Enhanced energy coupling for indirect-drive fast-ignition fusion targets

Abstract

One of the most promising approaches to reach a high gain in inertial confinement fusion is the fast ignition scheme. In this scheme, a relativistic electron beam is generated; this passes through the imploded plasma and deposits parts of its energy in the core. However, the large angular spread of the relativistic electron beam and the poorly controlled compression of the target affect realization of the fast ignition technique. Here, we demonstrate that indirectly driven (that is, driven by X-rays generated inside a gold hohlraum) implosions with a ‘high-foot’ and a short-coast time of less than 200 ps allow us to tightly compress the shell. Furthermore, we show the ability to optimize the symmetry of the imploding shell by changing the hohlraum length, successfully tuning a suitable tube-shaped shell to compensate for the large angular spread of the relativistic electron beam and to enhance the electron-to-core coupling efficiency via resistive magnetic fields. Benefiting from those experimental techniques, a significant enhancement in neutron yield was achieved in our indirectly driven fast ignition experiments. These results pave the way towards high-coupling fast ignition experiments with indirectly driven targets similar to those at the National Ignition Facility.

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Fig. 1: Schematic of an indirect-drive fast ignition experiment.
Fig. 2: Laser pulse shape and flow diagrams.
Fig. 3: Fusion yield and REB spectrum.
Fig. 4: Imploding shell at peak compression time.

Data availability

Data supporting the findings of this study are available from the authors upon reasonable request. Source data for Figs. 2 and 3 are available with the paper.

Change history

  • 06 May 2020

    An amendment to this paper has been published and can be accessed via a link at the top of the paper.

References

  1. 1.

    Hurricane, O. A. et al. Fuel gain exceeding unity in an inertially confined fusion implosion. Nature 506, 343–348 (2014).

    ADS  Article  Google Scholar 

  2. 2.

    Lindl, J. et al. Review of the national ignition campaign 2009–2012. Phys. Plasmas 21, 020501 (2014).

    ADS  Article  Google Scholar 

  3. 3.

    Tabak, M. et al. Ignition and high gain with ultrapowerful lasers. Phys. Plasmas 1, 1626–1634 (1994).

    ADS  Article  Google Scholar 

  4. 4.

    Betti, R. et al. Shock ignition of thermonuclear fuel with high areal density. Phys. Rev. Lett. 98, 155001 (2007).

    ADS  Article  Google Scholar 

  5. 5.

    Kodama, R. et al. Fast heating of ultrahigh-density plasma as a step towards laser fusion ignition. Nature 412, 798–802 (2001).

    ADS  Article  Google Scholar 

  6. 6.

    Kodama, R. et al. Nuclear fusion: fast heating scalable to laser fusion ignition. Nature 418, 933–934 (2002).

    ADS  Article  Google Scholar 

  7. 7.

    Shiraga, H. et al. Integrated experiments of fast ignition targets by GEKKO-XII and LFEX lasers. High Energy Density Phys. 8, 227–230 (2012).

    ADS  Article  Google Scholar 

  8. 8.

    Sakata, S. et al. Magnetized fast isochoric laser heating for efficient creation of ultra-high-energy-density states. Nat. Commun. 9, 3937 (2018).

    ADS  Article  Google Scholar 

  9. 9.

    Kitagawa, Y. et al. Direct heating of a laser-imploded core by ultraintense laser-driven ions. Phys. Rev. Lett. 114, 195002 (2015).

    ADS  Article  Google Scholar 

  10. 10.

    Gong, T. et al. Direct observation of imploded core heating via fast electrons with super-penetration scheme. Nat. Commun. 10, 5614 (2019).

    ADS  Article  Google Scholar 

  11. 11.

    Theobald, W. et al. Initial cone-in-shell fast-ignition experiments on OMEGA. Phys. Plasmas 18, 056305 (2011).

    ADS  Article  Google Scholar 

  12. 12.

    Theobald, W. et al. Time-resolved compression of a capsule with a cone to high density for fast-ignition laser fusion. Nat. Commun. 5, 5785 (2014).

    ADS  Article  Google Scholar 

  13. 13.

    Jarrott, L. C. et al. Visualizing fast electron energy transport into laser compressed high-density fast ignition targets. Nat. Phys. 12, 499–504 (2016).

    Article  Google Scholar 

  14. 14.

    Stephens, R. B. et al. Implosion of indirectly driven reentrant-cone shell target. Phys. Rev. Lett. 91, 185001 (2003).

    ADS  Article  Google Scholar 

  15. 15.

    Zhang, F. et al. Measurement of the injecting time of picosecond laser in indirect-drive integrated fast ignition experiments using an X-ray streak camera. Rev. Sci. Instrum. 90, 033504 (2019).

    ADS  Article  Google Scholar 

  16. 16.

    Shan, L. Q. et al. Experimental evidence of kinetic effects in indirect-drive inertial confinement fusion hohlraum. Phys. Rev. Lett. 120, 195001 (2018).

    ADS  Article  Google Scholar 

  17. 17.

    Perez, F. et al. Magnetically guided fast electrons in cylindrically compressed matter. Phys. Rev. Lett. 107, 065004 (2011).

