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Report Sheds New Insights on the Spin Dynamics of a Material Candidate for Low-Power Devices

In a report published in Nano LettersArgonne researchers reveal new insights into the properties of a magnetic insulator that is a candidate for low-power device applications; their insights form early stepping-stones towards developing high-speed, low-power electronics that use electron spin rather than charge to carry information.

Researchers Find Computer Code That Volkswagen Used to Cheat Emissions Tests

An international team of researchers has uncovered the mechanism that allowed Volkswagen to circumvent U.S. and European emission tests over at least six years before the Environmental Protection Agency put the company on notice in 2015 for violating the Clean Air Act. During a year-long investigation, researchers found code that allowed a car's onboard computer to determine that the vehicle was undergoing an emissions test.

Physicists Discover That Lithium Oxide on Tokamak Walls Can Improve Plasma Performance

A team of physicists has found that a coating of lithium oxide on the inside of fusion machines known as tokamaks can absorb as much deuterium as pure lithium can.

Scientists Perform First Basic Physics Simulation of Spontaneous Transition of the Edge of Fusion Plasma to Crucial High-Confinement Mode

PPPL physicists have simulated the spontaneous transition of turbulence at the edge of a fusion plasma to the high-confinement mode that sustains fusion reactions. The research was achieved with the extreme-scale plasma turbulence code XGC developed at PPPL in collaboration with a nationwide team.

Green Fleet Technology

New research at Penn State addresses the impact delivery trucks have on the environment by providing green solutions that keep costs down without sacrificing efficiency.

Scientists Demonstrate New Real-Time Technique for Studying Ionic Liquids at Electrode Interfaces

This electron microscope-based imaging technique could help scientists optimize the performance of ionic liquids for batteries and other energy storage devices.

How Scientists Turned a Flag Into a Loudspeaker

A paper-thin, flexible device created at Michigan State University not only can generate energy from human motion, it can act as a loudspeaker and microphone as well, nanotechnology researchers report in the May 16 edition of Nature Communications.

Assembling Life's Molecular Motor

As part of a project dedicated to modeling how single-celled purple bacteria turn light into food, a team of computational scientists from the University of Illinois at Urbana-Champaign (UIUC) simulated a complete ATP synthase in all-atom detail. The work builds on the project's first phase--a 100-million atom photosynthetic organelle called a chromatophore--and gives scientists an unprecedented glimpse into a biological machine whose energy efficiency far surpasses that of any artificial system.

Engineering Researchers Apply Data Science to Better Predict Effect of Weather and Other Conditions on Solar Panels

In a new study, a team of researchers from Case Western Reserve University and Gebze Technical University (GTU) in Turkey used data science to determine and predict the effects of exposure to weather and other conditions on materials in solar panels.

More Natural Dust in the Air Improves Air Quality in Eastern China

Man-made pollution in eastern China's cities worsens when less dust blows in from the Gobi Desert, according to a new study. That's because dust plays an important role in determining the air temperatures and thereby promoting winds to blow away man-made pollution. Less dust means the air stagnates, with man-made pollution sticking around longer.


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Rensselaer Polytechnic Institute Graduates Urged to Embrace Change at 211th Commencement

Describing the dizzying pace of technological innovation, former United States Secretary of Energy Ernest J. Moniz urged graduates to "anticipate career change, welcome it, and manage it to your and your society's benefit" at the 211th Commencement at Rensselaer Polytechnic Institute (RPI) Saturday.

ORNL Welcomes Innovation Crossroads Entrepreneurial Research Fellows

Oak Ridge National Laboratory today welcomed the first cohort of innovators to join Innovation Crossroads, the Southeast region's first entrepreneurial research and development program based at a U.S. Department of Energy national laboratory.

Department of Energy Secretary Recognizes Argonne Scientists' Work to Fight Ebola, Cancer

Two groups of researchers at Argonne earned special awards from the office of the U.S. Secretary of Energy for addressing the global health challenges of Ebola and cancer.

