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An artist's conception of the deuterium-tritium fusion. Image: Lawrence Livermore National Laboratory |
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Laboratory scientists
have taken a crucial step toward describing thermonuclear reactions from first
principles.
Over the past decade,
progress has been made in understanding the static properties of light nuclei
based on realistic interactions among protons and neutrons. But ab initio
calculations of nuclear scattering and reactions have been mostly confined to
systems of four nucleons or less.
Starting from a quantum
mechanical system of five point-like nucleons and their mutual interactions,
Petr Navrátil of the Nuclear Theory & Modeling Group (presently at TRIUMF
in Canada) and Sofia Quaglioni of the Computational Nuclear Physics Group in
the Physics Division, for the first time calculated within an ab initio
framework, the cross sections for the deuterium-tritium and deuterium-3He
fusion reactions.
The researchers found an
enhancement in the measured cross sections of both investigated reactions at
very low energy, due to the screening effects of electrons bound to the tritium
and, particularly 3He, targets (usually neutral atoms or molecules). This work
paves the way for improved evaluation of less known important cross sections
for fusion energy generation and nuclear plasma diagnostics.
Navrátril and Quaglioni
used a new approach for bound and scattering states of light nuclei developed
at the Lawrence Livermore National Laboratory (LLNL), thanks in part to a
Laboratory Directed Research and Development grant. The calculations required
for this effort were carried out under the LLNL Computing Grand Challenge
program.
The research will appear
in Physical Review Letters.
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