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  • richardmitnick 9:59 am on September 25, 2021 Permalink | Reply
    Tags: "Lawrence Livermore researchers focus on fast flows in thermonuclear fusion", , , NIF-National Ignition Facility   

    From DOE’s Lawrence Livermore National Laboratory (US) : “Lawrence Livermore researchers focus on fast flows in thermonuclear fusion” 

    From DOE’s Lawrence Livermore National Laboratory (US)

    9.24.21

    Michael Padilla
    padilla37@llnl.gov
    925-341-8692

    1
    Multi-part figure showing measured and simulated flows within an imploding ICF hot spot. (a) Time-resolved x-ray emission is used to track the bright “tracer” particle during an implosion. (b) Horizontal and (c) vertical flow velocity for three asymmetry drives: Upward (▲) and downward (▼) driven implosions show strong large vertical flows. (d) Streamline data of internal flows from downward (▼) drive, overlaid on flow field from 2D HYDRA simulation at tbang + 65 ps.

    Imagine having a balloon between both hands and trying to squeeze it with the same force on all sides so that it uniformly shrinks down. However, if you push on one side harder than the other the balloon won’t compress uniformly and will, in fact, move away from the hand that is pushing harder.

    The same thing happens when the drive pushing on an inertial confinement fusion (ICF) capsule is imbalanced — if it pushes harder on the top than on the bottom the capsule will move downward. This motion detracts from the energy heating the capsule and generating fusion. A short leap is to imagine two pistons compressing this gas instead of hands.

    That is how Dave Schlossberg, Lawrence Livermore National Laboratory (LLNL) staff scientist, explains the effect of laser drive asymmetry. Schlossberg is the lead author in a recently published paper in in Physical Review LettersImagine having a balloon between both hands and trying to squeeze it with the same force on all sides so that it uniformly shrinks down. However, if you push on one side harder than the other the balloon won’t compress uniformly and will, in fact, move away from the hand that is pushing harder.

    The same thing happens when the drive pushing on an inertial confinement fusion (ICF) capsule is imbalanced — if it pushes harder on the top than on the bottom the capsule will move downward. This motion detracts from the energy heating the capsule and generating fusion. A short leap is to imagine two pistons compressing this gas instead of hands [Physics of Plasmas].

    That is how Dave Schlossberg, Lawrence Livermore National Laboratory (LLNL) staff scientist, explains the effect of laser drive asymmetry. Schlossberg is the lead author in a recently published paper in Physical Review Letters.

    The team conducted experiments at the National Ignition Facility [below] to investigate a “low-mode” laser asymmetry that was significantly degrading performance. The results from the work led to a detailed understanding of this degradation from the very small-scale up to the largest scale.

    “With this knowledge it’s possible to reduce asymmetries and increase performance — which was recently accomplished,” he said, adding that this is one in a series of experiments over the last several years remediating degradations from radiative losses [Physical Review Letters], engineering features [Physical Review Letters] and ablator asymmetries[Physical Review Letters].

    Characterizing measurements

    There are four key findings from this work that include: measured signatures of asymmetric laser drive; agreement between simulation and experiment; quantification of Doppler-broadening in apparent ion temperature with increased bulk plasma motion; and relating observed, driven hot spot flows to macroscopic input parameters.

    “In experimental science we only know what we can measure — so first we needed to characterize the measurements that show these implosions suffered from laser drive asymmetry,” he explained. “The natural next step was to compare these measurements with models and see if they agreed, and they did.”

    One product of deuterium-tritium fusion is a neutron traveling 51,234 km/s in the center-of-mass frame — that’s ~17 percent the speed of light. If the plasma producing these neutrons also is moving with some velocity, then that velocity is added to the neutron. The team showed that small variances in this neutron velocity directly related to broadening of the measured, time-of-flight neutron spectrum.

    “Think of it as measuring the arrival time of a bullet fired from a gun, where a bullet represents a neutron,” he proposed. “If you’re a precision sharpshooter standing absolutely still every time you fire a bullet, it will arrive at the target at exactly the same time. But, now say you’re running and firing, then some bullets arrive sooner and some later depending how fast you’re moving each time you fire the gun.”

    Schlossberg said the same thing is true in the imploding, fusing plasma that’s producing neutrons while it’s moving. The neutron time-of-flight diagnostic precisely measures neutron arrival times and relates them to the plasma’s internal energy. If there’s additional spread in the arrival times because the plasma is moving, that’s an important consideration when inferring the plasma thermal temperature. This work characterized how the apparent ion temperature increases due to variance in the deuterium-tritium velocities.

    Mapping flows in fusing plasma

    The final finding of this work is direct measurement of the flowing deuterium-tritium ions within the fusing hot spot.

    “Here we got a bit lucky, since some of the tungsten used to dope the capsule was injected into the hot plasma and lit up brightly in the X-ray range,” Schlossberg acknowledged.

    It served as a tracer particle for these internal flows. By tracking the motion of this tracer particle over time, the team mapped out a flow line while the plasma was fusing. This is important since these flows are the cause of the increased apparent temperature, and it showed consistency between both measurements.

    The team used this measurement to connect flows within the microscopic hot spot to asymmetries in the macroscopic laser-drive. When they balanced the laser drive these flows disappeared (see Bal. trace ● in figure). These findings combine to provide a comprehensive understanding of the effects of laser drive asymmetry on implosion performance, and shows agreement across experiment, simulation and theory. This provides confidence for future work to identify and reduce these asymmetries in laser drive, leading to overall improved performance.

    “When we saw preliminary time-resolved, X-ray imaging soon after the first shot we were immediately intrigued — something spectacular was showing up, which ended up being the time-resolved motion of the tracer particle traveling through the hot spot,” Schlossberg said. “This material was traveling ~0.1 percent the speed of light through material ~10 times denser than solid material.”

    “It’s truly a team effort, and I’m thrilled and humbled to be part of such a great group of people,” Schlossberg expressed, adding that work was done by a team of NIF scientists and engineers spanning across groups that handle data analysis, target fabrication, operations and diagnostics.

    In addition to Schlossberg, co-authors include: Gary Grim, Dan Casey, Alastair Moore, Ryan Nora, Ben Bachmann, Laura Robin Benedetti, Richard Bionta, Mark Eckart, John Field, David Fittinghoff, Edward Hartouni, Robert Hatarik, Warren Hsing, Leonard Charles Jarrott, Shahab Khan, Otto Landen, Brian MacGowan, Andrew Mackinnon, David Munro, Sabrina Nagel, Art Pak, Prav Patel, Brian Spears, and Chris Young from LLNL; Maria Gatu-Johnson from The Massachusetts Institute of Technology (US); Verena Geppert-Kleinrath and Kevin Meaney from DOE’s Los Alamos National Laboratory (US); and Joseph Kilkenny from General Atomics (US).

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration

    DOE’s Lawrence Livermore National Laboratory (LLNL) (US) is an American federal research facility in Livermore, California, United States, founded by the University of California-Berkeley (US) in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System (US). In 2012, the laboratory had the synthetic chemical element livermorium named after it.

    LLNL is self-described as “a premier research and development institution for science and technology applied to national security.” Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.

    The Laboratory is located on a one-square-mile (2.6 km^2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.

    LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence, director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.

    The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined thermonuclear reactions (i.e. fusion). About half an hour southeast of Berkeley, the Livermore site provided much greater security for classified projects than an urban university campus.

    Lawrence tapped 32-year-old Herbert York, a former graduate student of his, to run Livermore. Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the DOE’s Los Alamos National Laboratory(US) and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence “big science” approach, tackling challenging projects with physicists, chemists, engineers, and computational scientists working together in multidisciplinary teams. Lawrence died in August 1958 and shortly after, the university’s board of regents named both laboratories for him, as the Lawrence Radiation Laboratory.

    Historically, the DOE’s Lawrence Berkeley National Laboratory (US) and Livermore laboratories have had very close relationships on research projects, business operations, and staff. The Livermore Lab was established initially as a branch of the Berkeley laboratory. The Livermore lab was not officially severed administratively from the Berkeley lab until 1971. To this day, in official planning documents and records, Lawrence Berkeley National Laboratory is designated as Site 100, Lawrence Livermore National Lab as Site 200, and LLNL’s remote test location as Site 300.

