Ignition is needed to make fusion energy a viable alternative energy source, but has yet to be achieved1. A key step on the way to ignition is to have the energy generated through fusion reactions in an inertially confined fusion plasma exceed the amount of energy deposited into the deuterium–tritium fusion fuel and hotspot during the implosion process, resulting in a fuel gain greater than unity. Here we report the achievement of fusion fuel gains exceeding unity on the US National Ignition Facility using a ‘high-foot’ implosion method2,3, which is a manipulation of the laser pulse shape in a way that reduces instability in the implosion. These experiments show an order-of-magnitude improvement in yield performance over past deuterium–tritium implosion experiments. We also see a significant contribution to the yield from α-particle self-heating and evidence for the ‘bootstrapping’ required to accelerate the deuterium–tritium fusion burn to eventually ‘run away’ and ignite.
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Edwards, M. J. et al. Progress towards ignition on the National Ignition Facility. Phys. Plasmas 20, 070501 (2013)
Dittrich, T. R. et al. Design of a high-foot/high-adiabat ICF capsule for the National Ignition Facility. Phys. Rev. Lett. 112, LJ14108 (2014)
Park, H.-S. et al. High-adiabat, high-foot, inertial confinement fusion implosion experiments on the National Ignition Facility. Phys. Rev. Lett. 112, LK13998 (2014)
Lindl, J. D. & Moses, E. I. Plans for the National Ignition Campaign (NIC) on the National Ignition Facility (NIF): on the threshold of initiating ignition experiments. Phys. Plasmas 18, 050901 (2011)
Glenzer, S. H. et al. Cryogenic thermonuclear fuel implosions on the National Ignition Facility. Phys. Plasmas 19, 056318 (2012)
Bodner, S. E. Rayleigh-Taylor instability and laser-pellet fusion. Phys. Rev. Lett. 33, 761–764 (1974)
Gonchorov, V. N. & Hurricane, O. A. Panel 3 Report: Implosion Hydrodynamics. Report LLNL-TR-562104 (Lawrence Livermore National Laboratory, 2012)
Ma, T. et al. Onset of hydrodynamic mix in high-velocity, highly compressed inertial confinement fusion implosions. Phys. Rev. Lett. 111, 085004 (2013)
Regan, S. P. et al. Hot-spot mix in ignition-scale inertial confinement fusion targets. Phys. Rev. Lett. 111, 045001 (2013)
Betti, R., Goncharov, V. N., McCrory, R. L. & Verdon, C. P. Growth rates of the Rayleigh-Taylor instability in inertial confinement fusion. Phys. Plasmas 5, 1446–1454 (1998)
Lindl, J. Development of the indirect-drive approach to inertial confinement fusion and the target physics basis for ignition and gain. Phys. Plasmas 2, 3933–4024 (1995)
Haan, S. et al. Point design targets, specifications, and requirements for the 2010 ignition campaign on the National Ignition Facility. Phys. Plasmas 18, 051001 (2011)
Michel, P. et al. Tuning the implosion symmetry of ICF targets via controlled crossed-beam energy transfer. Phys. Rev. Lett. 102, 025004 (2009)
Michel, P. et al. Symmetry tuning via controlled crossed-beam energy transfer on the National Ignition Facility. Phys. Plasmas 17, 056305 (2010)
Moody, J. D. et al. Multistep redirection by cross-beam power transfer of ultrahigh-power lasers in a plasma. Nature Phys. 8, 344–349 (2012)
Callahan, D. A. et al. The velocity campaign for ignition on NIF. Phys. Plasmas 19, 056305 (2012)
Marinak, M. M. et al. Three-dimensional HYDRA simulations of National Ignition Facility targets. Phys. Plasmas 8, 2275 (2001)
Kozioziemski, B. J. et al. Deuterium-tritium layer formation for the National Ignition Facility. Fusion Sci. Technol. 59, 14–25 (2011)
Glebov, V. & Yu et al. Development of nuclear diagnostics for the National Ignition Facility. Rev. Sci. Instrum. 77, 10E715 (2006)
Bleuel, D. L. et al. Neutron activation diagnostics at the National Ignition Facility. Rev. Sci. Instrum. 83, 10D313 (2012)
Gatu Johnson, M. et al. Neutron spectrometry – an essential tool for diagnosing implosions at the National Ignition Facility. Rev. Sci. Instrum. 83, 10D308 (2012)
Bosch, H.-S. & Hale, G. M. Improved formulas for fusion cross-section and thermal reactivities. Nucl. Fusion 32, 611–631 (1992)
Krokhin, O. N. & Rozanov, V. B. Escape of α-particles from a laser-pulse-initiated thermonuclear reaction. Sov. J. Quantum Electron. 2, 393–394 (1973)
Atzeni, S. & Meyer-ter-Vehn, J. The Physics of Inertial Fusion 32 398 (Oxford Univ. Press, 2004)
Patel, P. et al. Performance of DT layered implosions on the NIF. Bull. Am. Phys. Soc. 58, abstr. NO4.00001. (2013)
Cerjan, C., Springer, P. T. & Sepke, S. M. Integrated diagnostic analysis of inertial confinement fusion capsule performance. Phys. Plasmas 20, 056319 (2013)
Zimmerman, G. B. & Kruer, W. L. Numerical Simulation of laser initiated fusion. Comments Plasma Phys. Control. Fusion 2, 85–89 (1975)
Betti, R. et al. Thermonuclear ignition in inertial confinement fusion and comparison with magnetic confinement. Phys. Plasmas 17, 058102 (2010)
Goncharov, V. N. et al. Improved performance of direct-drive ICF target designs with adiabat shaping using an intense picket. Phys. Plasmas 10, 1906–1918 (2003)
We thank P. Albright, J. Atherton, L. R. Benedetti, D. Bradley, J. A. Caggiano, R. Dylla-Spears, M. J. Edwards, W. H. Goldstein, B. Goodwin, S. Haan, A. Hamza, W. Hsing, P. Kervin, J. Kilkenny, B. Kozioziemski, O. Landen, J. Lindl, B. MacGowan, A. Mackinnon, N. Meezan, J. F. Meeker, J. Moody, E. Moses, D. Pilkington, T. Parham, J. Ralph, S. Ross, H. Robey, R. Rygg, B. Spears, R. Town, C. Verdon, A. Wan and B. Van Wonterghem, and the NIF operations, cryogenics and targets teams. We also thank V. Goncharov and J. Knauer for their advice, and R. Betti for bringing our attention to equation (3). Thanks also go to NIF’s external collaborators at GA (targets), LLE (diagnostics), the MIT Plasma Science and Fusion Center (magnetic recoil spectrometer diagnostic), CEA and AWE. This work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under contract no. DE-AC52-07NA27344.
The authors declare no competing financial interests.
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Hurricane, O., Callahan, D., Casey, D. et al. Fuel gain exceeding unity in an inertially confined fusion implosion. Nature 506, 343–348 (2014) doi:10.1038/nature13008
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