Recent experiments at the National Ignition Facility and theoretical modeling suggest that side stimulated Raman scattering(SSRS)instability could reduce laser–plasma coupling and generate considerable fluxes of supr...Recent experiments at the National Ignition Facility and theoretical modeling suggest that side stimulated Raman scattering(SSRS)instability could reduce laser–plasma coupling and generate considerable fluxes of suprathermal hot electrons under interaction conditions envisaged for direct-drive schemes for inertial confinement fusion.Nonetheless,SSRS remains to date one of the least understood parametric instabilities.Here,we report the first angularly and spectrally resolved measurements of scattered light at laser intensities relevant for the shock ignition scheme(I×10^(16)W/cm^(2)),showing significant SSRS growth in the direction perpendicular to the laser polarization.Modification of the focal spot shape and orientation,obtained by using two different random phase plates,and of the density gradient of the plasma,by utilizing exploding foil targets of different thicknesses,clearly reveals a different dependence of backward SRS(BSRS)and SSRS on experimental parameters.While convective BSRS scales with plasma density scale length,as expected by linear theory,the growth of SSRS depends on the spot extension in the direction perpendicular to laser polarization.Our analysis therefore demonstrates that under current experimental conditions,with density scale lengths L_(n)≈60–120μm and spot sizes FWHM≈40–100μm,SSRS is limited by laser beam size rather than by the density scale length of the plasma.展开更多
Fusion energy research is delivering impressive new results emerging from different infrastructures and industrial devices evolving rapidly from ideas to proof-of-principle demonstration and aiming at the conceptual d...Fusion energy research is delivering impressive new results emerging from different infrastructures and industrial devices evolving rapidly from ideas to proof-of-principle demonstration and aiming at the conceptual design of reactors for the production of electricity.A major milestone has recently been announced in laser fusion by the Lawrence Livermore National Laboratory and is giving new thrust to laser-fusion energy research worldwide.Here we discuss how these circumstances strongly suggest the need for a European intermediate-energy facility dedicated to the physics and technology of laser-fusion ignition,the physics of fusion materials and advanced technologies for high-repetitionrate,high-average-power broadband lasers.We believe that the participation of the broader scientific community and the increased engagement of industry,in partnership with research and academic institutions,make most timely the construction of this infrastructure of extreme scientific attractiveness.展开更多
This research work emphasizes the capability of delivering optically shaped targets through the interaction of nanosecond laser pulses with high-density gas-jet profiles,and explores proton acceleration in the near-cr...This research work emphasizes the capability of delivering optically shaped targets through the interaction of nanosecond laser pulses with high-density gas-jet profiles,and explores proton acceleration in the near-critical density regime via magnetic vortex acceleration(MVA).Multiple blast waves(BWs)are generated by laser pulses that compress the gas-jet into near-critical steep gradient slabs of a few micrometres thickness.Geometrical alternatives for delivering the laser pulses into the gas target are explored to efficiently control the characteristics of the density profile.The shock front collisions of the generated BWs are computationally studied by 3D magnetohydrodynamic simulations.The efficiency of the proposed target shaping method for MVA is demonstrated for TW-class lasers by a particle-in-cell simulation.展开更多
The rapid development of high-intensity laser-generated particle and photon secondary sources has attracted widespread interest during the last 20 years not only due to fundamental science research but also because of...The rapid development of high-intensity laser-generated particle and photon secondary sources has attracted widespread interest during the last 20 years not only due to fundamental science research but also because of the important applications of this developing technology.For instance,the generation of relativistic particle beams,betatron-type coherent X-ray radiation and high harmonic generation have attracted interest from various fields of science and technology owing to their diverse applications in biomedical,material science,energy,space,and security applications.In the field of biomedical applications in particular,laser-driven particle beams as well as laser-driven X-ray sources are a promising field of study.This article looks at the research being performed at the Institute of Plasma Physics and Lasers(IPPL)of the Hellenic Mediterranean University Research Centre.The recent installation of the ZEUS 45 TW laser system developed at IPPL offers unique opportunities for research in laser-driven particle and X-ray sources.This article provides information about the facility and describes initial experiments performed for establishing the baseline platforms for secondary plasma sources.展开更多
基金financial support from the LASERLAB-EUROPE Access to Research Infrastructure Activity (Application No. 23068)carried out within the framework of EUROfusion Enabling Research Projects AWP21-ENR-01-CEA02 and AWP24-ENR-IFE-02-CEA-02+3 种基金received funding from Euratom Research and Training Programme 2021–2025 under Grant No. 633053supported by the Ministry of Youth and Sports of the Czech Republic [Project No. LM2023068 (PALS RI)]by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDA25030200 and XDA25010100)supported by COST (European Cooperation in Science and Technology) through Action CA21128 PROBONO (PROton BOron Nuclear Fusion: from energy production to medical applicatiOns)
文摘Recent experiments at the National Ignition Facility and theoretical modeling suggest that side stimulated Raman scattering(SSRS)instability could reduce laser–plasma coupling and generate considerable fluxes of suprathermal hot electrons under interaction conditions envisaged for direct-drive schemes for inertial confinement fusion.Nonetheless,SSRS remains to date one of the least understood parametric instabilities.Here,we report the first angularly and spectrally resolved measurements of scattered light at laser intensities relevant for the shock ignition scheme(I×10^(16)W/cm^(2)),showing significant SSRS growth in the direction perpendicular to the laser polarization.Modification of the focal spot shape and orientation,obtained by using two different random phase plates,and of the density gradient of the plasma,by utilizing exploding foil targets of different thicknesses,clearly reveals a different dependence of backward SRS(BSRS)and SSRS on experimental parameters.While convective BSRS scales with plasma density scale length,as expected by linear theory,the growth of SSRS depends on the spot extension in the direction perpendicular to laser polarization.Our analysis therefore demonstrates that under current experimental conditions,with density scale lengths L_(n)≈60–120μm and spot sizes FWHM≈40–100μm,SSRS is limited by laser beam size rather than by the density scale length of the plasma.
