Lab Report

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The Lab Report is a weekly compendium of media reports on science and technology achievements at Lawrence Livermore National Laboratory. Though the Laboratory reviews items for overall accuracy, the reporting organizations are responsible for the content in the links below.

Dec. 2, 2022

climate model

LLNL climate scientists use the Energy Exascale Earth System Model to predict future climate change.

Entering the golden age

In 2021, the United Kingdom experienced an extended period of windlessness; in 2022 it was struck by a record heat wave. At the same time, there were unprecedented flooding in Germany and massive forest fires in France. Are these events part of the violent opening of the anthropogenic warming we’ve been warned about? When and where will they happen next? Climate scientists just don’t know yet.

For nearly six decades, climate models have confirmed what back-of-the-envelope physics already has told us: An increased concentration of greenhouse gases in the atmosphere is warming the planet. Dozens of models, produced by research institutions across the globe, have given visible shape to what lies ahead: time-lapse maps of the world turning from yellow to orange to blood red, ice caps disappearing beneath the ominous contours of temperature gradient lines.

Exascale computers will be able to run models with a much higher resolution — with cells as small as 1 square kilometer — allowing them to directly model more physical processes that happen on finer scales.

The U.S. Department of Energy (DOE) has been developing a program for the past 10 years, preparing to have its Climate and Earth System model ready for this moment. The project, known as E3SM, for Energy Exascale Earth System Model that includes participation from LLNL climate scientists, is specifically geared toward questions of importance to DOE, like how the production of bioenergy will affect land use, and in turn affect the climate system.

NIF hot spots

NIF’s 192 high-energy laser beams converge at the center of the target chamber to implode a tiny hydrogen fuel pellet and spark a thermonuclear fusion reaction.

Ooh, that’s hot

LLNL scientists hoping to harness nuclear fusion—the same energy source that powers the Sun and other stars—have confirmed that magnetic fields can enhance the energy output of their experiments.

Fusion power is generated by the immense energy released as atoms in extreme environments merge together to create new configurations. Scientists have spent roughly a century unraveling the mechanics of nuclear fusion in nature, and trying to artificially replicate this starry mojo in laboratories. 

Now, a team at the National Ignition Facility (NIF) has reported that the magnetic fields can boost the temperature of the fusion “hot spot” in experiments by 40 percent and more than triple its energy output, which is “approaching what is required for fusion ignition.

soil cycle

LLNL researchers used the new high-throughput stable isotope probing (HT-SIP) pipeline and metagenomics to get the first look at the active microbiome surrounding a beneficial plant symbiont, arbuscular mycorrhizal fungi (AMF).

Digging into soil interactions

Linking the identity of wild microbes with their physiological traits and environmental functions is a key aim for environmental microbiologists. Of the techniques that strive for this goal, Stable Isotope Probing — SIP — is considered the most effective for studying active microorganisms in natural settings.

Lawrence Livermore scientists have developed a new technique — high-throughput SIP — that automates several steps in the process of stable isotope probing, allowing investigations of microbial activity of microorganisms under realistic conditions, without the need for lab culturing.

Typically, the SIP method requires substantial hands-on labor and only allows for a small number of samples. But the new LLNL technique requires one-sixth the amount of hands-on labor compared to the manual SIP and allows 16 samples to be processed simultaneously.

“Our semi-automated approach decreases operator time and improves reproducibility by targeting the most labor-intensive steps of SIP,” LLNL scientist Erin Nuccio said. “We have now used this approach to process over a thousand samples, including some from very understudied soil microhabitats.”

NIF yield

Work, conducted at Lawrence Livermore shows that ions behave differently in fusion reactions than previously expected. Image by John Jett and Jake Long/LLNL.

Feel the burn

Last year and after about a decade of trying, physicists working at the mammoth National Ignition Facility (NIF) finally succeeded in generating a self-sustaining fusion reaction. But having since struggled to reproduce the feat, they have been busy trying to work out what makes the results of their experiments so variable. Now, a new finding at NIF may provide a clue – ions in what is known as a burning plasma have an unexpected kinetic energy distribution, which encourages fusion.

The team discovered that ions behave differently in fusion reactions than previously expected, thus providing important insights for the future design of a laser­–fusion energy source.

The work shows that neutron energy measurements on the high-yield burning and igniting inertial confinement fusion experiments (ICF) showed that the average neutron energy produced is higher than expected for a deuterium-tritium (D-T) plasma that is in thermal equilibrium.

Kerlin

From left to right Michelle Greenough, Maryline Kerlin and Bradley Childs in front of the chemical hood used for radioactive material synthesis. The team can prepare air/moisture-sensitive radioactive compounds using Schlenk line techniques, a unique capability in Bldg. 235. Photo by Alexander Wilson-Heid/LLNL

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Uranium goes extreme

Under normal conditions, radioactive materials such as uranium work in a predictable manner.

But take those same materials and put them under extreme conditions with high temperature in a short timescale and a rapid cooling process and their decomposition pathways change dramatically.

Lawrence Livermore scientists built a unique process to synthesize radioactive compounds (uranium-based) that are extremely air- and water-sensitive and require specific techniques. The team was then able to characterize the behavior of these compounds under extreme conditions using a custom-built laser chamber capable of handling radioactive material.

This work explored new reaction pathways for thermal decomposition since the reaction rates are so fast and so far from equilibrium processes. Until now, scientists did not have a good understanding of the chemistry associated with the thermal decomposition of reactive coordination compounds under extreme conditions.

The process could be equated to putting water in a frying pan. If you gradually heat water up, it behaves nicely and boils slowly. However, if you drop water on a hot frying pan (analogous to the laser), the reaction is very different, and water instantly vaporizes.