The experiment took place at the National Ignition Facility (NIF). Image Credit: Lawrence Livermore National Laboratory
While most astronomers are turning their attention to Sun’s surface in preparation for the coming Great American Eclipse, another team of researchers has been looking much deeper – at the very heart of a star.
A new technique has allowed astrophysicists to recreate the conditions within a stellar core and study the nuclear reactions that allow stars to shine.
The researchers, made up of a team of plasma physicists, nuclear astrophysicists and laser fusion experts, recreated the conditions using capsules of gas.
At the Lawrence Lievermore National Laboratory (LLNL), the team were able to implode these capsules, heating the gas to millions of degrees Kelvin and compressing them to extremely high densities, allowing the fusion reactions that happen in a stellar core, known as nucleosynthesis, to occur.
“Ordinarily, these kinds of nuclear astrophysics experiments are performed on [particle] accelerator experiments in the laboratory, which become particularly challenging at the low energies often relevant for nucleosynthesis,” says Dan Casey, an astrophysicist from LLNL who took part in the study.
Particle accelerators are better tuned to dealing with higher energy reactions, meaning that at lower energies there are far fewer reactions occurring, and it is much more difficult to see the signal over the noise from both terrestrial and cosmic sources.
However, the results found using the new method did match with previous accelerator experiments.
“Perhaps most importantly, this work lays groundwork for potential experimental tests of phenomena that can only be found in the extreme plasma conditions of stellar interiors,” says Casey
Now that the team know it is possible to recreate such reactions, they will push the technique to explore other nuclear reactions, and gain a fuller understanding of what happens deep in the heart of a star.