    The laboratory was renamed Lawrence Livermore Laboratory (LLL) in 1971. On October 1, 2007 LLNS assumed management of LLNL from the University of California, which had exclusively managed and operated the Laboratory since its inception 55 years before. The laboratory was honored in 2012 by having the synthetic chemical element livermorium named after it. The LLNS takeover of the laboratory has been controversial. In May 2013, an Alameda County jury awarded over $2.7 million to five former laboratory employees who were among 430 employees LLNS laid off during 2008.The jury found that LLNS breached a contractual obligation to terminate the employees only for “reasonable cause.” The five plaintiffs also have pending age discrimination claims against LLNS, which will be heard by a different jury in a separate trial.[6] There are 125 co-plaintiffs awaiting trial on similar claims against LLNS. The May 2008 layoff was the first layoff at the laboratory in nearly 40 years.

    On March 14, 2011, the City of Livermore officially expanded the city’s boundaries to annex LLNL and move it within the city limits. The unanimous vote by the Livermore city council expanded Livermore’s southeastern boundaries to cover 15 land parcels covering 1,057 acres (4.28 km^2) that comprise the LLNL site. The site was formerly an unincorporated area of Alameda County. The LLNL campus continues to be owned by the federal government.


    NNSA

     
  • richardmitnick 2:11 pm on January 7, 2021 Permalink | Reply
    Tags: "Researchers develop broadband X-ray source needed to perform new measurements at NIF", , It is the goal of the EXAFS platform to test the thermal models underpinning the equation of state models used in hydrodynamics codes as well as complement the other materials platforms., Lawrence Livermore National Laboratory (LLNL) researchers have developed an X-ray source that can diagnose temperature in experiments that probe conditions like those at the very center of planets., NIF-National Ignition Facility, , The new source will be used to perform extended X-ray absorption fine structure (EXAFS) experiments at the National Ignition Facility (NIF)., The primary motivation of the EXAFS experiments is to determine the temperature of samples at Mbar pressures—conditions like those at the very center of planets., While there are many uses for X-ray sources the work was primarily focused on making it possible to measure EXAFS of highly compressed materials in the solid state.   

    From DOE’s Lawrence Livermore National Laboratory via phys.org: “Researchers develop broadband X-ray source needed to perform new measurements at NIF” 

    From DOE’s Lawrence Livermore National Laboratory

    via


    From phys.org

    January 7, 2021
    Michael Padilla, Lawrence Livermore National Laboratory

    1
    This image shows the full EXAFS sample, backlighter and laser configuration at the National Ignition Facility. Credit: Lawrence Livermore National Laboratory.

    Lawrence Livermore National Laboratory (LLNL) researchers have developed an X-ray source that can diagnose temperature in experiments that probe conditions like those at the very center of planets.

    The new source will be used to perform extended X-ray absorption fine structure (EXAFS) experiments at the National Ignition Facility (NIF) [see below].

    The work was published in Applied Physics Letters and was featured as an Editor’s Pick.

    “Over a series of X-ray source development experiments at NIF, we were able to determine that titanium (Ti) foils produce 30 times more continuum X-rays than implosion capsule backlighters in the X-ray spectral range of interest and between two to four times more than gold (Au) foils under identical laser conditions,” said Andy Krygier, LLNL physicist and lead author.

    Understanding extended X-ray absorption fine structure

    “While there are many uses for X-ray sources, the work was primarily focused on making it possible to measure EXAFS of highly compressed materials in the solid state. This is a very difficult regime to operate in and ultimately required a lot of effort and resources to accomplish,” Krygier said.

    The primary motivation of the EXAFS experiments is to determine the temperature of samples at Mbar pressures—conditions like those at the very center of planets (1 Mbar = 1 million times atmospheric pressure). “With this work, we now have the ability to perform EXAFS measurements at NIF over a wide range of materials and conditions that were not previously possible at any facility in the world.”

    At these conditions, where solids can be compressed by a factor of two or more, the materials can have wildly different properties than at everyday ambient conditions. The X-ray source developed in this work will enable measurements of various higher-Z materials that are of importance for the Lab’s mission. This platform also will open up opportunities for scientific discovery in material properties under extreme conditions.

    Measuring EXAFS requires detecting signals that are a few percent of the overall signal and is the underlying reason that the team has put so much effort into developing an intense, spectrally smooth backlighter.

    Yuan Ping, LLNL physicist and the campaign lead of the work, said the findings conclude a success in the development of backlighter for the EXAFS project. “EXAFS measurements using this backlighter have already started at NIF and the approach is expected to enable future measurements that are a critical part of LLNL’s support of NNSA’s Stockpile Stewardship Program,” she said.

    The preferred arrangement of atoms or crystal structure changes with temperature and pressure in many materials and is currently investigated by the TARDIS (target diffraction in situ) platform at NIF. The structure also is one of many things impacting the relationship between pressure and density, which is under investigation by the ramp compression platform at NIF, as well as the strength, which is under investigation by the RT platform at NIF.

    “All of these important platforms lack temperature measurements,” Krygier said. “It is the goal of the EXAFS platform to test the thermal models underpinning the equation of state models used in hydrodynamics codes as well as complement the other materials platforms.”

    There has been a lot of effort developing X-ray sources using heated foils by other teams, but these efforts have often focused on different X-ray energies or optimizing line emission (a narrow-in-energy X-ray emission resulting from an atomic transition), Krygier said.

    “EXAFS experiments explicitly require a different type of X-ray source than many others at NIF,” he said. “Because the EXAFS signal is encoded over a relatively wide, but specific, range of X-ray energies, we needed to optimize the broadband continuum emission in the multi-keV energy range, instead of the line emission, which is far too narrow in energy for EXAFS.”

    The team has determined that it is possible, by using the very high power density of the NIF lasers, to ionize titanium into its inner shell. “This high degree of ionization enables a continuum X-ray emission process called free-bound to become important and actually dominate the overall continuum X-ray emission,” he said.

    Krygier said this process leads to a stronger continuum emission in the multi-keV regime from titanium than from silver or gold. “The observation that heating a titanium foil produces stronger continuum emission than with silver or gold was unexpected initially, but after careful data analysis, we determined that free-bound transitions were playing an important role. In the end, the data and model agree nicely.” he said.

    Elijah Kemp, LLNL physicist, aided in the interpretation of the data with the rad-hydro (HYDRA) and atomic-kinetics (SCRAM) modeling that helped confirm the data interpretation. He said scientists have a tendency to carry around a standard toolbox of generalized scaling laws for various physical phenomena that lead to the assumption that an gold backlighter would outperform silver and titanium. Continuum X-ray emission is generally known to increase with the atomic number, however, heating the sample to the regime where free-bound transitions was important enabled titaniumi, whose atomic number is 22, to outshine silver and gold, whose atomic numbers are 47 and 79, respectively.

    “While these ubiquitous scalings can help to quickly guide one’s intuition, they also can lead to seemingly paradoxical results,” he said. “One of the most important messages from this work is to not naively rely on overgeneralized rules-of-thumb that are so often employed to prematurely narrow down parameter optimization studies.”

    Team effort

    This effort required the team to look beyond typical X-ray emission processes to understand the data from experiments. They relied on experts across a wide range of disciplines including materials science, plasma physics, X-ray spectroscopy and hydrodynamic simulation during planning and analysis.

    The team was initially focused on a different approach, using imploding capsules, but eventually determined that it was not going to produce enough X-rays to make EXAFS measurements.

    “It’s one of the few times where science actually works the way it’s portrayed in movies with everyone on the team in a room (back when we could meet in rooms) proposing ideas on a whiteboard,” Krygier said. “Results like this are a real testament to the world-class research environment that exists at LLNL.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition


    Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration
    DOE’s Lawrence Livermore National Laboratory (LLNL) is an American federal research facility in Livermore, California, United States, founded by the University of California, Berkeley in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System. In 2012, the laboratory had the synthetic chemical element livermorium named after it.
    LLNL is self-described as “a premier research and development institution for science and technology applied to national security.” Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.

