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Physics
Scientists use simulations to examine the performance of materials in NIF experiments
Scientists have examined the performance of pure boron, boron carbide, high-density carbon and boron nitride ablators — the material that surrounds a fusion fuel and couples with the laser or hohlraum radiation in an experiment — in the polar direct drive exploding pusher (PDXP) platform, which is used at the National Ignition Facility (NIF). The platform uses the polar…
Experiments validate the possibility of helium rain inside Jupiter and Saturn
Nearly 40 years ago, scientists first predicted the existence of helium rain inside planets composed primarily of hydrogen and helium, such as Jupiter and Saturn. However, achieving the experimental conditions necessary to validate this hypothesis hasn’t been possible — until now. In a paper published today by Nature, scientists reveal experimental evidence to support this…
Laser-driven ion acceleration with deep learning
While advances in machine learning over the past decade have made significant impacts in applications such as image classification, natural language processing and pattern recognition, scientific endeavors have only just begun to leverage this technology. This is most notable in processing large quantities of data from experiments. Research conducted at Lawrence Livermore…
The data-driven future of extreme physics
By applying modern machine learning and data science methods to “extreme” plasma physics, researchers can gain insight into our universe and find clues about creating a limitless amount of energy. In a recent perspective published in Nature, Lawrence Livermore National Laboratory (LLNL) scientists and international collaborators outline key challenges and future directions…
Scientists identify key trends in high-energy-density mixing layers
Imagine a bottle of salad dressing containing oil and vinegar. The oil has a lower density than vinegar, so it floats on the vinegar. The oil will not stay trapped under the vinegar if the bottle is flipped upside down. It will bubble up through the vinegar until a stable state is restored. This simple physical process is known as Rayleigh–Taylor instability, and it can be…
It’s only natural: Using environmental microbes to remove uranium from groundwater
Uranium contamination of soils and groundwater in the United States represents a significant health risk and will require multiple remediation approaches. Remediation strategies for uranium-contaminated sites have been the focus of research for decades due to the former production of nuclear materials across the United States. The U.S. Environmental Protection Agency (EPA)…
1D model helps clarify implosion performance at NIF
In inertial confinement fusion (ICF) experiments at the National Ignition Facility (NIF), a spherical shell of deuterium-tritium fuel is imploded in an attempt to reach the conditions needed for fusion, self-heating and eventual ignition. Since theory and simulations indicate that ignition efficacy in one-dimension (1D) improves with increasing imploded fuel convergence…
Sterile neutrinos may be portal to the dark side
“Sterile neutrinos” are theoretically predicted new particles that offer an intriguing possibility in the quest for understanding the dark matter in our universe. Unlike the known “active” neutrinos in the Standard Model (SM) of particle physics, these sterile neutrinos do not interact with normal matter as they move through space, making them very difficult to detect. A…
Scientists reject restrictive heat flux models using directly driven gold spheres
A team of scientists have conducted an analysis of directly driven gold sphere experiments to test heat transport models used in inertial confinement fusion (ICF) and high energy density (HED) modeling. It was found that overly restricting the heat flux caused disagreement with measurement. However, simulations with a reduced nonlocal heat transport model quantitatively…
Researchers construct an EOS delivery paradigm for beryllium
Beryllium is a lightweight, low-density material used in a wide range of applications that require stability at high temperatures and pressures. Because of beryllium’s favorable traits, it has been considered as a potential capsule material for inertial confinement fusion (ICF) applications. Hydrodynamic simulations of ICF are frequently used to model the capsule behavior…
Lab team’s new interferometric instrument improves refractive index measurements at high pressure
In a paper recently published by Scientific Reports, a team of scientists from Lawrence Livermore National Laboratory (LLNL) describes a high-precision interferometer system, newly developed to measure the pressure dependence of the refractive index and its dispersion in diamond anvil cells (DACs). “Accurately measuring the index of a compressed sample in DACs is a…
Researchers isolate geometric effects and resonant scattering in the X-ray spectra of HED plasmas
For the first time, researchers have isolated in a controlled laboratory setting the effects of the plasma geometry in its X-ray emission spectrum – the energy distribution of the radiation the plasmas emit. The work also is the first experimental testbed of the theories describing a phenomenon known in astrophysics as resonant scattering. This phenomenon is found in a…
HPCAT goes remote
Before the COVID-19 pandemic, HPCAT, a Chicago-based research consortium to advance high-pressure science in multidisciplinary fields using synchrotron radiation, hosted as many as 750 experimentalists each year—including numerous Lawrence Livermore National Laboratory (LLNL) teams. The consortium operates Sector 16 at the Advanced Photon Source (APS) at Argonne National…
Scientists put additive manufactured foams to the test
Lawrence Livermore National Laboratory (LLNL) scientists recently published the results of a three-week experimental campaign at the Lab’s Jupiter Laser Facility to test the performance of laser-heated additive manufactured foams. The project helps support two major Laboratory focus areas, including helping to advance additive manufacturing and by enabling improvements in…
Doubling creation of antimatter using same laser energy
Lawrence Livermore National Laboratory (LLNL) scientists have achieved a near 100 percent increase in the amount of antimatter created in the laboratory. Using targets with micro-structures on the laser interface, the team shot a high-intensity laser through them and saw a 100 percent increase in the amount of antimatter (also known as positrons). The research appears in…
Lab launches interdisciplinary Space Science Institute
What are the next world-class, game-changing concepts and technologies that will address the most important questions in astrophysics or planetary science? Lawrence Livermore National Laboratory (LLNL) researchers will soon be better equipped to answer this question with the launch this month of a new Space Science Institute (SSI), intended to boost cross-discipline…
Magnetic fields drive astrophysical jet shapes
Outflows of matter are general features stemming from systems powered by compact objects such as black holes, active galactic nuclei, pulsar wind nebulae, accreting objects such as Young Stellar Objects (YSO) and mature stars such as our sun. But the shape of those outflows, or astrophysical jets, vary depending on the magnetic field around them. In new experiments, a…
LLNL scientists discover a new way that metals freeze at extreme conditions
Since the dawn of civilization, metallurgy has determined the fate of powerful cities, states and empires. Blacksmiths have harnessed the power of heat to melt simple metals that would then be cast into hard, sharp and shiny alloys. Varying process conditions, such as rate of cooling and composition, can lead to new materials with dramatically different mechanical…
Lab team uses giant lasers to compress iron oxide, revealing the secret interior of rocky exoplanets
Advances in astronomical observations have resulted in the discovery of an extraordinary number of extrasolar planets, some of which are believed to have a rocky composition similar to Earth. Learning more about their interior structure could provide important clues about their potential habitability. Led by Lawrence Livermore National Laboratory (LLNL), a team of…
Scientists measure temperature under shock conditions
Temperature is tough to measure, especially in shock compression experiments. A big challenge is having to account for thermal transport — the flow of energy in the form of heat. To better understand this challenge, researchers from Lawrence Livermore National Laboratory (LLNL) have taken important steps to show that thermal conduction is important and measurable at high…
