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Visualizing fast electron energy transport into laser-compressed high-density fast-ignition targets


Recent progress in kilojoule-scale high-intensity lasers has opened up new areas of research in radiography, laboratory astrophysics, high-energy-density physics, and fast-ignition (FI) laser fusion. FI requires efficient heating of pre-compressed high-density fuel by an intense relativistic electron beam produced from laser–matter interaction. Understanding the details of electron beam generation and transport is crucial for FI. Here we report on the first visualization of fast electron spatial energy deposition in a laser-compressed cone-in-shell FI target, facilitated by doping the shell with copper and imaging the K-shell radiation. Multi-scale simulations accompanying the experiments clearly show the location of fast electrons and reveal key parameters affecting energy coupling. The approach provides a more direct way to infer energy coupling and guide experimental designs that significantly improve the laser-to-core coupling to 7%. Our findings lay the groundwork for further improving efficiency, with 15% energy coupling predicted in FI experiments using an existing megajoule-scale laser driver.

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Figure 1: Configuration of the target, experimental layout, and laser parameters.
Figure 2: Experimentally measured and simulated Cu Kα images.
Figure 3: Spectrally measured Cu Kα yield as a function of OMEGA-EP short-pulse energy.
Figure 4: Dependence of fast electron energy-coupling efficiency on core areal density and electron beam temperature.


  1. Moses, E. Ignition on the National Ignition Facility: a path towards inertial fusion energy. Nucl. Fusion 49, 104022 (2009).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  5. Atzeni, S. et al. Fast ignitor target studies for the HiPER project. Phys. Plasmas 15, 056311 (2008).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  8. Arikawa, Y. et al. A experimental study on the energy coupling efficiency from the heating laser to core plasma in the fast ignition experiment. Bull. Am. Phys. Soc. 58, BAPS.2013.DPP.YO5.1 (2013).

    Google Scholar 

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

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  11. Stoeckl, C. et al. A spherical crystal imager for OMEGA EP. Rev. Sci. Instrum. 83, 033107 (2012).

    Article  ADS  Google Scholar 

  12. Marinak, M., Haan, S., Dittrich, T., Tipton, R. & Zimmerman, G. A comparison of three-dimensional multimode hydrodynamic instability growth on various National Ignition Facility capsule designs with HYDRA simulations. Phys. Plasmas 5, 1125–1132 (1998).

    Article  ADS  Google Scholar 

  13. Radha, P. et al. Multidimensional analysis of direct-drive, plastic-shell implosions on OMEGA. Phys. Plasmas 12, 056307 (2005).

    Article  ADS  Google Scholar 

  14. Akli, K. et al. Temperature sensitivity of Cu Kα imaging efficiency using a spherical Bragg reflecting crystal. Phys. Plasmas 14, 023102 (2007).

    Article  ADS  Google Scholar 

  15. Pérez, F., Kemp, A., Divol, L., Chen, C. & Patel, P. Deflection of MeV electrons by self-generated magnetic fields in intense laser-solid interactions. Phys. Rev. Lett. 111, 245001 (2013).

    Article  ADS  Google Scholar 

  16. Solodov, A. & Betti, R. Stopping power and range of energetic electrons in dense plasmas of fast-ignition fusion targets. Phys. Plasmas 15, 042707 (2008).

    Article  ADS  Google Scholar 

  17. Solodov, A. A. et al. Simulations of fuel assembly and fast-electron transport in integrated fast-ignition experiments on OMEGA. Bull. Am. Phys. Soc. 58, BAPS.2013.DPP.YO5.3 (2013).

    Google Scholar 

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

    Article  ADS  Google Scholar 

  19. Robinson, A., Key, M. & Tabak, M. Focusing of relativistic electrons in dense plasma using a resistivity-gradient-generated magnetic switchyard. Phys. Rev. Lett. 108, 125004 (2012).

    Article  ADS  Google Scholar 

  20. Chawla, S. et al. Effect of target material on fast-electron transport and resistive collimation. Phys. Rev. Lett. 110, 025001 (2013).

