An international scientific collaboration using the PALS laser facility in Prague has reported a major advance in hydrogen-boron (pB11) fusion. The report, published in January in Physical Review E, demonstrated a 40-fold increase in fusion yield over previous experiments at the same facility in 2014. Researchers hit a target of boron nitride with some embedded hydrogen with a 2 TW burst of infrared laser radiation, focused down to an 80-micron spot. The research team explained that they achieved the 40-fold increase in fusion yield simply by making the target thicker. The advance is both a step forward for hydrogen-boron fusion, which has the potential to provide cheap, totally clean energy, and an example of the sort of leaps that can occur in fusion research.
The laser approach to pB11 fusion is being promoted by Australian company HB11 Energy, although that company was not involved in the PALS experiment. The main disadvantage of this approach relative to Focus Fusion using the plasma focus device is the very low efficiency of the laser needed to initiate the fusion. The iodine laser at PALS, for example, needs 1.2 MJ input to produce a 600 J laser pulse. The fusion output from the latest experiment was 0.06 J, so the critical ratio of output energy to input energy is still about 80 times less than that achieved by LPPFusion’s FF-1, using a much less reactive fuel, deuterium. To reach net energy, HB11 Energy envisions fusion generators that would be much larger and more costly than will be needed for Focus Fusion. Despite these drawbacks to the approach, the data obtained in the PALS laser experiments is extremely encouraging to all those, including LPPFusion, working toward pB11-based energy generation.