Three peer-reviewed papers highlight scientific results of National Ignition Facility record yield shot

Three papers highlight results of record-breaking 1.3 MJ yield experiment

physical review letter and two in Physical Review E. This stylized image shows the cryogenic targets used in these record-setting inertial fusion experiments. Credit: James Wickbold/LLNL “width=”800” height=”457″/>

On the first anniversary of LLNL’s National Ignition Facility achieving more than 1.3 megajoules of production, the scientific results of this record-breaking experiment have been published in three peer-reviewed papers: one in physical review letter and two in Physical Review E. This stylized image shows the cryogenic targets used in these record-setting inertial fusion experiments. Credit: James Wick Bolt/LLNL

After decades of inertial confinement fusion research, Lawrence Livermore National Laboratory (LLNL)’s National Ignition Facility (NIF) achieved production of more than 1.3 megajoules (MJ) for the first time on August 8, 2021, enabling research The personnel are at the critical point of fusion gain, enabling scientific ignition.


On the first anniversary of this historic achievement, the scientific results of this record-breaking experiment have been published in three peer-reviewed papers: one in physical review letter and two in Physical Review E. Over 1,000 authors are included in one of physical review letter This paper honors and thanks the many individuals who have worked for decades to achieve this major advance.

“The record-breaking footage is a major scientific advance in fusion research and demonstrates that fusion ignition in the laboratory is possible at NIF,” said Omar Hurricane, chief scientist of LLNL’s inertial confinement fusion program. Conditioning has been a long-standing goal of all inertial confinement fusion research and opens up a new experimental mechanism in which alpha particle self-heating exceeds all cooling mechanisms in fusion plasmas.”

The papers detail the August 8, 2021 results and associated design, refinement, and experimental measurements. LLNL physicist Alex Zylstra, lead experimenter and first author of the experiment Physical Review E The paper notes that in 2020 and early 2021, the lab conducted experiments in a “burning plasma” state for the first time, setting the stage for record-setting shots.

“From that design, we made several improvements to achieve the August 8, 2021 shooting,” he said. “Both physical design and target quality improvements helped lead to the success of the August shooting, which was Physical Review E document. “

This experiment incorporates several changes, including an improved target design. “Reduced glide time through a more efficient cavity compared to previous experiments is the key to moving between burning plasma and ignition states,” said LLNL physicist Anne Kricher, lead design of the other paper teacher and first author Physical Review E Paper. “Other major changes are improved capsule mass and smaller fuel fill tubes.”

Three peer-reviewed papers highlight scientific results of record output at national ignition facility

This three-part image shows the profile feature target geometry (a), which includes the gold-coated depleted uranium cavity surrounding the HDC capsule, with some features marked. The capsule, about 2 mm in diameter, is located in the center of a cavity about 1 cm high and occupies only a small fraction of the volume. The laser beam enters the target from top and bottom apertures, called the laser entry apertures. In (b), the total laser power (blue) versus time and simulated full-cavity radiation temperature for the August 8, 2021 experiment is shown, with some key elements marked. All images are 100 square microns. The imaging data is used to reconstruct the hot spot plasma volume needed to infer pressure and other plasma properties.Image credit: Lawrence Livermore National Laboratory

Since the experiment last August, the team has been conducting a series of experiments to try to replicate the performance and understand the experimental sensitivity of this new mechanism.

“Many variables affect each experiment,” Kricher said. “The 192 laser beams didn’t behave exactly the same on every shot, the mass of the targets varied, and the ice layer grew on each target with a different roughness. These experiments provided an opportunity to test and understand this New, sensitive experimental regimes for intrinsic variability.”

While repeated attempts did not achieve the same level of fusion yield as the August 2021 experiment, all of them demonstrated capsule gains greater than unity, with yields in the 430-700 kJ range, significantly higher than the peak yield of 170 kJ prior to February 2021. From The data obtained in these and other experiments provided key clues about what was right and what changes were needed to repeat the experiment and surpass its performance in the future. The team also used experimental data to further understand the fundamental processes of fusion ignition and combustion, and enhanced simulation tools to support inventory management.

Going forward, the team is working to use the accumulated experimental data and simulations to move towards a more robust state — further beyond the ignition cliff — where the general trends found in this new experimental state can be better aligned with the availability of targets and laser performance. Transgender distinguish.

Efforts to improve fusion performance and robustness are further improving energy transfer to the hot spot through improved lasers, improved targeting, and modified designs, while maintaining or even increasing hot spot pressure. This includes ways to improve the compression of fusion fuels, increase the amount of fuel, and more.

“Having a ‘proof-of-existence’ ignition in the lab is very exciting,” Hurricane said. “We operate in a regime that no researcher has been in since the end of the nuclear test, and as we continue to make progress, this A great opportunity to expand our knowledge.”


Researchers at the edge of fusion ignition at National Ignition Facility


More information:
H. Abu-Shawareb et al., Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment, physical review letter (2022). DOI: 10.1103/PhysRevLett.129.075001

AB Zylstra et al., Experimental Achievements and Ignition Characteristics at the National Ignition Facility, Physical Review E (2022). DOI: 10.1103/PhysRevE.106.025202

AL Kritcher et al, Design of Inertial Fusion Experiments Beyond Lawson Ignition Criteria, Physical Review E (2022). DOI: 10.1103/PhysRevE.106.025201

Courtesy of Lawrence Livermore National Laboratory

Citation: Three papers highlighting the record-breaking 1.3 megajoule yield experiment retrieved on August 9, 2022 from https://phys.org/news/2022-08-papers-highlight-results-megajoule-yield.html Results (9 August 2022)

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