Jefferson Science Associates, LLC Recognized for Leadership in Small Business Utilization

Jefferson Lab/Jefferson Science Associates has a long-standing commitment to doing business with and mentoring small businesses. That commitment and support received national recognition at the 16th Annual Dept. of Energy Small Business Forum and Expo held May 16-18, 2017 in Kansas City, Mo.

Rensselaer Polytechnic Institute President's Commencement Colloquy to Address "Criticality, Incisiveness, Creativity"

To kick off the Rensselaer Polytechnic Institute Commencement weekend, the annual President's Commencement Colloquy will take place on Friday, May 19, beginning at 3:30 p.m. The discussion, titled "Criticality, Incisiveness, Creativity," will include the Honorable Ernest J. Moniz, former Secretary of Energy, and the Honorable Roger W. Ferguson Jr., President and CEO of TIAA, and will be moderated by Rensselaer President Shirley Ann Jackson.

ORNL, University of Tennessee Launch New Doctoral Program in Data Science

The Tennessee Higher Education Commission has approved a new doctoral program in data science and engineering as part of the Bredesen Center for Interdisciplinary Research and Graduate Education.

SurfTec Receives $1.2 Million Energy Award to Develop Novel Coating

The Department of Energy has awarded $1.2 million to SurfTec LLC, a company affiliated with the U of A Technology Development Foundation, to continue developing a nanoparticle-based coating to replace lead-based journal bearings in the next generation of electric machines.

Ames Laboratory Scientist Inducted Into National Inventors Hall of Fame

Iver Anderson, senior metallurgist at Ames Laboratory, has been inducted into the National Inventors Hall of Fame.

DOE HPC4Mfg Program Funds 13 New Projects to Improve U.S. Energy Technologies Through High Performance Computing

A U.S. Department of Energy (DOE) program designed to spur the use of high performance supercomputers to advance U.S. manufacturing is funding 13 new industry projects for a total of $3.9 million.

Penn State Wind Energy Club Breezes to Victory in Collegiate Wind Competition

The Penn State Wind Energy Club breezed through the field at the U.S. Department of Energy Collegiate Wind Competition 2017 Technical Challenge, held April 20-22 at the National Wind Technology Center near Boulder, Colorado--earning its third overall victory in four years at the Collegiate Wind Competition.


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Casting a Wide Net

Designed molecules will provide positive impacts in energy production by selectively removing unwanted ions from complex solutions.

New Software Tools Streamline DNA Sequence Design-and-Build Process

Enhanced software tools will accelerate gene discovery and characterization, vital for new forms of fuel production.

The Ultrafast Interplay Between Molecules and Materials

Computer calculations by the Center for Solar Fuels, an Energy Frontier Research Center, shed light on nebulous interactions in semiconductors relevant to dye-sensitized solar cells.

Supercapacitors: WOODn't That Be Nice

Researchers at Nanostructures for Electrical Energy Storage, an Energy Frontier Research Center, take advantage of nature-made materials and structure for energy storage research.

Groundwater Flow Is Key for Modeling the Global Water Cycle

Water table depth and groundwater flow are vital to understanding the amount of water that plants transmit to the atmosphere.

Finding the Correct Path

A new computational technique greatly simplifies the complex reaction networks common to catalysis and combustion fields.

Opening Efficient Routes to Everyday Plastics

A new material from the Inorganometallic Catalyst Design Center, an Energy Frontier Research Center, facilitates the production of key industrial supplies.

Fight to the Top: Silver and Gold Compete for the Surface of a Bimetallic Solid

It's the classic plot of a buddy movie. Two struggling bodies team up to drive the plot and do good together. That same idea, when it comes to metals, could help scientists solve a big problem: the amount of energy consumed by making chemicals.

Saving Energy Through Light Control

New materials, designed by researchers at the Center for Excitonics, an Energy Frontier Research Center, can reduce energy consumption with the flip of a switch.

