For Scientists

HB11’s concept is radically different to all current commercial fusion approaches and will not share any of the major challenges as DT fusion. It is also drastically simpler, and therefore will be cheaper and much faster to develop. 

From a scientific standpoint, the few experiments that have been performed on HB11 laser fusion have demonstrated landmark results and have placed HB11 as the most likely candidate to realise safe, practical and economically viable energy generation. Three of these landmark results are described below.

Non-thermal fusion of HB11 – The first “landmark” result is that these laser-initiated fusion reactions have been demonstrated in several papers by Belyaev (2005), Labaune, Picciotto, Margarone and Giuffrida. “Plasma block ignition” was discovered numerically as a phenomenon that is responsible for the reactions  by non-thermal means. This means that HB11 fusion can be achieved without heating a sample to very high temperatures, the need for which has posed multiple challenges to current fusion approaches with DT or DD fusion and will most likely deem all of them economically unviable. This provides validation that the HB11 reaction is possible, and that it can be achieved via non-thermal means using CPA laser pulses.

High HB11 reaction gains – The second “landmark” result extended from the observation that these HB11 reaction gains are many orders of magnitude higher than expected. In particular the results of

Picciotto and Margarone achieved one billion times higher reaction yields than expected. This was subsequently explained as an “avalanche” or chain reactionThis result is significant as it opens the possibility that HB11 fusion will be able to produce a net energy gain.

The first and second landmark discoveries describe what we want to achieve by the irradiation of “Laser 2” (Figure 2) on the sample to achieve the reaction. 

High magnetic fields – The third “Landmark” result was achieved in 2013 with the first demonstration that kilo-Tesla magnetic fields using lasers and a capacitive coil. In the HB11 concept, “Laser 1” (Figure 2) is used with a coil to produce this ultra-high magnetic field as “Laser 2” ignites the reaction. The purpose of combining the HB11 reaction (laser 2) within this high magnetic field (laser 1) is that the plasma is best trapped within the cylindrical sample allowing the accelerated hydrogen ions the highest probability of interacting with and fusing to a boron atom. This scenario would achieve the highest number of HB11 reactions and therefore highest net energy gain. This experiment would represent the final stage of the Scientific proof-of-concept.

Beyond these demonstrations, little research has investigated the various aspects of non-thermal fusion, HB11 fusion, high magnetic fields, nor has it tried to optimise the parameters of the laser, fuel, or capacitive coils to maximised reaction gains.

What is HB11 Energy’s Concept?

The laser boron fusion concept reactor is detailed in the “Roadmap” paper authored by many of the representatives of this submission. It includes sections on “Problems to be solved” and “Need for very high contrast ratio PW-PS laser pulses.” Below is a summary of this concept.  

The HB11 reactor concept is shown in Fig. 1. (A) Shows a sphere at least one-meter in radius and intended to capture energy from the generation of helium nuclei produced by the HB11 reaction – 2.9 MeV alpha particles representing about 300 kWh energy per shot of 15mg HB11 fuel. The sphere has to be made of steel or similar material of at least a few millimetres in thickness to absorb the shock produced by the fusion reaction, which will correspond to about that of 50 grams of chemical

Fig. 1. (A, left) Schematic of an electric power generator including sphere (grey) and hydrogen-boron fusion reactor unit at the centre (B). (B, right) The reaction unit includes capacitor coils (yellow) around the HB11 fuel pellet (purple).

The reactor unit is shown in Fig. 1 (B). The HB11 fuel sits inside a capacitor coil in the reaction unit. A kilotesla magnetic field is produced by a nanosecond pulse in Laser 1 by means described by Fujioka et al. 12  and Santos et al.. Simultaneously, a kilojoule picosecond pulse in Laser 2 creates the conditions for the ultrahigh acceleration of plasma blocks required for non-thermal ignition of HB11. These conditions were predicted numerically by Prof Hora in 1977 to achieve the HB11 reaction (literature summarised in).  Several more recent results have not only observed the HB11 reaction experimentally but also an avalanche reaction realising gains much higher than predicted for spherical compression (summarised by H. Hora, G. Korn, S. Eliezer, G. Miley, Mourou, et al. in 2015). 

The reactor is intended to achieve the direct conversion of nuclear energy into electricity without its conversion into heat. This is possible only if plasma discharge losses between the unit equipped with Faraday screening and the reactor wall (sphere) can be sufficiently reduced, eliminating any significant heating of the wall material. To achieve this, the reactor sphere will be charged at a potential of less than but close to 1.4 megavolts allowing it to slow the charged alpha particles

before they contact the sphere. The alpha-particles will be neutralised on contact with the sphere allowing their charge to be captured as the source of electricity.

While there will undoubtedly be challenges with the conversion of this charge into AC electricity suitable for a power grid, the concept removes the requirement of heat exchange and steam turbine infrastructure allowing for much smaller and cost-effective generators to be produced. 

 

What still needs to be done?