    Article  ADS  Google Scholar 

  21. Larson, D., Tabak, M. & Ma, T. Hybrid simulations for magnetized fast ignition targets and analyzing cone-wire experiments. Bull. Am. Phys. Soc. 55, BAPS.2010.DPP.JP9.119 (2010).

    Google Scholar 

  22. Jarrott, L. C. et al. Fast electron transport and spatial energy deposition in Cu-doped fast ignition plasmas. Bull. Am. Phys. Soc. 59, BAPS.2014.DPP.CI1.4 (2014).

    Google Scholar 

  23. 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).

    Article  ADS  Google Scholar 

  24. Crane, J. et al. Journal of Physics: Conference Series Vol. 244, 032003 (IOP Publishing, 2010).

    Google Scholar 

  25. McGuffey, C. et al. 9th Int. Conf. Inertial Fusion Sci. Appl. Vol. 9, 181 (2015).

    Google Scholar 

  26. Ivancic, S. et al. Channeling of multikilojoule high-intensity laser beams in an inhomogeneous plasma. Phys. Rev. E 91, 051101 (2015).

    Article  ADS  Google Scholar 

  27. Welch, D., Rose, D., Cuneo, M., Campbell, R. & Mehlhorn, T. Integrated simulation of the generation and transport of proton beams from laser-target interaction. Phys. Plasmas 13, 063105 (2006).

    Article  ADS  Google Scholar 

  28. Qiao, B. et al. Fast electron generation and transport from ten-picosecond laser-plasma interactions in the cone-guided fast ignition. Bull. Am. Phys. Soc. 58, BAPS.2013.DPP.YO5.5 (2013).

    Google Scholar 

  29. MacFarlane, J., Golovkin, I., Wang, P., Woodruff, P. & Pereyra, N. Spect3d—a multi-dimensional collisional-radiative code for generating diagnostic signatures based on hydrodynamics and pic simulation output. High Energy Density Phys. 3, 181–190 (2007).

    Article  ADS  Google Scholar 

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This material is based on work supported by the US Department of Energy National Nuclear Security Administration under the National Laser User Facility programme with Award Number DE-NA0000854, DE-NA0002033, the OFES Fusion Science Center (FSC) grant No DE-FC02-04ER54789, the OFES ACE Fast Ignition grant No. DE-FG02-95ER54839, and NNSA cooperative agreement DE-NA0001944. The support of the DOE does not constitute an endorsement by the DOE of the views expressed in this article. J.J.S. participated in this work thanks to funding from the French National Agency for Research (ANR) and the competitiveness cluster Alpha—Route des Lasers through project TERRE ANR-2011-BS04-014. The authors would like to acknowledge excellent support provided by the Omega Laser Facility staff and the GA target fabrication group. The authors are thankful to S. Chawla for HYDRA simulations and C. Dorrer for the measured OMEGA-EP pre-pulse information.

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Authors and Affiliations



F.N.B. and M.S.W. designed and executed the experiment as principal investigators with help from L.C.J., C.McGuffey, W.T., A.A.S., R.B., J.D., M.H.K., F.J.M., H.S.M., P.K.P., J.J.S., H.S., T.Y. and R.B.S.; C.S., H.C., T.D., V.Y.G., H.H., T.I. and C.Mileham developed and operated diagnostics; data analysis was performed by L.C.J., C.McGuffey and W.T.; simulations were performed by A.A.S. for the DRACO/LSP modelling, B.Q. for the LSP PIC modelling, L.C.J. for the ZUMA modelling; targets were manufactured by E.M.G., R.W.L. and R.B.S.; M.S.W., C.McGuffey and F.N.B. led the writing of the manuscript with significant contributions from A.A.S., L.C.J., W.T., H.S.M. and R.B.S.; figures were prepared by L.C.J., A.A.S. and M.S.W.

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Correspondence to M. S. Wei or F. N. Beg.

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The authors declare no competing financial interests.

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

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