Teaching Perovskites to Swim

Scientists at the ANSER Energy Frontier Research Center designed a two-component layer protects a sunlight-harvesting device from water and heat.


New Model of Plasma Stability Could Help Researchers Predict and Avoid Disruptions in Fusion Machines

Article ID: 674483

Released: 2017-05-10 15:05:27

Source Newsroom: Princeton Plasma Physics Laboratory

  • Credit: Elle Starkman

    Physicists Steve Sabbagh and Jack Berkery in front of the National Spherical Torus Experiment (NSTX-U)

  • Credit: Elle Starkman

    Physicist Steve Sabbagh

  • Credit: Elle Starkman

    Physicist Jack Berkery

Physicists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have helped develop a new computer model of plasma stability in doughnut-shaped fusion machines known as tokamaks. The new model incorporates recent findings gathered from related research efforts and simplifies the physics involved so computers can process the program more quickly. The model could help scientists predict when a plasma might become unstable and then avoid the underlying conditions.

This research was reported in a paper published in Physics of Plasmas in February 2017, and received funding from the DOE’s Office of Science (Fusion Energy Sciences).

The plasma stability code was written in part by Jack Berkery, a research scientist in the Applied Physics and Applied Mathematics Department at Columbia University who has been associated with PPPL for almost 10 years. He is working on this project with Steve Sabbagh, a senior research scientist and adjunct professor of applied physics at Columbia who has collaborated with PPPL for almost three decades. Both Berkery and Sabbagh are part of the Columbia group at PPPL.

The new research is the latest in the physicists’ combined effort to develop a larger and more capable plasma-stabilizing computer program known as the Disruption Event Characterization and Forecasting (DECAF) code that will predict and help avoid disruptions.

Within tokamak plasmas, many forces balance to create a stable equilibrium. One force is an expanding pressure created by the intrinsic properties of the plasma — a soup of electrically charged particles. Another force is produced by magnets that confine the plasma, preventing it from touching the tokamak’s inner walls and cooling down.

Plasma physicists and engineers want the plasma to be under as much magnetic pressure as possible, because high pressure means that the plasma particles are interacting more frequently, increasing both the chances that fusion reactions will occur and the amount of heat produced by the tokamak. Past research by Berkery and Sabbagh on machines including the National Spherical Torus Experiment-Upgrade (NSTX-U) at PPPL has shown that high plasma pressure can be contained in a stable way if other properties of the plasma, like the way in which it rotates, have particular characteristics.

“Ideally, you want to operate tokamaks at high pressure because to get good fusion performance, you want to have the highest pressure you can,” Berkery continued. “Unfortunately, when you do that, instabilities can arise. So if you can find a way to stabilize the plasma, then you can operate your tokamak at a higher pressure.”

The updated program was written to predict the conditions that would best contain the high-pressure plasma. The program, though, is only one component of the DECAF code, which includes many modules that each monitor different aspects of a plasma in an effort to determine when the plasma is becoming unstable. “For years, we’ve been investigating which conditions lead to instability and how we can try to avoid those conditions,” Berkery said.

The code gathers information that includes the plasma’s density, temperature, and the shape of the plasma’s rotation. It then calculates which combinations of these conditions produce a stable plasma, simultaneously uncovering which combinations of conditions produce an unstable plasma. The new code specifically looks for signs of an oncoming unstable state known as a resistive wall mode. A plasma enters this state when forces causing the plasma to expand are stronger than the forces confining the plasma. The plasma’s intrinsic magnetic fields then expand outward and strike the interior of the tokamak’s walls. 

Sabbagh, Berkery, and other researchers are now in the process of adding more modules to DECAF, increasing its ability to predict instabilities. They are also planning to use DECAF to help guide a rotation-control system on a tokamak like NSTX-U. The system would prevent the plasma from becoming unstable by producing stability-conducive plasma rotation profiles.

PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov