A paper on fusion neutron sources by a team from the United States of America's Lawrence Livermore National Laboratory and the University of Rochester has won the IAEA's annual Nuclear Fusion prize. The article describes critical successes in producing output from fusion in the form of neutrons.
The Nuclear Fusion prize is given annually to recognize outstanding work issued in the IAEA journal, Nuclear Fusion. Each year, a shortlist of ten papers is nominated. These are papers of the highest scientific standard, published in the journal volume three years previous to the award year. Nominations are based on citation record and recommendation by the Board of Editors. The Board then votes to determine which of these papers has made the largest scientific impact.
"Shooting really big lasers at stuff can stimulate fusion reactions like those occurring in the sun and other stars," said Charles B. Yeamans, the paper's first author and winner of the prize.
New Breakthroughs
The award-winning paper explores neutron sources from capsules filled with deuterium-tritium gas irradiated in a polar direct drive (PDD) geometry. These capsules are shot with robust laser pulses at ambient temperature to produce a fusion reaction. The winning paper may be accessed here.
Nuclear Fusion was launched in 1960 and is the most frequently cited journal in the field. It is co-published by the IAEA and the UK's Institute of Physics. Every major advance in fusion has been reflected in its pages. Since 2006, the journal prize has celebrated papers that make a significant contribution to their field. A shortlist of ten papers is nominated, based on citation record and recommendation by the Board of Editors. The Board then votes to determine which of these papers has made the largest scientific impact. Details of previous winning papers may be found here.
2024 winning paper: Inertial Confinement Fusion
The experiments detailed in the paper were carried out at Lawrence Livermore's National Laboratory (LLNL). For the last six decades, this laboratory, home to the world's most powerful laser, has worked to achieve the challenging goal of fusion ignition - producing more fusion energy than the amount of laser energy delivered to the target source. The lab's 'National Ignition Facility' (NIF) uses a method called inertial confinement fusion, which involves smashing a fuel pellet with lasers, as opposed to magnetic confinement fusion, which uses powerful magnets to trap a cloud of atoms, called plasma, in a reactor.
"For over a year and a half after the initial experimental success, […] polar direct drive was the most efficient way to convert laser energy input into fusion output," Yeamans said.
Heather Whitley, associate programme director for High Energy Density Science at LLNL, developed the initial design for a large diameter polar direct drive (PDD) capsule with Steve Craxton and Emma Garcia of the University of Rochester. She said: "The polar direct drive configuration provides excellent diagnostic access for other high temperature plasma physics experiments."
Following the PDD experiment, in December 2022 NIF conducted the first controlled fusion experiment to produce a net energy gain with the indirect drive method, a major scientific breakthrough which attracted global attention.
Yeaman's co-authors are Elijah Kemp, Zach Walters, Heather Whitley and Brent Blue from the Lawrence Livermore Nuclear Laboratory, and Steve Craxton, Patrick McKenty, Emma Garcia and Yujia Yang from the Laboratory for Laser Energetics at the University of Rochester.
The prize ceremony for the 2024 award and the upcoming 2025 award will take place in October during the IAEA Fusion Energy Conference in Chengdu China.
