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  • 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

    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 .


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    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.


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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

    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

    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.

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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

    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.

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    Stem Education Coalition
    LLNL Campus

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


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