by the single mode, is dominated by the bubble growth for small-scale ablative RTI, whereas it is dominated by the spike growth for classical RTI.
{"title":"Effect of ablation on the nonlinear spike growth for the single-mode ablative Rayleigh–Taylor instability","authors":"J. Fu, H. Zhang, H. Cai, P. Yao, S. P. Zhu","doi":"10.1063/5.0106832","DOIUrl":"https://doi.org/10.1063/5.0106832","url":null,"abstract":"The effect of ablation on the nonlinear spike growth of single-mode ablative Rayleigh–Taylor instability (RTI) is studied by two-dimensional numerical simulations. It is shown that the ablation can reduce the quasi-constant velocity and significantly suppress the reacceleration of the spike in the nonlinear phase. It is also shown that the spike growth can affect the ablation-generated vorticity inside the bubble, which further affects the nonlinear bubble acceleration. The vorticity evolution is found to be correlated with the mixing width (i.e., the sum of the bubble and spike growths) for a given wave number and ablation velocity. By considering the effects of mass ablation and vorticity, an analytical model for the nonlinear bubble and spike growth of single-mode ablative RTI is developed in this study. It is found that the nonlinear growth of the mixing width, induced by the single mode, is dominated by the bubble growth for small-scale ablative RTI, whereas it is dominated by the spike growth for classical RTI.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"15 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79931242","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}
Zhijie Lu, X. Hou, F. Wan, Y. Salamin, C. Lv, Bo Zhang, Feijie Wang, Zhongxun Xu, Jian-Xing Li
The rapid development of ultrafast ultraintense laser technology continues to create opportunities for studying strong-field physics under extreme conditions. However, accurate determination of the spatial and temporal characteristics of a laser pulse is still a great challenge, especially when laser powers higher than hundreds of terawatts are involved. In this paper, by utilizing the radiative spin-flip effect, we find that the spin depolarization of an electron beam can be employed to diagnose characteristics of ultrafast ultraintense lasers with peak intensities around 1020–1022 W/cm2. With three shots, our machine-learning-assisted model can predict, simultaneously, the pulse duration, peak intensity, and focal radius of a focused Gaussian ultrafast ultraintense laser (in principle, the profile can be arbitrary) with relative errors of 0.1%–10%. The underlying physics and an alternative diagnosis method (without the assistance of machine learning) are revealed by the asymptotic approximation of the final spin degree of polarization. Our proposed scheme exhibits robustness and detection accuracy with respect to fluctuations in the electron beam parameters. Accurate measurements of ultrafast ultraintense laser parameters will lead to much higher precision in, for example, laser nuclear physics investigations and laboratory astrophysics studies. Robust machine learning techniques may also find applications in more general strong-field physics scenarios.
{"title":"Diagnosis of ultrafast ultraintense laser pulse characteristics by machine-learning-assisted electron spin","authors":"Zhijie Lu, X. Hou, F. Wan, Y. Salamin, C. Lv, Bo Zhang, Feijie Wang, Zhongxun Xu, Jian-Xing Li","doi":"10.1063/5.0140828","DOIUrl":"https://doi.org/10.1063/5.0140828","url":null,"abstract":"The rapid development of ultrafast ultraintense laser technology continues to create opportunities for studying strong-field physics under extreme conditions. However, accurate determination of the spatial and temporal characteristics of a laser pulse is still a great challenge, especially when laser powers higher than hundreds of terawatts are involved. In this paper, by utilizing the radiative spin-flip effect, we find that the spin depolarization of an electron beam can be employed to diagnose characteristics of ultrafast ultraintense lasers with peak intensities around 1020–1022 W/cm2. With three shots, our machine-learning-assisted model can predict, simultaneously, the pulse duration, peak intensity, and focal radius of a focused Gaussian ultrafast ultraintense laser (in principle, the profile can be arbitrary) with relative errors of 0.1%–10%. The underlying physics and an alternative diagnosis method (without the assistance of machine learning) are revealed by the asymptotic approximation of the final spin degree of polarization. Our proposed scheme exhibits robustness and detection accuracy with respect to fluctuations in the electron beam parameters. Accurate measurements of ultrafast ultraintense laser parameters will lead to much higher precision in, for example, laser nuclear physics investigations and laboratory astrophysics studies. Robust machine learning techniques may also find applications in more general strong-field physics scenarios.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"19 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74678941","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}
Yi Guo, Xiaomei Zhang, Dirui Xu, Xinju Guo, B. Shen, K. Lan
Laser–plasma instability (LPI) is one of the main obstacles to achieving predictable and reproducible fusion at high gain through laser-driven inertial confinement fusion (ICF). In this paper, for the first time, we show analytically and confirm with three-dimensional particle-in-cell simulations that angular incoherence provides suppression of the instability growth rate that is additional to and much stronger than that provided by the well-known temporal and spatial incoherence usually used in ICF studies. For the model used in our calculations, the maximum field ratio between the stimulated Raman scattering and the driving pulses drops from 0.2 for a Laguerre–Gaussian pulse with a single nonzero topological charge to 0.05 for a super light spring with an angular momentum spread and random relative phases. In particular, angular incoherence does not introduce extra undesirable hot electrons. This provides a novel method for suppressing LPI by using light with an angular momentum spread and paves the way towards a low-LPI laser system for inertial fusion energy with a super light spring of incoherence in all dimensions of time, space, and angle, and may open the door to the use of longer-wavelength lasers for inertial fusion energy.
{"title":"Suppression of stimulated Raman scattering by angularly incoherent light, towards a laser system of incoherence in all dimensions of time, space, and angle","authors":"Yi Guo, Xiaomei Zhang, Dirui Xu, Xinju Guo, B. Shen, K. Lan","doi":"10.1063/5.0136567","DOIUrl":"https://doi.org/10.1063/5.0136567","url":null,"abstract":"Laser–plasma instability (LPI) is one of the main obstacles to achieving predictable and reproducible fusion at high gain through laser-driven inertial confinement fusion (ICF). In this paper, for the first time, we show analytically and confirm with three-dimensional particle-in-cell simulations that angular incoherence provides suppression of the instability growth rate that is additional to and much stronger than that provided by the well-known temporal and spatial incoherence usually used in ICF studies. For the model used in our calculations, the maximum field ratio between the stimulated Raman scattering and the driving pulses drops from 0.2 for a Laguerre–Gaussian pulse with a single nonzero topological charge to 0.05 for a super light spring with an angular momentum spread and random relative phases. In particular, angular incoherence does not introduce extra undesirable hot electrons. This provides a novel method for suppressing LPI by using light with an angular momentum spread and paves the way towards a low-LPI laser system for inertial fusion energy with a super light spring of incoherence in all dimensions of time, space, and angle, and may open the door to the use of longer-wavelength lasers for inertial fusion energy.","PeriodicalId":54221,"journal":{"name":"Matter and Radiation at Extremes","volume":"9 1","pages":""},"PeriodicalIF":5.1,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82094842","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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