    ADS  Article  Google Scholar 

  18. 18.

    Nakamura, H. et al. Fast heating of cylindrically imploded plasmas by petawatt laser light. Phys. Rev. Lett. 100, 165001 (2008).

    ADS  Article  Google Scholar 

  19. 19.

    Remington, B. A. et al. Rayleigh–Taylor instabilities in high-energy density settings on the national ignition facility. Proc. Natl Acad. Sci. USA 116, 18233–18238 (2019).

    ADS  Article  Google Scholar 

  20. 20.

    Hurricane, O. A. et al. On the importance of minimizing ‘coast-time’ in X-ray driven inertially confined fusion implosions. Phys. Plasmas 24, 092706 (2017).

    ADS  Article  Google Scholar 

  21. 21.

    Betti, R. & Hurricane, O. A. Inertial-confinement fusion with lasers. Nat. Phys. 12, 435–448 (2016).

    Article  Google Scholar 

  22. 22.

    Saillard, Y. Acceleration and decceleration model of indirect drive ICF capsules. Nuclear Fusion 46, 1017–1035 (2006).

    ADS  Article  Google Scholar 

  23. 23.

    Pei, W. B. The construction of simulation algorithms for laser fusion. Commun. Comput. Phys. 2, 255–270 (2007).

    Google Scholar 

  24. 24.

    Cai, H. B. et al. Enhancing the number of high-energy electrons deposited to a compressed pellet via double cones in fast ignition. Phys. Rev. Lett. 102, 245001 (2009).

    ADS  Article  Google Scholar 

  25. 25.

    Xu, H. et al. Control of fast electron propagation in foam target by high-Z doping. Plasma Phys. Control. Fusion 61, 025010 (2019).

    ADS  Article  Google Scholar 

  26. 26.

    Park, H. S. et al. High-adiabat high-foot inertial confinement fusion implosion experiments on the national ignition facility. Phys. Rev. Lett. 112, 055001 (2014).

    ADS  Article  Google Scholar 

  27. 27.

    Zhu, J. Q. et al. Status and development of high-power laser facilities at the NLHPLP. High Power Laser Sci. Eng. 6, e55 (2018).

    Article  Google Scholar 

  28. 28.

    He, S. K. et al. Generation of ultrahigh-velocity collisionless electrostatic shocks using an ultra-intense laser pulse interacting with foil-gas target. Chin. Phys. Lett. 36, 105201 (2019).

    ADS  Article  Google Scholar 

  29. 29.

    He, X. T. et al. Physical studies of fast ignition in China. Plasma Phys. Control. Fusion 57, 064003 (2015).

    ADS  Article  Google Scholar 

  30. 30.

    Strozzi, D. J. et al. Fast-ignition transport studies: realistic electron source, integrated particle-in-cell and hydrodynamic modeling, imposed magnetic fields. Phys. Plasmas 19, 072711 (2012).

    ADS  Article  Google Scholar 

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Acknowledgements

We thank all the SG-IIU technical staff at Shanghai Institute of Optics and Fine Mechanics for their support during the experiment. The research leading to these results has received funding from the Science Challenge Project, no. TZ2016005, the National Key Programme for S&T Research and Development (grant no. 2016YFA0401100), the National Natural Science Foundation of China (grants nos. 11975055, 11805182 and U1730449 (NSAF)). PIC and hybrid-PIC simulations were performed on the Tianhe-2 supercomputer (China).

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Contributions

Y.Q.G., S.P.Z., C.T.Z., K.D., Y.K.D., B.H.Z., W.Y.Z. and X.T.H. conceived this project, which was designed by F.Z., H.B.C., W.M.Z., C.T.Z., S.P.Z., Y.Q.G. and B.H.Z. The SG-IIU experiment was carried out by F.Z., W.M.Z., L.Q.S., J.B.C., Q.T., H.J.L., L.W., D.X.L., Y.M.Y., H.B.D., B.B., J.L., F.L., B.Z., L.Z., M.H.Y., Z.H.Y., W.W.W., B.C., L.Y., W.Q., C.T., Z.Q.Y., H.B.C., S.Z.W., H.Z., J.F.W., G.L.R. and L.F.C. The paper was written by H.B.C. and F.Z. The data were analysed by H.B.C. and F.Z. Numerical simulations were performed by H.B.C., Z.S.D., H.X., F.J.G., J.F.G., H.S.Z., W.S.Z., M.Q.H., L.H.C., W.D.Z. and S.Y.Z.

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Correspondence to H. B. Cai or Y. Q. Gu or S. P. Zhu.

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The authors declare no competing interests.

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Supplementary information

Supplementary Information

Supplementary discussion and Figs. 1–4.

Source data

Source Data Fig. 2

High-foot and low-foot laser pulse.

Source Data Fig. 3

Neutron yield, measured and simulated electron spectrum.

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Zhang, F., Cai, H.B., Zhou, W.M. et al. Enhanced energy coupling for indirect-drive fast-ignition fusion targets. Nat. Phys. 16, 810–814 (2020). https://doi.org/10.1038/s41567-020-0878-9

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