    The Laboratory is located on a one-square-mile (2.6 km2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.

    LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence,[2] director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.

    The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined thermonuclear reactions (i.e. fusion). About half an hour southeast of Berkeley, the Livermore site provided much greater security for classified projects than an urban university campus.

    Lawrence tapped 32-year-old Herbert York, a former graduate student of his, to run Livermore. Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the Los Alamos and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence “big science” approach, tackling challenging projects with physicists, chemists, engineers, and computational scientists working together in multidisciplinary teams. Lawrence died in August 1958 and shortly after, the university’s board of regents named both laboratories for him, as the Lawrence Radiation Laboratory.

    Historically, the Berkeley and Livermore laboratories have had very close relationships on research projects, business operations, and staff. The Livermore Lab was established initially as a branch of the Berkeley laboratory. The Livermore lab was not officially severed administratively from the Berkeley lab until 1971. To this day, in official planning documents and records, Lawrence Berkeley National Laboratory is designated as Site 100, Lawrence Livermore National Lab as Site 200, and LLNL’s remote test location as Site 300.[3]

    The laboratory was renamed Lawrence Livermore Laboratory (LLL) in 1971. On October 1, 2007 LLNS assumed management of LLNL from the University of California, which had exclusively managed and operated the Laboratory since its inception 55 years before. The laboratory was honored in 2012 by having the synthetic chemical element livermorium named after it. The LLNS takeover of the laboratory has been controversial. In May 2013, an Alameda County jury awarded over $2.7 million to five former laboratory employees who were among 430 employees LLNS laid off during 2008.[4] The jury found that LLNS breached a contractual obligation to terminate the employees only for “reasonable cause.”[5] The five plaintiffs also have pending age discrimination claims against LLNS, which will be heard by a different jury in a separate trial.[6] There are 125 co-plaintiffs awaiting trial on similar claims against LLNS.[7] The May 2008 layoff was the first layoff at the laboratory in nearly 40 years.[6]

    On March 14, 2011, the City of Livermore officially expanded the city’s boundaries to annex LLNL and move it within the city limits. The unanimous vote by the Livermore city council expanded Livermore’s southeastern boundaries to cover 15 land parcels covering 1,057 acres (4.28 km2) that comprise the LLNL site. The site was formerly an unincorporated area of Alameda County. The LLNL campus continues to be owned by the federal government.

    LLNL/NIF


    DOE Seal
    NNSA

     
  • richardmitnick 11:32 am on November 15, 2020 Permalink | Reply
    Tags: , , , , , NIF-National Ignition Facility, , , , , U Rochester OMEGA Laser Facility   

    From From DOE’s Lawrence Livermore National Laboratory via Science News: “Giant lasers help re-create supernovas’ explosive, mysterious physics” 

    From DOE’s Lawrence Livermore National Laboratory

    via

    Science News

    November 12, 2020
    Emily Conover

    1
    Researchers are re-creating the physics of cosmic explosions using the world’s most energetic lasers, such as the one at OMEGA (shown) at the University of Rochester in New York. Credit: Eugene Kowaluk/Univ. of Rochester Laboratory for Laser Energetics.

    Pocket-sized blasts in the lab reveal details of massive stellar explosions.

    When one of Hye-Sook Park’s experiments goes well, everyone nearby knows. “We can hear Hye-Sook screaming,” she’s heard colleagues say.

    Science paper:
    Electron acceleration in laboratory-produced turbulent collisionless shocks
    Nature Physics

    It’s no surprise that she can’t contain her excitement. She’s getting a closeup look at the physics of exploding stars, or supernovas, a phenomenon so immense that its power is difficult to put into words.

    Rather than studying these explosions from a distance through telescopes, Park, a physicist at Lawrence Livermore National Laboratory in California, creates something akin to these paroxysmal blasts using the world’s highest-energy lasers.

    About 10 years ago, Park and colleagues embarked on a quest to understand a fascinating and poorly understood feature of supernovas: Shock waves that form in the wake of the explosions can boost particles, such as protons and electrons, to extreme energies.

    “Supernova shocks are considered to be some of the most powerful particle accelerators in the universe,” says plasma physicist Frederico Fiuza of SLAC National Accelerator Laboratory in Menlo Park, Calif., one of Park’s collaborators.

    Some of those particles eventually slam into Earth, after a fast-paced marathon across cosmic distances. Scientists have long puzzled over how such waves give energetic particles their massive speed boosts. Now, Park and colleagues have finally created a supernova-style shock wave in the lab and watched it send particles hurtling, revealing possible new hints about how that happens in the cosmos.

    Bringing supernova physics down to Earth could help resolve other mysteries of the universe, such as the origins of cosmic magnetic fields. And there’s a more existential reason physicists are fascinated by supernovas. These blasts provide some of the basic building blocks necessary for our existence. “The iron in our blood comes from supernovae,” says plasma physicist Carolyn Kuranz of the University of Michigan in Ann Arbor, who also studies supernovas in the laboratory. “We’re literally created from stars.”

    Lucky star

    As a graduate student in the 1980s, Park worked on an experiment 600 meters underground in a working salt mine beneath Lake Erie in Ohio. Called IMB for Irvine-Michigan-Brookhaven, the experiment wasn’t designed to study supernovas. But the researchers had a stroke of luck. A star exploded in a satellite galaxy of the Milky Way, and IMB captured particles catapulted from that eruption. Those messengers from the cosmic explosion, lightweight subatomic particles called neutrinos, revealed a wealth of new information about supernovas.

    But supernovas in our cosmic vicinity are rare. So decades later, Park isn’t waiting around for a second lucky event.

    2
    Physicist Hye-Sook Park, shown as a graduate student in the 1980s (left) and in a recent photo (right), uses powerful lasers to study astrophysics. Credit:from left John Van der Velde; Lanie L. Rivera/Lawrence Livermore National Laboratory.

    Instead, her team and others are using extremely powerful lasers to re-create the physics seen in the aftermath of supernova blasts. The lasers vaporize a small target, which can be made of various materials, such as plastic. The blow produces an explosion of fast-moving plasma, a mixture of charged particles, that mimics the behavior of plasma erupting from supernovas.

    The stellar explosions are triggered when a massive star exhausts its fuel and its core collapses and rebounds. Outer layers of the star blast outward in an explosion that can unleash more energy than will be released by the sun over its entire 10-billion-year lifetime. The outflow has an unfathomable 100 quintillion yottajoules of kinetic energy (SN: 2/8/17, p. 24).

    Supernovas can also occur when a dead star called a white dwarf is reignited, for example after slurping up gas from a companion star, causing a burst of nuclear reactions that spiral out of control (SN: 4/30/16, p. 20).

    3
    Supernova remnants like W49B (shown in X-ray, radio and infrared light) accelerate electrons and protons to high energies in shock waves. Credit: NASA, CXC, MIT L. Lopez et al (X-ray), Palomar (Infrared), VLA/NRAO/NSF (Radio)

    NASA Chandra X-ray Space Telescope

    Caltech Palomar 200 inch Hale Telescope, Altitude 1,713 m (5,620 ft), located in San Diego County, California, U.S.A.

    NRAO Karl G Jansky Very Large Array, located in central New Mexico on the Plains of San Agustin, between the towns of Magdalena and Datil, ~50 miles (80 km) west of Socorro. The VLA comprises twenty-eight 25-meter radio telescopes.

    In both cases, things really get cooking when the explosion sends a blast of plasma careening out of the star and into its environs, the interstellar medium — essentially, another ocean of plasma particles. Over time, a turbulent, expanding structure called a supernova remnant forms, begetting a beautiful light show, tens of light-years across, that can persist in the sky for many thousands of years after the initial explosion. It’s that roiling remnant that Park and colleagues are exploring.

    Studying supernova physics in the lab isn’t quite the same thing as the real deal, for obvious reasons. “We cannot really create a supernova in the laboratory, otherwise we would be all exploded,” Park says.

