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Machine Learning Dramatically Streamlines Search for More Efficient Chemical Reactions

A catalytic reaction may follow thousands of possible paths, and it can take years to identify which one it actually takes so scientists can tweak it and make it more efficient. Now researchers at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University have taken a big step toward cutting through this thicket of possibilities.

Freezing Lithium Batteries May Make Them Safer and Bendable

Columbia Engineering Professor Yuan Yang has developed a new method that could lead to lithium batteries that are safer, have longer battery life, and are bendable, providing new possibilities such as flexible smartphones. His new technique uses ice-templating to control the structure of the solid electrolyte for lithium batteries that are used in portable electronics, electric vehicles, and grid-level energy storage. The study is published online April 24 in Nano Letters.

New Study Reveals the Mystery Behind the Formation of Hollowed Nanoparticles During Metal Oxidation

In a newly published <i>Science</i> paper, Argonne and Temple University researchers reveal new knowledge about the behavior of metal nanoparticles when they undergo oxidation, by integrating X-ray imaging and computer modeling and simulation. This knowledge adds to our understanding of fundamental processes like oxidation and corrosion.

Rare Supernova Discovery Ushers in New Era for Cosmology

With help from a supernova-hunting pipeline based at NERSC, astronomers captured multiple images of a gravitationally lensed Type 1a supernova. This is currently the only one, but if astronomers can find more they may be able to measure Universal expansion within four percent accuracy. Luckily, Berkeley Lab researchers do have a method for finding more.

Making Batteries From Waste Glass Bottles

Researchers at the University of California, Riverside's Bourns College of Engineering have used waste glass bottles and a low-cost chemical process to create nanosilicon anodes for high-performance lithium-ion batteries. The batteries will extend the range of electric vehicles and plug-in hybrid electric vehicles, and provide more power with fewer charges to personal electronics like cell phones and laptops.

Changing the Game

High performance computing researcher Shuaiwen Leon Song asked if hardware called 3D stacked memory could do something it was never designed to do--help render 3D graphics.

A Scientific Advance for Cool Clothing: Temperature-Wise, That Is

Stanford University researchers, with the aid of the Comet supercomputer at the San Diego Supercomputer at UC San Diego, have engineered a low-cost plastic material that could become the basis for clothing that cools the wearer, reducing the need for energy-consuming air conditioning.

Adjusting Solar Panel Angles a Few Times a Year Makes Them More Efficient

With Earth Day approaching, new research from Binghamton University-State of New York could help U.S. residents save more energy, regardless of location, if they adjust the angles of solar panels four to five times a year.

A Real CAM-Do Attitude

A multi-institutional team used resources at the Oak Ridge Leadership Computing Facility to catalog how desert plants photosynthetic processes vary. The study could help scientists engineer drought-resistant crops for food and fuel.

Predictive Power

The Consortium for Advanced Simulation of Light Water Reactors carried out the largest time-dependent simulation of a nuclear reactor ever to support Tennessee Valley Authority and Westinghouse Electric Company during the startup of Watts Bar Unit 2, the first new US nuclear reactor in 20 years. The simulation was carried out primarily on OLCF resources.


3 Small Energy Firms to Collaborate with PNNL

Pacific Northwest National Laboratory is collaborating with three small businesses to address technical challenges concerning hydrogen for fuel cell cars, bio-coal and nanomaterial manufacturing.

ORNL to Collaborate with Five Small Businesses to Advance Energy Tech

Five small companies have been selected to partner with the Department of Energy's Oak Ridge National Laboratory to move technologies in commercial refrigeration systems, water power generation, bioenergy and battery manufacturing closer to the marketplace.

U.S. Department of Energy's INCITE Program Seeks Advanced Computational Research Proposals for 2018

The Department of Energy's INCITE program will be accepting proposals for high-impact, computationally intensive research campaigns in a broad array of science, engineering, and computer science domains.

New Berkeley Lab Project Turns Waste Heat to Electricity

A new Berkeley Lab project seeks to efficiently capture waste heat and convert it to electricity, potentially saving California up to $385 million per year. With a $2-million grant from the California Energy Commission, Berkeley Lab scientists will work with Alphabet Energy to create a cost-effective thermoelectric waste heat recovery system.

