(AGENPARL) – mar 15 ottobre 2024 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.
….. LLNL Report, Oct. 11, 2024
Fissile material handler Andy Cose machines a plutonium sample using a lathe
at LLNL’s Superblock Plutonium Facility. (Photo: Garry McLeod/LLNL)
… Pit perfect
As announced by the U.S. Department of Energy’s National Nuclear Security
Administration (NNSA), the First Production Unit (FPU) of a plutonium pit for
the W87-1 Modification Program at Los Alamos National Laboratory (LANL) was
verified as complete on Oct. 1.
This first fully qualified plutonium pit for the W87-1 nuclear warhead was
“diamond stamped” after meeting all requirements, signifying its
readiness for deployment to the U.S. nuclear stockpile at “war reserve”
quality. A plutonium pit is a necessary component in America’s nuclear
warheads which initiates the nuclear reactions when compressed by high
explosives.
Achieving FPU of the W87-1 pit is an important milestone for the United
States’ nuclear weapon stockpile modernization. The W87-1 warhead supports
the Department of Defense’s Sentinel Intercontinental Ballistic Missile
(ICBM), which will be part of the land-based leg of the nation’s nuclear
deterrent and replaces the Minuteman III ICBMs.
Read More
Researchers are understanding how group velocity controls light’s speed in
different conditions. (Credit: Interactive Building Solutions)
… Boxed energy
https://www.ecoticias.com/en/plasma-light-group-velocity/7270/
Almost everyone is raised with the knowledge that the velocity of light in a
vacuum is an absolute value of 299,792 kilometers (186,282 miles) per second.
Even a single photon cannot surpass this speed, but recent studies
demonstrate that at least photons can behave unconventionally under certain
circumstances.
Laser scientists from Lawrence Livermore National Laboratory in California
and the University of Rochester in New York have made this discovery,
enabling new opportunities for advancing laser technology and plasma physics.
The research team looked into controlling the group velocity of light pulses
– in other words, the speed at which light energy moves through a material.
However, group velocity does not have to be a fixed value, as photons travel
at a constant speed to make a classically plausible picture.
Read More https://www.ecoticias.com/en/plasma-light-group-velocity/7270/
LLNL physicist Mordy Rosen enjoys a moment with the blasted target assembly
(left, inside the case) from the groundbreaking December 2022 experiment.
(Photo: Blaise Douros/LLNL)
… The untold story of fusion ignition
https://ww2.aip.org/scilights/the-untold-history-behind-fusion-ignition
On Dec. 5, 2022, researchers at Lawrence Livermore’s  National Ignition
Facility achieved a major milestone in plasma physics: nuclear fusion
ignition. For the first time, a laboratory fusion reaction created more
energy than it consumed.
While the experimental run that reached ignition took just nanoseconds, it
was built on more than 50 years of research. That history was presented by
Mordecai Rosen, who played a key role in all that work leading up to
ignition. He not only detailed the technical work of the experiments, but
also the personal stories of researchers involved, some of whom have been
nearly forgotten to history.
Rosen cited several key lessons that were learned along the way, including
international collaboration, which was increased by efforts to declassify the
research in the 1990s, and external advice, which helped shape an approach
that ultimately enabled ignition. Perhaps foremost in the journey to ignition
was the inherent flexibility of inertial confinement fusion (ICF), which can
vary how the fuel targets are compressed.
Read More
https://ww2.aip.org/scilights/the-untold-history-behind-fusion-ignition
Researchers take soil samples from a rainforest. (Photo: Alexandra Hedgpeth)
… Feeling the burn
https://www.farms.com/news/tropical-forests-face-increased-soil-carbon-loss-due-to-climate-change-215089.aspx
Tropical forests account for more than 50% of the global terrestrial carbon
sink, but climate change threatens to alter the carbon balance of these
ecosystems.
New research by Lawrence Livermore National Laboratory (LLNL) scientists and
colleagues from Colorado State University and the Smithsonian Tropical
Research Institute has found that warming and drying of tropical forest soils
may increase soil carbon vulnerability, by increasing degradation of older
carbon. The research appears
https://www.nature.com/articles/s41467-024-51422-6 in Nature.
“These findings imply that both warming and drying, by accelerating the
loss of older soil carbon or reducing the incorporation of fresh carbon
inputs, will intensify soil carbon losses and negatively impact carbon
storage in tropical forests https://phys.org/tags/tropical+forests/ under
climate change,” said LLNL scientist Karis McFarlane, lead author of the
paper.
Tropical forests exchange more CO2 with the atmosphere than any other
terrestrial biome and store nearly one-third of global soil carbon stocks.
Tropical terrestrial ecosystems also have the shortest mean residence time
for carbon on Earth, as short as 6-15 years, meaning that any change in
carbon inputs or outputs (including CO2 emitted by soil) could have large
and relatively rapid consequences for tropical ecosystem carbon balance and
carbon-climate feedbacks.
Read More
https://www.farms.com/news/tropical-forests-face-increased-soil-carbon-loss-due-to-climate-change-215089.aspx
Dr. Kathryn Mohror, Lawrence Livermore National Laboratory (Credit: LLNL)
… Emerging leader

Dr. Kathryn Mohror Named Emerging Woman Leader In Technical Computing

Dr. Kathryn Mohror, Lawrence Livermore National Laboratory, has been named
the 2024 ACM SIGHPC Emerging Woman Leader In Technical Computing. Dr. Mohror
is a Distinguished Member of the Technical Staff and Deputy Director of the
Laboratory Directed Research and Development Program at Lawrence Livermore
National Laboratory.
Dr. Mohror is a leading researcher who has significantly contributed to a
broad range of HPC I/O topics, programming models, and tools for exascale
computing. Since 2012, she has led the Scalable Checkpoint/Restart Framework
(SCR) effort, an award-winning, production-level checkpoint/restart library
that reduces I/O overhead by orders of magnitude. Within the US Department of
Energy (DOE) Exascale Computing Project (ECP), one of her contributions was
co-leading the development of UnifyFS, a production, user-level file system
designed for node-local storage on supercomputers.
Dr. Mohror is a dedicated and recognized leader within the HPC community. She
has served on over 60 review panels for top-tier HPC conferences, workshops,
and journals. She has had over 25 leadership roles for highly visible HPC
technical activities, including Program Co-Chair for the 2022/23 ECP Annual
Meetings and Technical Program Co-Chair for SC23.
Read More

Dr. Kathryn Mohror Named Emerging Woman Leader In Technical Computing

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Administration.
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