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

Cristoforetti, G.; Koester, P.; S., Atzeni,; D., Batani,; Fujioka, S.; Hironaka, Y.; Hüller, S.; Idesaka, T.; Katagiri, K.; Kawasaki, K.; R., Kodama,; Mancelli, D.; Nicolaï, Ph.; Ozaki, N.; Schiavi, A.; Shigemori, K.; Takizawa, R.; Tamagawa, T.; Tanaka, D.; Tentori, A.; Umeda, Y.; Yogo, A.; Gizzi, L.A.

doi:10.1017/hpl.2023.13

Cited by 7 publications

(3 citation statements)

References 40 publications

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“…A reliable description of the above parametric instabilities is a key issue in Inertial Confinement Fusion (ICF) 4,5 , since both the light scattered from the plasma and the hot electrons can account for several tens of percent of incident laser energy, therefore affecting significantly the evolution and the energy balance of plasma hydrodynamics and producing a larger energy requirement for the laser driver. Moreover, these mechanisms may exhibit a collective behaviour through the concomitant action of several overlapping laser beams [6][7][8] , which can affect the energy balance of the different beams and result in an asymmetric compression of the fuel capsule. Furthermore, in direct-drive ICF schemes 9 , HE can preheat the uncompressed fuel, enhancing its entropy and preventing its ignition.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the origin of hot electrons in laser plasma interaction at shock ignition intensities

Cristoforetti

Baffigi

Batani

et al. 2023

Preprint

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Shock Ignition is a two-step scheme to reach Inertial Confinement Fusion, where the precompressed fuel capsule is ignited by a strong shock driven by an intense laser pulse at intensity ∼ 1016 W/cm2. In this report we detail the results of an experiment designed to investigate the origin of hot electrons (HE) in laser-plasma interaction at intensities and plasma temperatures expected for Shock Ignition. A detailed time- and spectrally-resolved characterization of Stimulated Raman Scattering (SRS) and Two Plasmon Decay (TPD) instabilities, as well as of the generated HE, suggest that SRS is the dominant source of HE via the damping of daughter plasma waves. The temperature dependence of laser plasma instabilities was also investigated, enabled by the use of different ablator materials, suggesting that TPD is damped at earlier times for higher plasma temperatures, due to the Landau damping effect. The identification of the predominant HE source and the effect of plasma temperature on laser plasma interaction, here investigated, are extremely useful for developing the mitigation strategies for reducing the impact of HE on the fuel ignition.

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Section: Introductionmentioning

confidence: 99%

Investigation on the origin of hot electrons in laser plasma interaction at shock ignition intensities

Cristoforetti

Baffigi

Batani

et al. 2023

Preprint

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“…8 Institute of Plasma Physics and Lasers, Hellenic Mediterranean University Research Centre, Rethymnon, Greece. 9 Department of Electronic Engineering, Hellenic Mediterranean University, Chania, Greece. 10 GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany.…”

mentioning

confidence: 99%

“…A reliable description of the above parametric instabilities is a key issue in inertial confinement fusion 5,6 , since both the light scattered from the plasma and the hot electrons can account for several tens of percent of incident laser energy, therefore affecting significantly the evolution and the energy balance of plasma hydrodynamics and producing a larger energy requirement for the laser driver. Moreover, these mechanisms may exhibit a collective behaviour through the concomitant action of several overlapping laser beams [7][8][9] , which can affect the energy balance of the different beams and result in an asymmetric compression of the fuel capsule. Furthermore, in directdrive schemes 10 for inertial confinement fusion, HE can preheat the uncompressed fuel, enhancing its entropy and preventing its ignition.…”

mentioning

confidence: 99%

Investigation on the origin of hot electrons in laser plasma interaction at shock ignition intensities

Cristoforetti,

Baffigi,

Batani

et al. 2023

Sci Rep

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Shock Ignition is a two-step scheme to reach Inertial Confinement Fusion, where the precompressed fuel capsule is ignited by a strong shock driven by a laser pulse at an intensity in the order of $$10^{16}$$ 10 16 W/cm$$^2$$ 2 . In this report we describe the results of an experiment carried out at PALS laser facility designed to investigate the origin of hot electrons in laser-plasma interaction at intensities and plasma temperatures expected for Shock Ignition. A detailed time- and spectrally-resolved characterization of Stimulated Raman Scattering and Two Plasmon Decay instabilities, as well as of the generated hot electrons, suggest that Stimulated Raman Scattering is the dominant source of hot electrons via the damping of daughter plasma waves. The temperature dependence of laser plasma instabilities was also investigated, enabled by the use of different ablator materials, suggesting that Two Plasmon Decay is damped at earlier times for higher plasma temperatures, accompanied by an earlier ignition of SRS. The identification of the predominant hot electron source and the effect of plasma temperature on laser plasma interaction, here investigated, are extremely useful for developing the mitigation strategies for reducing the impact of hot electrons on the fuel ignition.

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Hot electron preheat in hydrodynamically scaled direct-drive inertial confinement fusion implosions on the NIF and OMEGA

et al. 2023

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Hot electron preheat has been quantified in warm, directly driven inertial confinement fusion implosions on OMEGA and the National Ignition Facility (NIF), to support hydrodynamic scaling studies. These CH-shell experiments were designed to be hydrodynamically equivalent, spanning a factor of 40 in laser energy and a factor of 3.4 in spatial and temporal scales, while preserving the incident laser intensity of 1015 W/cm2. Experiments with similarly low levels of beam smoothing on OMEGA and NIF show a similar fraction (∼0.2%) of laser energy deposited as hot electron preheat in the unablated shell on both OMEGA and NIF and similar preheat per mass (∼2 kJ/mg), despite the NIF experiments generating a factor of three more hot electrons (∼1.5% of laser energy) than on OMEGA (∼0.5% of laser energy). This is plausibly explained by more absorption of hot electron energy in the ablated CH plasma on NIF due to larger areal density, as well as a smaller solid angle of the imploding shell as viewed from the hot electron generating region due to the hot electrons being produced at a larger standoff distance in lower-density regions by stimulated Raman scattering, in contrast to in higher-density regions by two-plasmon decay on OMEGA. The results indicate that for warm implosions at intensities of around 1015 W/cm2, hydrodynamic equivalence is not violated by hot electron preheat, though for cryogenic implosions, the reduced attenuation of hot electrons in deuterium–tritium plasma will have to be considered.

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

Cited by 7 publications

References 40 publications

Investigation on the origin of hot electrons in laser plasma interaction at shock ignition intensities

Investigation on the origin of hot electrons in laser plasma interaction at shock ignition intensities

Investigation on the origin of hot electrons in laser plasma interaction at shock ignition intensities

Hot electron preheat in hydrodynamically scaled direct-drive inertial confinement fusion implosions on the NIF and OMEGA

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