In achieving this experimental proof-of-concept, some of the key streams of research that will need to be explored include:

  • Further understanding block ignition from radiation pressure laser drivers. Research around radiation pressure, bulk acceleration and the generation of plasma blocks, is in its infancy. With the dawn of 10 PW laser interactions approaching, we expect a surge in activity within the laser plasma community towards high energy high efficiency radiation pressure acceleration and we are poised to steer this towards realizing HB11 reactions. The long-term aim of this stream of experiments will be to use the currently available (and soon to be online) laser systems to confirm plane geometry picosecond block ignition using hydrogen boron fuel and optimize the laser conditions in order to achieve the largest gains in a fusion reaction. 
  • Understanding the laser requirements – Laser development over the next decade such as those driven by advances for the European ELI project, and others, should enable this capability to be developed. Lasers with performance of ~10 PW and rep-rates of a shot a minute are examples of the ongoing rapid development of the field.
  • Understanding the kilotesla magnetic field –  The physics of laser generation of the ultrahigh magnetic fields in the coils is also an active field of research (e.g. Fujioka et al. [10]). Additional and ongoing research on the field properties, the time dependence, and further improvements are of technology is also required to evaluate and optimize this concept.

Reactor sphere – a better understanding of the operations / physics of the reactor sphere will provide a critical step in understanding future scientific and engineering design parameters for building a reactor.  For instance, placement of the reaction unit at the centre of the reaction sphere is a challenge and is similar to the need of all inertially confined approaches.

  • Fuel – A better understanding of the ideal fuel and the construction and characteristics of the target will be required in order to achieve the most efficient interaction and the highest gain fusion reaction.

Computation modelling – All experimental efforts will be supported by the efforts of a computational modelling team.

 Agency, I.E., World Energy Investment 2018, I.E. Agency, Editor. 2018.

https://www.iea.org/reports/world-energy-investment-2018

 Belyaev, V., et al., Observation of neutronless fusion reactions in picosecond laser plasmas. Physical review. E, Statistical, nonlinear, and soft matter physics, 2005. 72: p. 026406.

https://doi.org/10.1103/PhysRevE.72.026406

 

 Labaune, C., et al., Laser-initiated primary and secondary nuclear reactions in Boron-Nitride. Scientific Reports, 2016. 6: p. 21202.

https://www.nature.com/articles/srep21202

 Picciotto, A., et al., Boron-Proton Nuclear-Fusion Enhancement Induced in Boron-Doped Silicon Targets by Low-Contrast Pulsed Laser. Physical Review X, 2014. 4: p. 031030.

https://doi.org/10.1103/PhysRevX.4.031030

 

 Margarone, D., et al., Advanced scheme for high-yield laser driven nuclear reactions. Plasma Physics and Controlled Fusion, 2014. 57(1): p. 014030

https://iopscience.iop.org/article/10.1088/0741-3335/57/1/014030

 Giuffrida, et. al. (2020). High-current stream of energetic α particles from laser-driven proton-boron fusion. PHYSICAL REVIEW E 101, 013204

https://doi.org/10.1103/PhysRevE.101.013204

 

  Eliezer, S., et al., Avalanche proton-boron fusion based on elastic nuclear collisions Physics of Plasmas, 2016. 23(5).

https://doi.org/10.1063/1.4950824

 Picciotto, A., et al., Boron-Proton Nuclear-Fusion Enhancement Induced in Boron-Doped Silicon Targets by Low-Contrast Pulsed Laser. Physical Review X, 2014. 4: p. 031030.

https://journals.aps.org/prx/abstract/10.1103/PhysRevX.4.031030

 Margarone, D., et al., Advanced scheme for high-yield laser driven nuclear reactions. Plasma Physics and Controlled Fusion, 2014. 57(1): p. 014030

https://iopscience.iop.org/article/10.1088/0741-3335/57/1/014030

 Hora, H., et al., Fusion energy using avalanche increased boron reactions for block-ignition by ultrahigh power picosecond laser pulses. Laser and Particle Beams, 2015. 33(4): p. 607-619.

https://doi.org/10.1017/S0263034615000634

 Fujioka, S., et al., Kilotesla Magnetic Field due to a Capacitor-Coil Target Driven by High Power Laser. Scientific Reports, 2013. 3: p. 1170.

https://www.nature.com/articles/srep01170

 Hora, H., et al., Road map to clean energy using laser beam ignition of boron-hydrogen fusion. Laser and Particle Beams, 2017. 35(4): p. 730-740.

https://doi.org/10.1017/S0263034617000799

 Santos, J.J., et al., Laser-driven platform for generation and characterization of strong quasi-static magnetic fields. New Journal of Physics, 2015. 17(8): p. 083051.

https://iopscience.iop.org/article/10.1088/1367-2630/17/8/083051

 

 Hora, H., Laser Plasma Physics, in Laser Plasma Physics, SPIE, Editor. 2016. p. p. 247

https://spie.org/Publications/Book/2073373?SSO=1

 

 Hora, H., et al., Fusion energy using avalanche increased boron reactions for block-ignition by ultrahigh power picosecond laser pulses. Laser and Particle Beams, 2015. 33(4): p. 607-619.

https://doi.org/10.1017/S0263034615000634

 Fujioka, S., et al., Kilotesla Magnetic Field due to a Capacitor-Coil Target Driven by High Power Laser. Scientific Reports, 2013. 3: p. 1170.

https://www.nature.com/articles/srep01170