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.

Nov. 11, 2022

fusion cylinder

In this experiment at the National Ignition Facility, 192 laser beams (violet) heat a metal cylinder whose x-ray glow heats the spherical fuel capsule (center), driving a fusion reaction. A wire coil (copper color) generates a strong magnetic field that can triple the fusion reaction’s energy output.

It’s magnetizing

A magnetic field can significantly boost the performance of a large-scale fusion experiment that may lead to a future source of clean power.

Nuclear fusion could provide a clean power source, but one of the technological challenges is maintaining the fuel at a high enough temperature for a long enough time. In a technique called inertial confinement fusion (ICF) — where lasers initiate the nuclear reaction — a magnetic field has been shown to improve heating.

Researchers at Lawrence Livermore have used computer simulations to study the potential benefits of magnetization for performance at NIF, the world’s largest ICF experiment and the one that has come closest to the goal of producing more energy than it consumes. Earlier OMEGA results proved the basic concept, but they could not be applied directly to NIF, since NIF uses a design called indirect drive, in which the laser pulses heat a hollow gold cylinder so much that it glows in X-rays. This radiation in turn illuminates and heats the fuel capsule, which is located inside the cylinder and causes the capsule to implode.

Exposing a gold cylinder to a strong magnetic field would generate electric currents in its walls that would destroy it. To get around this problem, LLNL scientist John Moody and his colleagues experimented with alloys to create a metal cylinder with low electrical conductivity. They found that an alloy of gold and tantalum could tolerate the high magnetic field.

nExo

Human silhouettes illustrate the scale of the nEXO detector, which will be built in a cavern two kilometers underground. The xenon, located in the center, is protected from radioactive background by a cylindrical copper vessel, a sphere of special fluid and a water tank.

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The nEXO big thing

Lawrence Livermore (LLNL) has received $2.35 million from the Inflation Reduction Act, which aims to support domestic energy production and promote clean energy and to provide the Department of Energy (DOE) national laboratories with resources to keep the U.S. at the forefront of scientific discovery.

The funding has been allocated for the Lab-led nEXO project, which was created to understand neutrinos — tiny, nearly massless particles with no charge. The goal of the nEXO experiment is to search for a rare type of nuclear decay called neutrinoless double beta decay (NDBD). Double beta decay is a process where a nucleus decays into another one and emits two electrons and two antineutrinos. A special version of double beta decay — the “neutrinoless” version — emits only two electrons and no antineutrinos. If this is found, it would be a major discovery observing the generation of matter without antimatter and would provide insight into the formation of the universe.

“The nEXO project will provide information about the nature of the neutrino and ultimately insight to why we exist,” said LLNL physicist and project director Mike Heffner. “Furthering the understanding of neutrinos and their properties provides tremendous insight into the formation of the universe. nEXO is designed to address this top DOE nuclear physics mission need and will provide important U.S. scientific leadership in the world.”

nanotube

Vertically aligned carbon nanotubes growing from catalytic nanoparticles (gold color) on a silicon wafer on top of a heating stage (red glow). Diffusion of acetylene (black molecules) through the gas phase to the catalytic sites determines the growth rate in a cold-wall showerhead reactor. Image by Adam Samuel Connell/LLNL.

The nanotubes are but wafer-thin

Scientists at Lawrence Livermore National Laboratory (LLNL) are scaling up the production of vertically aligned single-walled carbon nanotubes. This incredible material could revolutionize diverse commercial products ranging from rechargeable batteries, sporting goods, and automotive parts to boat hulls and water filters.

Most carbon nanotube (CNT) production today is unorganized CNT architectures that is used in bulk composite materials and thin films. However, for many uses, organized CNT architectures, like vertically aligned forests, provide critical advantages for exploiting the properties of individual CNTs in macroscopic systems.

“Robust synthesis of vertically-aligned carbon nanotubes at large scale is required to accelerate deployment of numerous cutting-edge devices to emerging commercial applications,” said LLNL scientist and lead author Francesco Fornasiero. “To address this need, we demonstrated that the structural characteristics of single-walled CNTs produced at wafer scale in a growth regime dominated by bulk diffusion of the gaseous carbon precursor are remarkably invariant over a broad range of process conditions.”

viruses

In grassland soils, the types of viruses are dramatically different over short distances in space and time. The makeup of viral communities also was very sensitive to changes in soil moisture caused by an experimental drought. These effects may have downstream implications for the amount and pathways of soil-carbon cycling. Image by Christian Santos Medellín/UC Davis.

Come rain or shine

Soils contain diverse communities of microorganisms, including bacteria, fungi, protists and viruses. Interactions between these tiny organisms shape the ability of soils to store carbon underground.

However, not much is known about the spatial patterns and dynamics of viral communities in soil.

New research by Lawrence Livermore National Laboratory (LLNL) scientists and collaborators show that grassland viral communities are highly spatially stratified across just a single field, suggesting strong dispersal limitations at the local scale.

"Knowing the composition and turnover of viral communities across space and time is necessary to begin unraveling what constrains host-virus interactions in soil," said LLNL scientist Jennifer Pett-Ridge. "We found that the soil ‘virosphere’' is highly diverse, dynamic, active and spatially structured; it also appears to be capable of rapid responses to changing environmental conditions, particularly the amount of rainfall."

winners

The SUNDIALS core development team at Lawrence Livermore National Laboratory has been named the winner of the prestigious 2023 SIAM/ACM Prize in Computational Science and Engineering. Team members (from left, clockwise): LLNL computational mathematician/Distinguished Member of the Technical Staff Carol Woodward, computational scientists Cody Balos and David Gardner, senior scientist Peter Brown, LLNL guest scholar and retiree Alan Hindmarsh, former LLNL postdoc Daniel Reynolds and former LLNL scientist Radu Serban.

Here comes the sun

The Society for Industrial and Applied Mathematics (SIAM) and Association for Computing Machinery (ACM) announced that they have awarded the 2023 SIAM/ACM Prize in Computational Science and Engineering to the team behind the Lawrence Livermore National Laboratory (LLNL)-developed SUNDIALS software suite.

The prestigious award is handed out every two years and recognizes outstanding contributions to the development and use of mathematical and computational tools and methods for the solution of science and engineering problems. It is one of SIAM’s most significant awards and will be presented to the team at the 2023 SIAM Conference on Computational Science and Engineering in Amsterdam next February. It includes a monetary prize and a certificate.

The SUNDIALS core development team is led by computational mathematician Carol Woodward, a Distinguished Member of the Technical Staff at LLNL, and includes LLNL computational scientists Cody Balos and David Gardner, senior scientist Peter Brown,  LLNL guest scholar and retiree Alan Hindmarsh, former LLNL postdoc Daniel Reynolds and former LLNL scientist Radu Serban.