    In lieu of self-annihilation, Park and others focus on versions of supernovas that are scaled down, both in size and in time. And rather than reproducing the entirety of a supernova all at once, physicists try in each experiment to isolate interesting components of the physics taking place. Out of the immense complexity of a supernova, “we are studying just a tiny bit of that, really,” Park says.

    For explosions in space, scientists are at the mercy of nature. But in the laboratory, “you can change parameters and see how shocks react,” says astrophysicist Anatoly Spitkovsky of Princeton University, who collaborates with Park.

    The laboratory explosions happen in an instant and are tiny, just centimeters across. For example, in Kuranz’s experiments, the equivalent of 15 minutes in the life of a real supernova can take just 10 billionths of a second. And a section of a stellar explosion larger than the diameter of Earth can be shrunk down to 100 micrometers. “The processes that occur in both of those are very similar,” Kuranz says. “It blows my mind.”


    How to make a fake supernova | Science News
    Powerful, mysterious stellar explosions are difficult to understand from afar, so researchers have figured out how to re-create supernovas’ extreme physics in the lab and study how outbursts seed the cosmos with elements and energetic particles.

    Laser focus

    To replicate the physics of a supernova, laboratory explosions must create an extreme environment. For that, you need a really big laser, which can be found in only a few places in the world, such as NIF, the National Ignition Facility at Lawrence Livermore, and the OMEGA Laser Facility at the University of Rochester in New York.

    At both places, one laser is split into many beams. The biggest laser in the world, at NIF, has 192 beams. Each of those beams is amplified to increase its energy exponentially. Then, some or all of those beams are trained on a small, carefully designed target. NIF’s laser can deliver more than 500 trillion watts of power for a brief instant, momentarily outstripping the total power usage in the United States by a factor of a thousand.

    A single experiment at NIF or OMEGA, called a shot, is one blast from the laser. And each shot is a big production. Opportunities to use such advanced facilities are scarce, and researchers want to have all the details ironed out to be confident the experiment will be a success.

    When a shot is about to happen, there’s a space-launch vibe. Operators monitor the facility from a control room filled with screens. When the time of the laser blast nears, a voice begins counting down: “Ten, nine, eight …”

    “When they count down for your shot, your heart is pounding,” says plasma physicist Jena Meinecke of the University of Oxford, who has worked on experiments at NIF and other laser facilities.

    At the moment of the shot, “you kind of want the Earth to shake,” Kuranz says. But instead, you might just hear a snap — the sound of the discharge from capacitors that store up huge amounts of energy for each shot.

    Then comes a mad dash to review the results and determine if the experiment has been successful. “It’s a lot of adrenaline,” Kuranz says.

    NIL

    National Ignition Facility at DOE’s Lawrence Livermore National Laboratory.

    3
    At the National Ignition Facility’s target chamber (shown during maintenance), 192 laser beams converge. The blasts produce plumes of plasma that can mimic some aspects of supernova remnants.Credit: Lawrence Livermore National Laboratory.

    Lasers aren’t the only way to investigate supernova physics in the lab. Some researchers use intense bursts of electricity, called pulsed power. Others use small amounts of explosives to set off blasts. The various techniques can be used to understand different stages in supernovas’ lives.

    A real shocker

    Park brims with cosmic levels of enthusiasm, ready to erupt in response to a new nugget of data or a new success in her experiments. Re-creating some of the physics of a supernova in the lab really is as remarkable as it sounds, she says. “Other­wise I wouldn’t be working on it.” Along with Spitkovsky and Fiuza, Park is among more than a dozen scientists involved in the Astrophysical Collisionless Shock Experiments with Lasers collaboration, or ACSEL, the quest Park embarked upon a decade ago. Their focus is shock waves.

    The result of a violent input of energy, shock waves are marked by an abrupt increase in temperature, density and pressure. On Earth, shock waves cause the sonic boom of a supersonic jet, the clap of thunder in a storm and the damaging pressure wave that can shatter windows in the aftermath of a massive explosion. These shock waves form as air molecules slam into each other, piling up molecules into a high-density, high-pressure and high-temperature wave.

    In cosmic environments, shock waves occur not in air, but in plasma, a mixture of protons, electrons and ions, electrically charged atoms. There, particles may be diffuse enough that they don’t directly collide as they do in air. In such a plasma, the pileup of particles happens indirectly, the result of electromagnetic forces pushing and pulling the particles. “If a particle changes trajectory, it’s because it feels a magnetic field or an electric field,” says Gianluca Gregori, a physicist at the University of Oxford who is part of ACSEL.

    But exactly how those fields form and grow, and how such a shock wave results, has been hard to decipher. Researchers have no way to see the process in real supernovas; the details are too small to observe with telescopes.

    These shock waves, which are known as collisionless shock waves, fascinate physicists. “Particles in these shocks can reach amazing energies,” Spitkovsky says. In supernova remnants, particles can gain up to 1,000 trillion electron volts, vastly outstripping the several trillion electron volts reached in the biggest human-made particle accelerator, the Large Hadron Collider near Geneva. But how particles might surf supernova shock waves to attain their astounding energies has remained mysterious.

    Magnetic field origins

    To understand how supernova shock waves boost particles, you have to understand how shock waves form in supernova remnants. To get there, you have to understand how strong magnetic fields arise. Without them, the shock wave can’t form.

    Electric and magnetic fields are closely intertwined. When electrically charged particles move, they form tiny electric currents, which generate small magnetic fields. And magnetic fields themselves send charged particles corkscrewing, curving their trajectories. Moving magnetic fields also create electric fields.

    The result is a complex feedback process of jostling particles and fields, eventually producing a shock wave. “This is why it’s so fascinating. It’s a self-modulating, self-controlling, self-reproducing structure,” Spitkovsky says. “It’s like it’s almost alive.”

    All this complexity can develop only after a magnetic field forms. But the haphazard motions of individual particles generate only small, transient magnetic fields. To create a significant field, some process within a supernova remnant must reinforce and amplify the magnetic fields. A theoretical process called the Weibel instability, first thought up in 1959, has long been expected to do just that.

    In a supernova, the plasma streaming outward in the explosion meets the plasma of the interstellar medium. According to the theory behind the Weibel instability, the two sets of plasma break into filaments as they stream by one another, like two hands with fingers interlaced. Those filaments act like current-­carrying wires. And where there’s current, there’s a magnetic field. The filaments’ magnetic fields strengthen the currents, further enhancing the magnetic fields. Scientists suspected that the electromagnetic fields could then become strong enough to reroute and slow down particles, causing them to pile up into a shock wave.

    In 2015 in Nature Physics, the ACSEL team reported a glimpse of the Weibel instability in an experiment at OMEGA. The researchers spotted magnetic fields, but didn’t directly detect the filaments of current. Finally, this year, in the May 29 Physical Review Letters, the team reported that a new experiment had produced the first direct measurements of the currents that form as a result of the Weibel instability, confirming scientists’ ideas about how strong magnetic fields could form in supernova remnants.

    For that new experiment, also at OMEGA, ACSEL researchers blasted seven lasers each at two targets facing each other. That resulted in two streams of plasma flowing toward each other at up to 1,500 kilometers per second — a speed fast enough to circle the Earth twice in less than a minute. When the two streams met, they separated into filaments of current, just as expected, producing magnetic fields of 30 tesla, about 20 times the strength of the magnetic fields in many MRI machines.

    “What we found was basically this textbook picture that has been out there for 60 years, and now we finally were able to see it experimentally,” Fiuza says.

    Surfing a shock wave

    Once the researchers had seen magnetic fields, the next step was to create a shock wave and to observe it accelerating particles. But, Park says, “no matter how much we tried on OMEGA, we couldn’t create the shock.”

    They needed the National Ignition Facility and its bigger laser.

    There, the researchers hit two disk-shaped targets with 84 laser beams each, or nearly half a million joules of energy, about the same as the kinetic energy of a car careening down a highway at 60 miles per hour.

    Two streams of plasma surged toward each other. The density and temperature of the plasma rose where the two collided, the researchers reported in the September Nature Physics. “No doubt about it,” Park says. The group had seen a shock wave, specifically the collisionless type found in supernovas. In fact there were two shock waves, each moving away from the other.

