Development of an experimental platform for the investigation of laser-plasma interaction in conditions relevant to shock ignition regime

The shock ignition (SI) approach to inertial confinement fusion is a promising scheme for achieving energy production by nuclear fusion. SI relies on using a high intensity laser pulse (≈1016 W/cm2, with a duration of several hundred ps) at the end of the fuel compression stage. However, during laser-plasma interaction (LPI), several parametric instabilities, such as stimulated Raman scattering and two plasmon decay, nonlinearly generate hot electrons (HEs). The whole behavior of HE under SI conditions, including their generation, transport, and final absorption, is still unclear and needs further experimental investigation. This paper focuses on the development of an experimental platform for SI-related experiments, which simultaneously makes use of multiple diagnostics to characterize LPI and HE generation, transport, and energy deposition. Such diagnostics include optical spectrometers, streaked optical shadowgraph, an x-ray pinhole camera, a two-dimensional x-ray imager, a Cu Kα line spectrometer, two hot-electron spectrometers, a hard x-ray (bremsstrahlung) detector, and a streaked optical pyrometer. Diagnostics successfully operated simultaneously in single-shot mode, revealing the features of HEs under SI-relevant conditions.T. Tamagawa, Y. Hironaka, K. Kawasaki, D. Tanaka, T. Idesaka, N. Ozaki, R. Kodama, R. Takizawa, S. Fujioka, A. Yogo, D. Batani, Ph. Nicolai, G. Cristoforetti, P. Koester, L. A. Gizzi, and K. Shigemori, "Development of an experimental platform for the investigation of laser–plasma interaction in conditions relevant to shock ignition regime", Review of Scientific Instruments 93, 063505 (2022) https://doi.org/10.1063/5.008996

Multibeam Laser Plasma Interaction at Gekko XII laser facility in conditions relevant for Direct-Drive Inertial Confinement Fusion

International audienceLaser Plasma Interaction and hot electrons have been characterized in detail in laser irradiation conditions relevant for direct-drive Inertial Confinement F usion. T he e xperiment h as b een carried out at Gekko XII laser facility in multibeam planar geometry at intensity ∼ 3 • 10 15 W/cm 2. Experimental data suggest that high-energy electrons, with temperature 20-50 keV and conversion efficiencies η < 1% , we re ma inly pr oduced by th e da mping of el ectron pl asma wa ves dr iven by Two Plasmon Decay. Stimulated Raman Scattering is observed in a near-threshold growth regime, producing a reflectivity o f ∼ 0 .01%, a nd i s w ell d escribed b y a n a nalytical m odel a ccounting 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

Multibeam laser plasma interaction at Gekko XII laser facility in conditions relevant for direct-drive inertial confinement fusion

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 3 × 10^15 W/cm^2 . Experimental data suggest that high-energy electrons, with temperatures of 20–50 keV and conversion efficiencies of η &lt; 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. direct-drive inertial confinement fusion. The experiment was carried out at the Gekko XII laser facility in multibeam 15 2 planar target geometry at an intensity of approximately 3 × 10 W/cm^2 . Experimental data suggest that high-energy electrons, with temperatures of 20–50 keV and conversion efficiencies of η &lt; 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

Multibeam Laser Plasma Interaction at Gekko XII laser facility in conditions relevant for Direct-Drive Inertial Confinement Fusion

International audienceLaser Plasma Interaction and hot electrons have been characterized in detail in laser irradiation conditions relevant for direct-drive Inertial Confinement F usion. T he e xperiment h as b een carried out at Gekko XII laser facility in multibeam planar geometry at intensity ∼ 3 • 10 15 W/cm 2. Experimental data suggest that high-energy electrons, with temperature 20-50 keV and conversion efficiencies η < 1% , we re ma inly pr oduced by th e da mping of el ectron pl asma wa ves dr iven by Two Plasmon Decay. Stimulated Raman Scattering is observed in a near-threshold growth regime, producing a reflectivity o f ∼ 0 .01%, a nd i s w ell d escribed b y a n a nalytical m odel a ccounting 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