(Press-News.org) LIVERMORE, Calif. -- Researchers at Lawrence Livermore National Laboratory have performed record simulations using all 1,572,864 cores of Sequoia, the largest supercomputer in the world. Sequoia, based on IBM BlueGene/Q architecture, is the first machine to exceed one million computational cores. It also is No. 2 on the list of the world's fastest supercomputers, operating at 16.3 petaflops (16.3 quadrillion floating point operations per second).
The simulations are the largest particle-in-cell (PIC) code simulations by number of cores ever performed. PIC simulations are used extensively in plasma physics to model the motion of the charged particles, and the electromagnetic interactions between them, that make up ionized matter. High performance computers such as Sequoia enable these codes to follow the simultaneous evolution of tens of billions to trillions of individual particles in highly complex systems.
Frederico Fiuza, a physicist and Lawrence Fellow at LLNL, performed the simulations in order to study the interaction of ultra-powerful lasers with dense plasmas in a proposed method to produce fusion energy, the energy source that powers the sun, in a laboratory setting. The method, known as fast ignition, uses lasers capable of delivering more than a petawatt of power (a million billion watts) in a fraction of a billionth of a second to heat compressed deuterium and tritium (DT) fuel to temperatures exceeding the 50 million degrees Celsius needed to initiate fusion reactions and release net energy. The project is part of the U.S. Department of Energy's Office of Fusion Energy Science Program.
This method differs from the approach being taken by LLNL's National Ignition Facility to achieve thermonuclear ignition and burn. NIF's approach is called the "central hot spot" scenario, which relies on simultaneous compression and ignition of a spherical fuel capsule in an implosion, much like in a diesel engine. Fast ignition uses the same hardware as the hot spot approach but adds a high-intensity, ultrashort-pulse laser as the "spark" that achieves ignition.
The code used in these simulations was OSIRIS, a PIC code that has been developed over more than 10 years in collaboration between the University of California, Los Angeles and Portugal's Instituto Superior Técnico. Using this code, Fiuza demonstrated excellent scaling in parallel performance of OSIRIS to the full 1.6 million cores of Sequoia. By increasing the number of cores for a relatively small problem of fixed size, what computer scientists call "strong scaling," OSIRIS obtained 75 percent efficiency on the full machine. But when the total problem size was increased, what is called "weak scaling," a 97 percent efficiency was achieved.
"This means that a simulation that would take an entire year to perform on a medium-size cluster of 4,000 cores can be performed in a single day. Alternatively, problems 400 times greater in size can be simulated in the same amount of time," Fiuza said. "The combination of this unique supercomputer and this highly efficient and scalable code is allowing for transformative research."
OSIRIS is routinely used for fundamental science during the test phase of Sequoia in simulations with up to 256,000 cores. These simulations are allowing researchers, for the first time, to model the interaction of realistic fast-ignition-scale lasers with dense plasmas in three dimensions with sufficient speed to explore a large parameter space and optimize the design for ignition. Each simulation evolves the dynamics of more than 100 billion particles for more than 100,000 computational time steps. This is approximately an order of magnitude larger than the previous largest simulations of fast ignition.
Sequoia is a National Nuclear Security Administration (NNSA) machine, developed and fielded as part of NNSA's Advanced Simulation and Computing (ASC) program. Sequoia is in preparations to move to classified computing in support of stockpile stewardship.
"This historic calculation is an impressive demonstration of the power of high-performance computing to advance our scientific understanding of complex systems," said Bill Goldstein, LLNL's deputy director for Science and Technology. "With simulations like this, we can help transform the outlook for laboratory fusion as a tool for science, energy and stewardship of the nuclear stockpile."
###
Founded in 1952, Lawrence Livermore National Laboratory (http://www.llnl.gov) provides solutions to our nation's most important national security challenges through innovative science, engineering and technology. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.
END
(Boston) –Physician experts in health system issues propose a timely alternative process for harnessing and supporting physician-led innovations to rapidly address front-line health care delivery problems and improve health. Published as a Viewpoint article in the March 20th issue of the Journal of the American Medical Association (JAMA), the authors propose health systems adopt a strategy widely accepted in U.S. industries of "user-led" innovation.
User-led innovation is predicated on the idea that important enhancements to products and services are often made by users ...