    4
    Credit: F. Fiuza et al/Nature Physics 2020.

    Learning the results sparked a moment of joyous celebration, Park says: high fives to everyone.

    “This is some of the first experimental evidence of the formation of these collisionless shocks,” says plasma physicist Francisco Suzuki-Vidal of Imperial College London, who was not involved in the study. “This is something that has been really hard to reproduce in the laboratory.”

    The team also discovered that electrons had been accelerated by the shock waves, reaching energies more than 100 times as high as those of particles in the ambient plasma. For the first time, scientists had watched particles surfing shock waves like the ones found in supernova remnants.

    But the group still didn’t understand how that was happening.

    In a supernova remnant and in the experiment, a small number of particles are accelerated when they cross over the shock wave, going back and forth repeatedly to build up energy. But to cross the shock wave, the electrons need some energy to start with. It’s like a big-wave surfer attempting to catch a massive swell, Fiuza says. There’s no way to catch such a big wave by simply paddling. But with the energy provided by a Jet Ski towing surfers into place, they can take advantage of the wave’s energy and ride the swell.

    4
    A computer simulation of a shock wave (structure shown in blue) illustrates how electrons gain energy (red tracks are higher energy, yellow and green are lower).Credit: F. Fiuza/SLAC National Accelerator Laboratory.

    “What we are trying to understand is: What is our Jet Ski? What happens in this environment that allows these tiny electrons to become energetic enough that they can then ride this wave and be accelerated in the process?” Fiuza says.

    The researchers performed computer simulations that suggested the shock wave has a transition region in which magnetic fields become turbulent and messy. That hints that the turbulent field is the Jet Ski: Some of the particles scatter in it, giving them enough energy to cross the shock wave.

    Wake-up call

    Enormous laser facilities such as NIF and OMEGA are typically built to study nuclear fusion — the same source of energy that powers the sun. Using lasers to compress and heat a target can cause nuclei to fuse with one another, releasing energy in the process. The hope is that such research could lead to fusion power plants, which could provide energy without emitting greenhouse gases or dangerous nuclear waste (SN: 4/20/13, p. 26). But so far, scientists have yet to get more energy out of the fusion than they put in — a necessity for practical power generation.

    So these laser facilities dedicate many of their experiments to chasing fusion power. But sometimes, researchers like Park get the chance to study questions based not on solving the world’s energy crisis, but on curiosity — wondering what happens when a star explodes, for example. Still, in a roundabout way, understanding supernovas could help make fusion power a reality as well, as that celestial plasma exhibits some of the same behaviors as the plasma in fusion reactors.

    At NIF, Park has also worked on fusion experiments. She has studied a wide variety of topics since her grad school days, from working on the U.S. “Star Wars” missile defense program, to designing a camera for a satellite sent to the moon, to looking for the sources of high-energy cosmic light flares called gamma-ray bursts. Although she is passionate about each topic, “out of all those projects,” she says, “this particular collisionless shock project happens to be my love.”

    Early in her career, back on that experiment in the salt mine, Park got a first taste of the thrill of discovery. Even before IMB captured neutrinos from a supernova, a different unexpected neutrino popped up in the detector. The particle had passed through the entire Earth to reach the experiment from the bottom. Park found the neutrino while analyzing data at 4 a.m., and woke up all her collaborators to tell them about it. It was the first time anyone working on the experiment had seen a particle coming up from below. “I still clearly remember the time when I was seeing something nobody’s seen,” Park recalls.

    Now, she says, she still gets the same feeling. Screams of joy erupt when she sees something new that describes the physics of unimaginably vast explosions.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition


    Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration
    Lawrence Livermore National Laboratory (LLNL) is an American federal research facility in Livermore, California, United States, founded by the University of California, Berkeley in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System. In 2012, the laboratory had the synthetic chemical element livermorium named after it.
    LLNL is self-described as “a premier research and development institution for science and technology applied to national security.” Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.

    The Laboratory is located on a one-square-mile (2.6 km2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.

    LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence,[2] director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.

    The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined

     
  • richardmitnick 8:53 am on July 2, 2019 Permalink | Reply
    Tags: A team of scientists from Lawrence Livermore National Laboratory (LLNL) and Russia that discovered five elements from 1989 to 2010., “Astrophysicists also are interested in these types of reactions because of NIF’s ability to duplicate the conditions at the interior of stars” Shaughnessy said., , , NIF-National Ignition Facility, , , Synthetic elements- flerovium (atomic number 114) moscovium (115) livermorium (116) tennessine (117) and oganesson (118)   

    From Lawrence Livermore National Laboratory: Women in STEM- “Stellar reactions in a galaxy not so far, far away” Dawn Shaughnessy 

    From Lawrence Livermore National Laboratory

    July 1, 2019
    Anne M Stark
    stark8@llnl.gov
    925-422-9799

    1
    Dawn Shaughnessy examines a sample plate used to collect the nuclear reaction products produced when neutrons from fusion during a NIF shot bombard research materials. Photo by Jason Laurea/LLNL

    Few people over the course of history have had a hand in discovering an atomic element. Yet nuclear chemist Dawn Shaughnessy joined a team of scientists from Lawrence Livermore National Laboratory (LLNL) and Russia that discovered five elements from 1989 to 2010.

    Now she leads the Nuclear and Radiochemistry Group of the Physics and Life Sciences Directorate at LLNL and uses the National Ignition Facility (NIF) to generate some of the most extreme conditions in our solar system for high energy density experiments.

    2

    Russian scientist Alexander Yeremin (left), Dawn Shaughnessy, and former LLNL scientist John Wild stand in front of a particle separator from the U400 cyclotron at Russia’s Flerov Laboratory of Nuclear Reactions in 2003. The experiments by these researchers and their colleagues were used to investigate the nuclear properties of elements copernicium (atomic number 112) and flerovium (114). Courtesy of Dawn Shaughnessy

    “NIF is the brightest neutron source in the world, and we use it to produce nuclear reactions that are relevant to stockpile stewardship and nuclear forensics programs. The reactions cannot be done by using accelerators or other means,” said Shaughnessy, who also is serving a one-year appointment as scientific editor of the Laboratory’s Science & Technology Review.

    National Ignition Facility at LLNL

    Her first experience with NIF came before it was even operational. She joined a working group to determine whether nuclear science could be performed at NIF, and, if so, what types of diagnostics would be needed for making the measurements.

    “I was fascinated,” she said. “It was really cutting-edge stuff. You could make measurements in a plasma. No one else in the world was able to do that.”

    She began investigating how to make experimental platforms for studying the nuclear reactions of materials of interest, such as the elements nickel, yttrium and zirconium (see “Providing Data for Nuclear Detectives”). But only over the last couple of years did her team develop a technique capable of doping target capsules with these elements.

    Serving as the NIF target is a 2-millimeter-diameter capsule lined on the inner surface with extremely small amounts of the material (about 1016 atoms) and filled with deuterium and tritium (DT) gas. The neutrons produced by the DT fusion during the shot bombard the material and cause nuclear reactions to occur. The fusion energy blows the products of the reaction outward, and the resulting solid debris is collected by specialized diagnostic instruments so that important radiochemical characteristics, such as rates of reactions, can be evaluated back inside a laboratory.

    “Astrophysicists also are interested in these types of reactions because of NIF’s ability to duplicate the conditions at the interior of stars,” Shaughnessy said.

    By studying nuclear reactions within the star-like plasma generated by NIF, researchers can better explore nuclear synthesis, the stellar process that eventually creates heavier elements by fusing together lighter elements and particles. Sometimes this process, which is a progression of different nuclear reactions, must first create lighter elements before heavier ones can be created.

    One such nuclear reaction under investigation occurs inside a class of stars that have masses on the order of the sun. It has boron absorbing a proton to form beryllium and an alpha particle. This nuclear reaction illustrates the type of interactions between atoms and particles that interest nuclear chemists.

    As is true for so many of the projects at LLNL, the search for basic science understanding can yield big returns for other programs. Through the Discovery Science program, about 8 percent of NIF’s shots each year are dedicated to these types of experiments.

