Compression and electron beam heating of solid target under the external magnetic field for fast ignition

Nagatomo, Hideo; Johzaki, Tomoyuki; Asahina, Takashi; Hata, Masayuki; Matsuo, Kazuki; Lee, S.; Sunahara, A.; Sakagami, Hiroyuki; Mima, K.; Iwano, Keisuke; Fujioka, Shinsuke; Shiraga, H.; Azechi, H.

doi:10.1088/1741-4326/aa74f0

Cited by 9 publications

(4 citation statements)

References 17 publications

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“…To optimize the whole process of fast ignition, integrated simulation is necessary, including the simulation of the heating process with the PIC simulation [13]. For the heating process, applying an external magnetic field to guide the electron beam is also being considered [14][15][16][17][18]. In that case, it is necessary to consider the influence of the external magnetic field on the implosion dynamics.…”

Section: Discussionmentioning

confidence: 99%

Improvement of ignition and burning target design for fast ignition scheme

et al. 2021

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For the fast ignition scheme of laser fusion, a highly compressed fuel core is necessary using a cone-inserted spherical solid target. We design an optimal compression method with a multistep laser pulse shape using a 2D radiation hydrodynamics simulation. In the design, the maximum areal density is ρR max = 0.46 g cm−2 with 8 kJ of implosion laser. Considering the scaling law of hydrodynamic, we obtained 82 kJ and 1.3 MJ for the ignition-scale-target (ρR max = 1.1 g cm−2) and burning-scale-target (ρR max = 2.5 g cm−2), respectively. In a preliminary study of hydrodynamic instability in the optimized cone-inserted implosion, there is no significant growth of the instabilities that affect the implosion performance. A parameter search to investigate the feasibility and robustness of a high areal density design for changes in the laser pulse shape is performed. As a result, a delay of several tens of pico-second of the rising laser pulse is acceptable.

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Section: Discussionmentioning

confidence: 99%

Improvement of ignition and burning target design for fast ignition scheme

et al. 2021

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“…That is, the highly compressed fuel core profiles at the maximum ρR time will be the initial conditions of the kinetic simulations for the next heating process, where generation of energetic electrons due to the nonlinear relativistic LPI, transport and absorption of the energetic electrons processes will be simulated [22]. An external magnetic field [23,24] is effective for improving the heating efficiency because it reduces the divergence angle of the energetic electrons [25,26]. It will be taken account in the next design study.…”

Section: Design Factor Dependent On Heating Processmentioning

confidence: 99%

Study of fast ignition target design for ignition and burning experiments

et al. 2019

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For the fast ignition of laser fusion, a reliable target design is required for an ignition scale target. This paper shows the first optimized target design for the implosion phase of fast ignition, which is scalable to larger targets. The requirements from the heating process are taken account. In conclusion, a target can be highly compressed using multi-step laser pulse irradiation to a solid spherical target with an inserted gold cone. In an 8 kJ scale implosion, the maximum areal density of deuterium-tritium fuel reaches 0.39 g cm −2 according to 2D simulation results, which is 62% of the case without the cone. Based on the similarity rule, we estimate that the requirement of the implosion laser energy for ignition scale targets (ρR max =1.0 g cm −2 ) is 135 kJ.

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“…The key issue with this scheme is that the relativistic electron beams, as produced inside the cone, are strongly diverging (with half-angles potentially reaching 50°). Various methods to control this divergence (self-collimation by self-generated magnetic fields, guiding thanks to adequate target manufacturing, sequential irradiation, double cone geometry, etc) have been proposed [39] but, according to simulations, the most efficient one seems to be the use of external kilo-Tesla-class magnetic fields [40,41].…”

Section: Fimentioning

confidence: 99%