BALTIMORE – March 19, 2013. Researchers at the University of Maryland School of Medicine have identified a peptide, or protein, derived from Pacific cod that may inhibit prostate cancer and possibly other cancers from spreading, according to preclinical research published online in the Proceedings of the National Academy of Sciences (PNAS).
"The use of natural dietary products with anti-tumor activity is an important and emerging field of research," says senior author Hafiz Ahmed, Ph.D., assistant professor of biochemistry and molecular biology at the University of Maryland ...
The U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) and Argonne National Laboratory (ANL) today announced the release of the Transportation Energy Futures (TEF) study, an assessment of avenues to reach deep cuts in petroleum use and greenhouse gas (GHG) emissions in the transportation sector.
"Transportation is an engine of our economic strength, but it also represents a key challenge for the future of U.S. energy use," NREL Senior Analyst Austin Brown said. "Transportation accounts for 71 percent of total U.S. petroleum consumption and 33 ...
OAK BROOK, Ill. – March 19, 2013 – In recognition of National Colorectal Cancer Awareness Month, GIE: Gastrointestinal Endoscopy has published a special issue for March on colorectal cancer. The issue includes a practical guide for approaching and managing serrated colon polyps, one of the most common types of polyps, and a study on reducing postpolypectomy bleeding with prophylactic clip closure. GIE: Gastrointestinal Endoscopy is the monthly peer-reviewed scientific journal of the American Society for Gastrointestinal Endoscopy (ASGE).
"The cutting edge of serrated ...
Nurses and midwives can play a critical role in lessening people's risk of cardiovascular diseases, cancers, chronic respiratory disease and diabetes, according to a groundbreaking new report issued by the World Health Organization and co-authored by a UCLA nursing professor.
These four non-communicable disease types account for a combined 60 percent of all deaths worldwide.
"The global burden of non-communicable diseases is already high and continues to grow in all regions of the world," said Linda Sarna, a professor at the UCLA School of Nursing and co-author ...
SAN FRANCISCO, CA (March 19, 2013) - House paint containing dangerous
concentrations of lead is being sold in Cameroon by an American company – and the
company is refusing to remove the paint from store shelves.
"There is an immediate need for regulations to restrict the lead content of paint in
Cameroon to protect public health," said Perry Gottesfeld, Executive Director of
Occupational Knowledge International (OK International) and co-author of a new
research study about this lead hazard.
"The levels of lead are extraordinarily high, and these products have been ...
MAYWOOD, Ill. – Findings from a Loyola University Chicago Stritch School of Medicine study could lead to the development of new drugs to treat gout.
The study, led by Liang Qiao, MD, and his colleagues and collaborators, was published March 19 in the journal Nature Communications.
Gout is caused by a buildup of uric acid around joints, typically the big toe, knee or ankles. The immune system revs up to attack uric acid salt crystals, and this immune response causes painful inflammation.
The innate immune response is mainly activated by calcium that enters a macrophage ...
SAN DIEGO — Neurologists at Mayo Clinic in Arizona have taken a promising step toward identifying a test that helps support the diagnosis of concussion. Their research has shown that autonomic reflex testing, which measures involuntary changes in heart rate and blood pressure, consistently appear to demonstrate significant changes in those with concussion. They presented the findings at the American Academy of Neurology annual meeting in San Diego this week.
Right now doctors rely primarily on self-reporting of symptoms to make a diagnosis of concussion. In addition, ...
PITTSBURGH—Women may be less likely to pursue careers in science—not because they have less ability—but because they have more career choices, according to a University of Pittsburgh study published today in Psychological Science.
Although the gender gap in mathematics has narrowed in recent decades between males and females, women are still less likely to pursue STEM careers than their male counterparts. Together with colleagues at the University of Michigan, the Pitt research team investigated whether differences in overall patterns of math and verbal ability might ...
Research led by a biology professor in the School of Science at Indiana University-Purdue University Indianapolis (IUPUI) has uncovered a method to produce retinal cells from regenerative human stem cells without the use of animal products, proteins or other foreign substances, which historically have limited the application of stem cells to treat disease and other human developmental disorders.
The study of human induced pluripotent stem cells (hiPSCs) has been pursued vigorously since they were first discovered in 2007 due to their ability to be manipulated into specific ...