    “Everything we’ve done for Discovery Science ties exactly into the platforms that we are developing for the Stockpile Stewardship Program,” Shaughnessy said. “It has helped teach us how to dope capsules with materials, how to collect materials coming out of a shot and how to conduct various analyses.”

    But it is not just in the stellar cauldrons of stars in other galaxies where atomic concoctions are brewed. It happens right here in our solar system, without even having to escape Earth’s gravitational force. And from early on, this attracted Shaughnessy.

    “Einsteinium is my favorite element,” she said. “It doesn’t get enough credit because its chemistry is relatively ordinary. But I think it is really cool.”

    Her affinity toward einsteinium wells from her Ph.D. research at the University of California, Berkeley, into the fission of this synthetic, radioactive element. But after graduation, she turned in the opposite direction at Lawrence Berkeley National Laboratory by studying environmental factors of plutonium, which she feels is one of the most interesting elements because it has many oxidation states and forms, and neptunium, plutonium’s next-door neighbor on the periodic table.

    This radioactive background is what led Shaughnessy to join LLNL’s Stockpile Radiochemistry Group in 2002, which is the same year she began hunting for elements that had never been observed before. The five elements that the team discovered were forged in a particle accelerator at Flerov Laboratory of Nuclear Reactions in Russia.

    “The heavy element program at the Lab was very small,” said Shaughnessy, who became the team’s principal investigator in 2005. “It was a team effort by people who were really dedicated to the science. Most of us had a background in it from somewhere else.”

    They filled out the bottom row of the periodic table by co-discovering the heavy elements flerovium (atomic number 114), moscovium (115), livermorium (116), tennessine (117) and oganesson (118) (see “Collaboration Expands the Periodic Table, One Element at a Time”).

    If any of these short-lived, synthetic elements have familiar sounding names, like livermorium, it might be because many elements that appear in the latter part of the periodic table are given names to honor people and places connected to important achievements in science.

    Periodic table Sept 2017. Wikipedia

    Shaughnessy recalls that the name davincium was tossed around during this period of discovery, and she hopes it will be used one day in commemoration of the early days of scientific investigation.

    It is hard not to envision Leonardo da Vinci, sketching his latest invention on a table while his Italian robe flowed around him. Shaughnessy, however, looked in a much more futuristic direction for her wardrobe inspiration: she owns a custom-made Jedi robe from a Jedi robe shop in England.

    “I am an enormous fan of ‘Star Wars,’” she said — no surprise to anyone who has worked with her. “I’ve been a fan since it first came out in 1977, when I saw it in a theater and connected with it at a young age. ‘Star Wars’ has always been a part of me. I still have my Star Wars figures. And now that we have new Star Wars movies again, I can get to share it with my daughter. I’ve probably seen the movies hundreds of times by this point.”

    Even at NIF, the force is strong with Shaughnessy. The influence runs deep. When trying to name a newly developed solid debris collecting diagnostic — which happens to look spaceship-like — she came up with Vast Area Detector for Experimental Radiochemistry, or VADER. She quickly points out, though, that she is of course aligned with the light side of the force — or, as in this case, the “laser light side.”

    Shaughnessy’s passion for this epic science fiction saga has helped propel her to transcend real-world boundaries, where science is fact and breakthroughs bring distant worlds much closer to home.

    —Dan Linehan

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    LLNL Campus

    Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration
    Lawrence Livermore National Laboratory (LLNL) is an American federal research facility in Livermore, California, United States, founded by the University of California, Berkeley in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System. In 2012, the laboratory had the synthetic chemical element livermorium named after it.
    LLNL is self-described as “a premier research and development institution for science and technology applied to national security.” Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.

    The Laboratory is located on a one-square-mile (2.6 km2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.

    LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence,[2] director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.

    The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined thermonuclear reactions (i.e. fusion). About half an hour southeast of Berkeley, the Livermore site provided much greater security for classified projects than an urban university campus.

    Lawrence tapped 32-year-old Herbert York, a former graduate student of his, to run Livermore. Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the Los Alamos and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence “big science” approach, tackling challenging projects with physicists, chemists, engineers, and computational scientists working together in multidisciplinary teams. Lawrence died in August 1958 and shortly after, the university’s board of regents named both laboratories for him, as the Lawrence Radiation Laboratory.

    Historically, the Berkeley and Livermore laboratories have had very close relationships on research projects, business operations, and staff. The Livermore Lab was established initially as a branch of the Berkeley laboratory. The Livermore lab was not officially severed administratively from the Berkeley lab until 1971. To this day, in official planning documents and records, Lawrence Berkeley National Laboratory is designated as Site 100, Lawrence Livermore National Lab as Site 200, and LLNL’s remote test location as Site 300.[3]

    The laboratory was renamed Lawrence Livermore Laboratory (LLL) in 1971. On October 1, 2007 LLNS assumed management of LLNL from the University of California, which had exclusively managed and operated the Laboratory since its inception 55 years before. The laboratory was honored in 2012 by having the synthetic chemical element livermorium named after it. The LLNS takeover of the laboratory has been controversial. In May 2013, an Alameda County jury awarded over $2.7 million to five former laboratory employees who were among 430 employees LLNS laid off during 2008.[4] The jury found that LLNS breached a contractual obligation to terminate the employees only for “reasonable cause.”[5] The five plaintiffs also have pending age discrimination claims against LLNS, which will be heard by a different jury in a separate trial.[6] There are 125 co-plaintiffs awaiting trial on similar claims against LLNS.[7] The May 2008 layoff was the first layoff at the laboratory in nearly 40 years.[6]

    On March 14, 2011, the City of Livermore officially expanded the city’s boundaries to annex LLNL and move it within the city limits. The unanimous vote by the Livermore city council expanded Livermore’s southeastern boundaries to cover 15 land parcels covering 1,057 acres (4.28 km2) that comprise the LLNL site. The site was formerly an unincorporated area of Alameda County. The LLNL campus continues to be owned by the federal government.

    LLNL/NIF


    DOE Seal
    NNSA

     
  • richardmitnick 7:58 pm on July 16, 2018 Permalink | Reply
    Tags: , , , NIF-National Ignition Facility, , , Rayleigh-Taylor (RT) instabilities, Richtmyer-Meshkov instability   

    From Lawrence Livermore National Laboratory: “Researchers work to advance understanding of hydrodynamic instabilities in NIF, astrophysics” 

    From Lawrence Livermore National Laboratory

    July 16, 2018
    Breanna Bishop
    bishop33@llnl.gov
    925-423-9802

    1
    A simulation of Rayleigh-Taylor (RT) hydrodynamic instability created on Lawrence Livermore National Laboratory’s BlueGene/L supercomputer using the MIRANDA code. RT instability occurs when a light fluid accelerates a heavier fluid and is a fundamental fluid-mixing mechanism important to inertial confinement fusion applications, star formation dynamics, supernova explosions, planetary formation dynamics and asteroid impact dynamics.

    LLNL Vulcan IBM Blue GeneQ system supercomputer

    In a Proceedings of the National Academy of Sciences (PNAS) “Special Feature” paper published online June 26, Lawrence Livermore National Laboratory (LLNL) and University of Michigan researchers reported on recent experiments and techniques designed to improve understanding and control of hydrodynamic (fluid) instabilities in high energy density (HED) settings such as those that occur in inertial confinement fusion implosions on the National Ignition Facility (NIF).

    This paper described four areas of HED research that focus on Rayleigh-Taylor (RT) instabilities, which arise when two fluids or plasmas of different densities are accelerated together, with the lighter (lower density) fluid pushing and accelerating the heavier (higher density) fluid.

    These instabilities can degrade NIF implosion performance because they amplify target defects as well as perturbations caused by engineering features like the “tents” used to suspend the target capsule in the hohlraum and the fill tube that injects fusion fuel into the capsule.

