Stellar Nuclear Fusion

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https://phys.org/news/2017-08-scientists-probe-conditions-stellar-interiors.html

Scientists probe the conditions of stellar interiors to measure nuclear reactions

August 7, 2017

Most of the nuclear reactions that drive the nucleosynthesis of the elements in our universe occur in very extreme stellar plasma conditions. This intense environment found in the deep interiors of stars has made it nearly impossible for scientists to perform nuclear measurements in these conditions - until now.

In a unique cross-disciplinary collaboration between the fields of plasma physics, nuclear astrophysics and laser fusion, a team of researchers including scientists from Lawrence Livermore National Laboratory (LLNL), Ohio University, the Massachusetts Institute of Technology (MIT) and Los Alamos National Laboratory (LANL), describe experiments performed in conditions like those of stellar interiors. The team's findings were published today by Nature Physics.

Read more at: https://phys.org/news/2017-08-scientists-probe-conditions-stellar-interiors.html#jCp
 

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http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys4220.html?foxtrotcallback=true

 

Thermonuclear reactions probed at stellar-core conditions with laser-based inertial-confinement fusion:

 

 

Abstract• 

Stars are giant thermonuclear plasma furnaces that slowly fuse the lighter elements in the universe into heavier elements, releasing energy, and generating the pressure required to prevent collapse. To understand stars, we must rely on nuclear reaction rate data obtained, up to now, under conditions very different from those of stellar cores. Here we show thermonuclear measurements of the 2H(d, n)3He and 3H(t,2n)4He S-factors at a range of densities (1.2–16 g cm−3) and temperatures (2.1–5.4 keV) that allow us to test the conditions of the hydrogen-burning phase of main-sequence stars. The relevant conditions are created using inertial-confinement fusion implosions at the National Ignition Facility. Our data agree within uncertainty with previous accelerator-based measurements and establish this approach for future experiments to measure other reactions and to test plasma-nuclear effects present in stellar interiors, such as plasma electron screening, directly in the environments where they occur.