First measurements of p11B fusion in a magnetically confined plasma

The fusion reaction involving proton (p) and boron (11B) has unique advantages over deuterium-tritium (DT) fusion in terms of number of neutrons generated and availability of the fuel components. Here the authors demonstrate the (p,11B) fusion reaction in a magnetically confined plasma at the Large Helical Device. Proton-boron (p(11)B) fusion is an attractive potential energy source but technically challenging to implement. Developing techniques to realize its potential requires first developing the experimental capability to produce p(11)B fusion in the magnetically-confined, thermonuclear plasma environment. Here we report clear experimental measurements supported by simulation of p(11)B fusion with high-energy neutral beams and boron powder injection in a high-temperature fusion plasma (the Large Helical Device) that have resulted in diagnostically significant levels of alpha particle emission. The injection of boron powder into the plasma edge results in boron accumulation in the core. Three 2 MW, 160 kV hydrogen neutral beam injectors create a large population of well-confined, high -energy protons to react with the boron plasma. The fusion products, MeV alpha particles, are measured with a custom designed particle detector which gives a fusion rate in very good relative agreement with calculations of the global rate. This is the first such realization of p(11)B fusion in a magnetically confined plasma.

Automated summary

The authors demonstrate the proton-boron (p(11)B) fusion reaction in a magnetically confined plasma at the Large Helical Device, which has advantages over deuterium-tritium (DT) fusion in terms of neutron generation and fuel availability. This realization of p(11)B fusion is technically challenging but important for developing techniques to harness its potential as an energy source. Experimental measurements and simulations using high-energy neutral beams and boron powder injection in a high-temperature fusion plasma show significant levels of alpha particle emission, marking the first successful realization of p(11)B fusion in a magnetically confined plasma.