    Conversely, RT and its shock analog, the Richtmyer-Meshkov instability, are seen when stellar explosions (supernovae) eject their core material, such as titanium, iron and nickel, into interstellar space. The material penetrates through and outruns the outer envelopes of the lighter elements of silicon, oxygen, carbon, helium and hydrogen. In addition, a unique regime of HED solid-state plastic flow and hydrodynamic instabilities can occur in the dynamics of planetary formation and asteroid and meteor impacts.

    The PNAS paper presents summaries of studies of a wide range of HED RT instabilities that are relevant to astrophysics, planetary science, hypervelocity impact dynamics and inertial confinement fusion (ICF).

    The researchers said the studies, while aimed primarily at improving understanding of stabilization mechanisms in RT growth on NIF implosions, also offer “unique opportunities to study phenomena that typically can be found only in high-energy astrophysics, astronomy and planetary science,” such as the interiors of planets and stars, the dynamics of planetary formation, supernovae, cosmic gamma-ray bursts and galactic mergers.

    NIF HED experiments can generate pressures up to 100 terapascals (one billion atmospheres). These extreme conditions allow research samples to be driven, or compressed, to the kinds of pressures found in planetary interiors and the interiors of brown dwarfs (sometimes called “failed stars”). They also lend themselves to studies of RT evolution ranging from hot, dense plasmas and burning hot spots at the center of ICF implosions to relatively cool, high-pressure materials undergoing solid-state plastic flow at high strain and strain rate.

    “We found that the material strength in these high-pressure, solid-state, high-strain-rate plastic flow experiments is large and can significantly reduce the RT growth rates compared with classical values,” the researchers said. “These results are relevant to planetary formation dynamics at high pressures.”

    “An intriguing consideration,” they added, “is the possibility of using these findings to enhance resistance to hydrodynamic instabilities in advanced designs of ICF capsule implosions.”

    Joining lead author Bruce Remington on the paper were LLNL colleagues Hye-Sook Park, Dan Casey, Rob Cavallo, Dan Clark, Channing Huntington, Aaron Miles, Sabrina Nagel, Kumar Raman and Vladimir Smalyuk, along with Carolyn Kuranz of the University of Michigan.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    LLNL Campus

    Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration
    Lawrence Livermore National Laboratory (LLNL) is an American federal research facility in Livermore, California, United States, founded by the University of California, Berkeley in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System. In 2012, the laboratory had the synthetic chemical element livermorium named after it.

    LLNL is self-described as “a premier research and development institution for science and technology applied to national security.”[1] Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.

    The Laboratory is located on a one-square-mile (2.6 km2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.

    LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence,[2] director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.

    The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined thermonuclear reactions (i.e. fusion). About half an hour southeast of Berkeley, the Livermore site provided much greater security for classified projects than an urban university campus.

    Lawrence tapped 32-year-old Herbert York, a former graduate student of his, to run Livermore. Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the Los Alamos and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence “big science” approach, tackling challenging projects with physicists, chemists, engineers, and computational scientists working together in multidisciplinary teams. Lawrence died in August 1958 and shortly after, the university’s board of regents named both laboratories for him, as the Lawrence Radiation Laboratory.

    Historically, the Berkeley and Livermore laboratories have had very close relationships on research projects, business operations, and staff. The Livermore Lab was established initially as a branch of the Berkeley laboratory. The Livermore lab was not officially severed administratively from the Berkeley lab until 1971. To this day, in official planning documents and records, Lawrence Berkeley National Laboratory is designated as Site 100, Lawrence Livermore National Lab as Site 200, and LLNL’s remote test location as Site 300.[3]

    The laboratory was renamed Lawrence Livermore Laboratory (LLL) in 1971. On October 1, 2007 LLNS assumed management of LLNL from the University of California, which had exclusively managed and operated the Laboratory since its inception 55 years before. The laboratory was honored in 2012 by having the synthetic chemical element livermorium named after it. The LLNS takeover of the laboratory has been controversial. In May 2013, an Alameda County jury awarded over $2.7 million to five former laboratory employees who were among 430 employees LLNS laid off during 2008.[4] The jury found that LLNS breached a contractual obligation to terminate the employees only for “reasonable cause.”[5] The five plaintiffs also have pending age discrimination claims against LLNS, which will be heard by a different jury in a separate trial.[6] There are 125 co-plaintiffs awaiting trial on similar claims against LLNS.[7] The May 2008 layoff was the first layoff at the laboratory in nearly 40 years.[6]

    On March 14, 2011, the City of Livermore officially expanded the city’s boundaries to annex LLNL and move it within the city limits. The unanimous vote by the Livermore city council expanded Livermore’s southeastern boundaries to cover 15 land parcels covering 1,057 acres (4.28 km2) that comprise the LLNL site. The site was formerly an unincorporated area of Alameda County. The LLNL campus continues to be owned by the federal government.

    LLNL/NIF


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  • richardmitnick 1:24 pm on May 2, 2018 Permalink | Reply
    Tags: ELI Beamlines facility, , , NIF-National Ignition Facility   

    From Lawrence Livermore National Laboratory: “Lasers, photonics and powerful partnerships” 

    Lawrence Livermore National Laboratory

    April 30, 2018

    Stephen Wampler
    wampler1@llnl.gov
    925-423-3107

    1
    The commercialization of laser peening technology — similar to working a metal’s surface with a ballpeen hammer — has been one of the most successful transfers of Lawrence Livermore technology to industry. The laser peening technology, which was originally developed by Battelle in the 1970s and was first commercialized by LSP technologies in 1975, was upgraded by LLNL researchers working with Metal Improvement Co. Inc.

    The world’s most energetic laser sits in a secure, guarded federal laboratory, but its impact stretches far beyond the one-square-mile site of Lawrence Livermore National Laboratory (LLNL).


    National Ignition Facility at LLNL

    Since the outset, technologies developed or improved at the Laboratory have led to industry-defining partnerships and products that make millions of Americans’ lives better every day. Even if they’ve never heard of them.

    “Nearly all of us at this point have flown on an airplane with turbine blades that were laser peened with technology that Livermore commercialized years ago,” said Craig Siders, senior scientist and commercial technology development leader in NIF & Photon Science’s Advanced Photon Technologies program. Laser peening — using intense laser light to improve the quality of a material — had been invented in the 1970s, but had not achieved significant market penetration until LLNL introduced a new laser architecture that provided critical new functionality to the technology. Laser peening is commonplace now, thanks in part to Laboratory research that was spun off into the private sector.

    “It’s technology that’s absolutely in the hands of industry today, and the Lab is now out of the peening business, because it’s the right thing to do,” Siders added. “LLNL’s innovations in laser technology were a critical component in making peening a success story.”

    In 2003, former LLNL scientists Lloyd Hackel and Brent Dane, together with LLNL CRADA partner Metal Improvement Company (MIC), today part of Curtiss-Wright Corporation, brought the benefits of laser peening to the economy as a whole. The Laboratory’s commercialization process worked: Lawrence Livermore helped develop a cutting-edge technology until it was mature enough to stand on its own. Today, laser peening can exponentially extend the lifespan of an F-22 fighter jet’s airframe. MIC has treated jet engine fan blades on every Airbus A340 passenger plane and hundreds of Boeing 777s and 787s. It’s the third best royalty-producing technology in Lab history.

    And now, LLNL is offering the opportunity to license and commercialize an extension of laser-peening technology called high velocity laser accelerated deposition (HVLAD) for controlled laser-driven explosive bonding. HVLAD was selected by R&D Magazine as a winner of an R&D 100 Award in 2012.

    “We’re in the process of satisfying the primary goals of the Lab — pursuing national security, stockpile stewardship and fundamental science,” said David Dawes, a business development executive in LLNL’s Innovation and Partnerships Office (IPO). “All of these things can help generate spinoffs that are commercially important.”

    Dawes is a primary conduit between LLNL and industry. When scientists believe they have a breakthrough, they often come to Dawes for advice. Whether that conversation leads to a record of invention, a patent or a Collaborative Research and Development Agreement (CRADA), he’s instrumental in helping keep up with the laser and optics industry and matching research with opportunity. Many of NIF’s 40,000 brand new, specialized optical components represent commercialization opportunities, thanks to the new technologies developed to create them. As the Laboratory advances each dimension of laser and optics technology, companies can follow behind and adopt them as they become available.

