Scientists at TRIUMF, the Institut de Physique Nucléaire, and Lawrence Livermore National Laboratory have for the first time accurately predicted the properties of polarized deuterium-tritium thermonuclear fusion. Their findings, described in a Nature Communications publication released today, add to our current understanding of the dynamics of nuclear fusion and may enable more accurate predictions of other thermonuclear reactions critical to nuclear science applications.
In polarized nuclear fusion, the two reactants are ‘spinning’ in the same direction within the reaction plasma before fusion. This alignment can drastically impact the dynamics of the fusion reaction; in the studied reaction in particular it can lead to a 50% enhanced reaction rate for polarized reactants vs. non-polarized reactants.
In this study, detailed in the paper 'Ab initio predictions for polarized deuterium-tritium thermonuclear fusion', the team focused on the spin-polarized fusion of deuterium (D) and tritium (T), two “heavy” hydrogen isotopes. Using ab initio calculations (a ground-up methodology which describes atomic nuclei from basic interactions of their constituents, protons and neutrons), researchers were able to solve DT’s five-body reaction problem (two nucleons from deuterium, three from tritium) and accurately predict the properties of the emitted reaction products, the neutron and 4He.
Due to its high reaction rate and a significant energy release (17.6 MeV per reaction), the D+T->n+4He process is studied in large-scale experiments in facilities such as NIF (at LLNL) and ITER (in France) as a potential future energy source. Detailed understanding of the dynamics of DT fusion and other light-ion reactions is important for the success of these experiments as well as for the modeling of astrophysics processes responsible for the production of elements in the Universe. Mainly due to energy restraints, it is very difficult to mimic and study fusion reactions in the laboratory. To supplement experimental evidence, researchers turn to nuclear theory and ab initio studies like the one detailed in this paper.
“Polarized DT fusion is extremely difficult to investigate experimentally due to the low counting rates at energies of interest. Theoretical calculations such as we have done then complement experiments. Analogous calculations could be used in the future to improve the predictivity of astrophysics simulations,” said TRIUMF physicist Petr Navratil, one of the authors of the paper.
The team was comprised of Guillaume Hupin (Institut de Physique Nucléaire), Sofia Quaglioni (Lawrence Livermore National Laboratory) and Petr Navrátil of TRIUMF. Congratulations to Petr and the entire research team!