HB11 Energy’s mission is to realize large-scale electricity generation from the fusion of hydrogen with boron-11 (the HB11, or “proton-boron”, reaction) without the environmental problems normally associated with nuclear energy. A non-thermal approach is taken in the initiation of the reaction using high-peak-power lasers, which was the pursuit of HB11 Energy founder Prof. Heinrich Hora’s career as a theoretical physicist. In the 1980s, the invention of Chirped Pulse Amplification (CPA) of laser pulses by Donna Strickland and Gerard Mourou (Nobel Prize 2018) enabled the possibility of experimentally validating the earlier theoretical predictions. Several experimental demonstrations of the HB11 reaction using CPA lasers inspired the establishment of HB11 Energy and with it, the possibility of realizing an aneutronic nuclear energy source with easily accessible and safe fuel resources that could last thousands of years. Like all quests for fusion energy, there are significant scientific challenges remaining. HB11 Energy Holdings Pty Ltd, an Australian company, was established as the best vehicle to co-ordinate a global collaborative research effort to address these challenges and build capacity to host large-scale public private partnerships, such as those now recommended by the US National Academies of Science, Engineering and Medicine (NASEM) (US National Academies of Sciences, Engineering and Medicine in Bringing Fusion to the U.S. Grid,: National Academies Press, Washington, D.C, 2021). If net-energy-gain can be achieved through HB11 Energy’s concepts, there are many engineering benefits over traditional DT fusion that will see a dramatically simpler and safer reactor being produced. A technoeconomic assessment of such a reactor is also discussed which presents many engineering challenges that will need to be met before commercial HB11 fusion can be deployed on a large-scale.

The Lawson criterion for proton-boron (p-¹¹B) thermonuclear fusion is substantially higher than that for deuterium-tritium (DT) because the fusion cross section is lower and peaks at higher ion energies. The Maxwellian averaged p-¹¹B reactivity peaks at several hundred keV, where bremsstrahlung radiation emission may dominate over fusion reactions if electrons and ions are in thermal equilibrium and the losses are unrestricted. Nonequilibrium burn has often been suggested to realize the benefits of this aneutronic reaction, but the predominance of elastic scattering over fusion reactivity makes this difficult to achieve. The development of ultrashort pulse lasers (USPL) has opened new possibilities for initiating nonequilibrium thermonuclear burns and significant numbers of p-¹¹B alpha particles have been reported from several experiments. We present an analysis that shows that these significant alpha yields are the result of beam fusion reactions that do not scale to net energy gain. We further find that the yields can be explained by experimental parameters and recently updated cross sections such that a postulated avalanche mechanism is not required. We use this analysis to understand the underlying physics of USPL-driven nonequilibrium fusion reactions and whether they can be used to initiate fusion burns. We conclude by outlining a path to increasing the p-¹¹B reactivity towards the goal of achieving ignition and describing the design principles that we will use to develop a computational point design.

Shortly after the laser was invented in 1960, scientists sought to use it for thermonuclear fusion. By 1963, Livermore had a classified laser inertial confinement fusion (ICF) program and leaders predicted scientific breakeven by 1973. In 1974, KMS Fusion, Inc. announced thermonuclear neutrons from a laser target and promised grid electricity within 10 years. Private capital was attracted, but the data fell far short of the optimistic simulations. Magnetic fusion energy has had civilian funding (DOE), while ICF has primarily received military funding (DOE Defense Programs and now NNSA). As bigger lasers have been built and better simulations performed, optimism about ICF breakeven has waxed and waned. The achievement of ignition and gain on NIF has validated ICF's scientific basis, and the DOE and venture capital funded private companies are again interested in inertial fusion energy (IFE). The new DOE Milestone-Based Fusion Development Program is creating public–private partnerships to accelerate progress toward fusion pilot plants. ARPA-E, DOE INFUSE, and DOE IFE STAR are also building a U.S. IFE program within DOE. The U.S. leads in ICF, but developing IFE is an international competition. Private companies are leading the way. HB11 Energy Pty Ltd. is pursuing the aneutronic proton–boron fuel cycle. Xcimer Energy is developing a disruptive IFE technology to achieve high laser energies at dramatically lower costs. This 50-year perspective discusses where the U.S. IFE program is headed and promising strategies for progress in establishing an effective U.S. IFE program from both public and private perspectives.

Short-pulse, ultrahigh-intensity lasers have opened new regimes for studying fusion plasmas and creating novel ultrashort ion beams and neutron sources. Diagnosing the plasma in these experiments is important for optimizing the fusion yield but difficult due to the picosecond time scales, 10 s of micron-cubed volumes, and high densities. We propose to use the yields of photons and neutrons produced by parallel reactions involving the same reactants to diagnose the plasma conditions and predict the yields of specific reactions of interest. In this work, we focus on verifying the yield of the high-interest aneutronic proton-boron fusion reaction 11Bp,2α4He , which is difficult to measure directly due to the short stopping range of the produced αs in most materials. We identify promising photon-producing reactions for this purpose and compute the ratios of the photon yield to the α yield as a function of plasma parameters. In beam-fusion experiments, the ¹¹C yield is an easily-measurable observable to verify the α yield. In light of our results, improving and extending measurements of the cross-sections for these parallel reactions are important steps to gain greater control over these laser-driven fusion plasmas.