    “All of these features involve leading-edge technologies that are important to the laser industry as a whole as they scale up their power levels,” Dawes says. “There’s marketable technologies there that we’re currently talking to a number of companies about licensing.” For other examples of current laser and optics technologies available for commercialization, see the IPO website.

    In particular, Dawes brings 35 years of experience in the industry (and some patents of his own) to bear on IPO’s work connecting research with companies. Maintaining long-standing relationships with industry and academic leaders, setting up visits to Livermore and monitoring trade and scientific journals are important tricks of Dawes’ trade. IPO screens every paper slated for journal publication in order to identify possibilities for future commercialization. Details on ongoing CRADAs and licensing are scarce, but the Laboratory’s track record speaks for itself.

    “The Lab has had a significant impact, historically, on the market,” said Siders. “There’s a lot of goodwill out there, built up with past success stories like peening.”

    Pushing the frontiers in lasers

    Anticipating the next generation of lasers is especially fertile ground for partnerships with LLNL’s NIF & Photon Science researchers. Scientists expect these lasers to be so powerful, current optics technologies won’t be able to withstand them.

    “When I was a professor, I called this the first law of directed energy,” said Siders. “Thou Shalt Destroy the Target Before You Destroy the Laser.”

    A current CRADA with Electro-Optics Technology (EOT) aims to address one of these. Known for their diode-like Faraday isolators — permitting light to pass in one direction only while preventing harmful backward propagation — EOT, among other industry leaders, got a call from Laboratory researchers with experience in high-power laser performance and component cooling looking for pushing the limits of isolator technologies. EOT was looking to advance applications of new materials, which fit perfectly into the needs for high-power isolators. Together, EOT and LLNL are close to producing a marketable product that will benefit the laser industry as a whole and prepare the Laboratory for advanced high-power laser systems.

    One such system is the new HAPLS pulsed-laser being installed in the European Union’s Extreme Light Infrastructure (ELI) Beamlines facility in the Czech Republic.

    The L3-HAPLS laser system, installed at the ELI Beamlines Research Center in Dolní Břežany, Czech Republic.

    HAPLS (the High-Repetition-Rate Advanced Petawatt Laser System designed, developed and delivered by LLNL) integrates a number of new, efficient, high-power laser and optical technologies that Siders believes will eventually lead to the lasers necessary for inertial fusion energy. It’s a powerful tool for its customer, ELI Beamlines, but it’s also a window for scientists into the future of high-power pulsed lasers and a possible fusion power plant.

    ELI Beamlines facility, Research Center in Dolní Břežany, Czech Republic

    2
    LLNL researchers partnered with Lasertel Inc. to develop the world’s highest peak power laser diode arrays, representing total peak power of 3.2 megawatts, to power the High-Repetition-Rate Advanced Petawatt Laser System. To drive the diode arrays, LLNL developed and patented a new type of pulsed-power system, which supplies the arrays with electrical power by drawing energy from the grid and converting it to extremely high-current, precisely-shaped electrical pulses. Photo by Damien Jemison/LLNL.

    “We’re actually looking to provide benefits back from investments that this nation and the Department of Energy have made over four or five decades of research into inertial confinement fusion and inertial fusion energy,” said Siders. While luck is always a component, he added that strategy and ongoing communication are key to maintaining fruitful partnerships.

    “By working with industry in that way, we can get products on the market that everyone can benefit from,” said Siders. “That helps move the nation’s laser technology capabilities forward. That’s a good news story.”

    In addition to the significant benefits Lawrence Livermore’s laser and optics research can provide to industry, commercialization can also have a tremendous impact on the scientists themselves.

    “I often tell folks here that there’s a future where they could walk into almost any lab in the world, point to something and say ‘hey, that’s my work,’” said Siders. “That’s immensely rewarding.”

    -Ben Kennedy

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration

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  • richardmitnick 4:47 pm on April 17, 2018 Permalink | Reply
    Tags: , , NIF-National Ignition Facility, Ramp compression, Superearths   

    From Lawrence Livermore National Laboratory: “Ramp compression of iron provides insight into core conditions of large rocky exoplanets” 

    Lawrence Livermore National Laboratory

    April 16, 2018
    Breanna Bishop
    bishop33@llnl.gov
    925-423-9802

    1
    High-power lasers at the National Ignition Facility are focused onto a multi-stepped iron sample at the center of the 10-meter-diameter target chamber. These experiments measure the equation of state of iron under core conditions of large rocky exoplanets.

    In a paper published today by Nature Astronomy , a team of researchers from Lawrence Livermore National Laboratory (LLNL), Princeton University, Johns Hopkins University and the University of Rochester have provided the first experimentally based mass-radius relationship for a hypothetical pure iron planet at super-Earth core conditions.

    This discovery can be used to evaluate plausible compositional space for large, rocky exoplanets, forming the basis of future planetary interior models, which in turn can be used to more accurately interpret observation data from the Kepler space mission and aid in identifying planets suitable for habitability.

    “The discovery of large numbers of planets outside our solar system has been one of the most exciting scientific discoveries of this generation,” said Ray Smith, a physicist at LLNL and lead author of the research. “These discoveries raise fundamental questions. What are the different types of extrasolar planets and how do they form and evolve? Which of these objects can potentially sustain surface conditions suitable for life? To address such questions, it is necessary to understand the composition and interior structure of these objects.”

    Of the more than 4,000 confirmed and candidate extrasolar planets, those that are one to four times the radius of the Earth are now known to be the most abundant. This size range, which spans between Earth and Neptune, is not represented in our own solar system, indicating that planets form over a wider range of physical conditions than previously thought.

    “Determining the interior structure and composition of these super-Earth planets is challenging but is crucial to understanding the diversity and evolution of planetary systems within our galaxy,” Smith said.

    As core pressures for even a 5×-Earth-mass planet can reach as high as 2 million atmospheres, a fundamental requirement for constraining exoplanetary composition and interior structure is an accurate determination of the material properties at extreme pressures. Iron (Fe) is a cosmochemically abundant element and, as the dominant constituent of terrestrial planetary cores, is a key material for studying super-Earth interiors. A detailed understanding of the properties of iron at super-Earth conditions is an essential component of the team’s experiments.

    The researchers describe a new generation of high-power laser experiments, which use ramp compression techniques to provide the first absolute equation of state measurements of Fe at the extreme pressure and density conditions found within super-Earth cores. Such shock-free dynamic compression is uniquely suited for compressing matter with minimal heating to TPa pressures (1 TPa = 10 million atmospheres).

    The experiments were conducted at the LLNL’s National Ignition Facility (NIF).

    NIF, the world’s largest and most energetic laser, can deliver up to 2 megajoules of laser energy over 30 nanoseconds and provides the necessary laser power and control to ramp compress materials to TPa pressures. The team’s experiments reached peak pressures of 1.4 TPa, four times higher pressure than previous static results, representing core conditions found with a 3-4x Earth mass planet.

    “Planetary interior models, which rely on a description of constituent materials under extreme pressures, are commonly based on extrapolations of low-pressure data and produce a wide range of predicated material states. Our experimental data provides a firmer basis for establishing the properties of a super-Earth planet with a pure iron planet,” Smith said. “Furthermore, our study demonstrates the capability for determination of equations of state and other key thermodynamic properties of planetary core materials at pressures well beyond those of conventional static techniques. Such information is crucial for advancing our understanding of the structure and dynamics of large rocky exoplanets and their evolution.”

    Future experiments on NIF will extend the study of planetary materials to several TPa while combining nanosecond X-ray diffraction techniques to determine the crystal structure evolution with pressure.

    Co-authors include Dayne Fratanduono, David Braun, Peter Celliers, Suzanne Ali, Amalia Fernandez-Pañella, Richard Kraus, Damian Swift and Jon Eggert from LLNL; Thomas Duffy from Princeton University; June Wicks from Johns Hopkins University; and Gilbert Collins from the University of Rochester.
    Tags: Lasers / NIF / National Ignition Facility

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    LLNL Campus

    Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration

    LLNL/NIF


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