文摘Fusion energy research is delivering impressive new results emerging from different infrastructures and industrial devices evolving rapidly from ideas to proof-of-principle demonstration and aiming at the conceptual design of reactors for the production of electricity.A major milestone has recently been announced in laser fusion by the Lawrence Livermore National Laboratory and is giving new thrust to laser-fusion energy research worldwide.Here we discuss how these circumstances strongly suggest the need for a European intermediate-energy facility dedicated to the physics and technology of laser-fusion ignition,the physics of fusion materials and advanced technologies for high-repetitionrate,high-average-power broadband lasers.We believe that the participation of the broader scientific community and the increased engagement of industry,in partnership with research and academic institutions,make most timely the construction of this infrastructure of extreme scientific attractiveness.
基金The authors acknowledge support of this work by the project‘ELI-LASERLAB Europe Synergy,HiPER&IPERIONCH.gr’(MIS 5002735),which is implemented under the action‘Reinforcement of the Research and Innovation Infrastructure’,funded by the Operational programme‘Competitiveness,Entrepreneurship and Innovation’(NSRF 2014-2020)and co-financed by Greece and the European Union(European Regional Development Fund)supported by computational time granted by the Greek Research and Technology Network(GRNET)in the National HPC facility-ARIS-under project ID pr011027-LaMPIOS+1 种基金This work has been carried out within the framework of the EUROfusion Consortium,funded by the European Union via the Euratom Research and Training Programme(grant agreement No.101052200-EUROfusion)the Hellenic National Program of Controlled Thermonuclear Fusion.
文摘This research work emphasizes the capability of delivering optically shaped targets through the interaction of nanosecond laser pulses with high-density gas-jet profiles,and explores proton acceleration in the near-critical density regime via magnetic vortex acceleration(MVA).Multiple blast waves(BWs)are generated by laser pulses that compress the gas-jet into near-critical steep gradient slabs of a few micrometres thickness.Geometrical alternatives for delivering the laser pulses into the gas target are explored to efficiently control the characteristics of the density profile.The shock front collisions of the generated BWs are computationally studied by 3D magnetohydrodynamic simulations.The efficiency of the proposed target shaping method for MVA is demonstrated for TW-class lasers by a particle-in-cell simulation.
基金support of this work by the project‘ELI-LASERLAB Europe Synergy,Hi PER&IPERIONCH.gr’(MIS 5002735)which is implemented under the Action‘Reinforcement of the Research and Innovation Infrastructure’funded by the Operational Programme‘Competitiveness,Entrepreneurship and Innovation’(NSRF 2014–2020)+2 种基金co-financed by Greece and the European Union(European Regional Development Fund)supported by computational time granted from the Greek Research and Technology Network(GRNET)in the National HPC facility,ARIS,under project ID pr009023-La MIPla S IIIcofinanced by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness,Entrepreneurship,and Innovation,under the call Research–Create–Innovate(project code:T1EDK-04549,project title:Development of a coherent X-ray multispectral microscopy system)。
文摘The rapid development of high-intensity laser-generated particle and photon secondary sources has attracted widespread interest during the last 20 years not only due to fundamental science research but also because of the important applications of this developing technology.For instance,the generation of relativistic particle beams,betatron-type coherent X-ray radiation and high harmonic generation have attracted interest from various fields of science and technology owing to their diverse applications in biomedical,material science,energy,space,and security applications.In the field of biomedical applications in particular,laser-driven particle beams as well as laser-driven X-ray sources are a promising field of study.This article looks at the research being performed at the Institute of Plasma Physics and Lasers(IPPL)of the Hellenic Mediterranean University Research Centre.The recent installation of the ZEUS 45 TW laser system developed at IPPL offers unique opportunities for research in laser-driven particle and X-ray sources.This article provides information about the facility and describes initial experiments performed for establishing the baseline platforms for secondary plasma sources.