New SLAC Theory Institute Aims to Speed Research on Exotic Materials at Light Sources

A new institute at the Department of Energy's SLAC National Accelerator Laboratory is using the power of theory to search for new types of materials that could revolutionize society - by making it possible, for instance, to transmit electricity over power lines with no loss.

Lenvio Inc. Exclusively Licenses ORNL Malware Behavior Detection Technology

Virginia-based Lenvio Inc. has exclusively licensed a cyber security technology from the Department of Energy's Oak Ridge National Laboratory that can quickly detect malicious behavior in software not previously identified as a threat.

Argonne Scientist and Nobel Laureate Alexei Abrikosov Dies at 88

Alexei Abrikosov, an acclaimed physicist at the U.S. Department of Energy's Argonne National Laboratory who received the 2003 Nobel Prize in Physics for his work on superconducting materials, died Wednesday, March 29. He was 88.

Jefferson Lab Accomplishes Critical Milestones Toward Completion of 12 GeV Upgrade

The Continuous Electron Beam Accelerator Facility (CEBAF) at the U.S. Department of Energy's Thomas Jefferson National Accelerator Facility has achieved two major commissioning milestones and is now entering the final stretch of work to conclude its first major upgrade. Recently, the CEBAF accelerator delivered electron beams into two of its experimental halls, Halls B and C, at energies not possible before the upgrade for commissioning of the experimental equipment currently in each hall. Data were recorded in each hall, which were then confirmed to be of sufficient quality to allow for particle identification, a primary indicator of good detector operation.

Valerie Taylor Named Argonne National Laboratory's Mathematics and Computer Science Division Director

Computer scientist Valerie Taylor has been appointed as the next director of the Mathematics and Computer Science division at Argonne, effective July 3, 2017.

Three SLAC Employees Awarded Lab's Highest Honor

At a March 7 ceremony, three employees of the Department of Energy's SLAC National Accelerator Laboratory were awarded the lab's highest honor ­- the SLAC Director's Award.


The Roadmap to Quark Soup

Scientists discover new signposts in the quest to determine how matter from the early universe turned into the world we know today.

Neutrons Play the Lead to Protons in Dance Around "Double-Magic" Nucleus

Electric and magnetic properties of a radioactive atom provide unique insight into the nature of proton and neutron motion.

Ultrafast Imaging Reveals the Electron's New Clothes

Scientists use high-speed electrons to visualize "dress-like" distortions in the atomic lattice. This work reveals the vital role of electron-lattice interactions in manganites. This material could be used in data-storage devices with increased data density and reduced power requirements.

One Small Change Makes Solar Cells More Efficient

For years, scientists have explored using tiny drops of designer materials, called quantum dots, to make better solar cells. Adding small amounts of manganese decreases the ability of quantum dots to absorb light but increases the current produced by an average of 300%.

Electronic "Cyclones" at the Nanoscale

Through highly controlled synthesis, scientists controlled competing atomic forces to let spiral electronic structures form. These polar vortices can serve as a precursor to new phenomena in materials. The materials could be vital for ultra-low energy electronic devices.

In a Flash! A New Way for Making Ceramics

A new process controllably but instantly consolidates ceramic parts, potentially important for manufacturing.

Deciphering Material Properties at the Single-Atom Level

Scientists determine the precise location and identity of all 23,000 atoms in a nanoparticle.

Smallest Transistor Ever

It has long been thought that building nanometer-sized transistors was impossible. Simply put, the physics and atomic structural imperfections couldn't be overcome. However, scientists built fully functional, nanometer-sized transistors.

Creation of Artificial Atoms

For the first time, scientists created a tunable artificial atom in graphene. The results from this research demonstrate a viable, controllable, and reversible technique to confine electrons in graphene.

Developing Tools to Understand Lithium-Ion Battery Instabilities

Scientists develop tools to understand Li-ion battery instabilities, enabling the study of electrodes and solid-electrolyte interphase formation.


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Great Neck South High School Wins Regional Science Bowl at Brookhaven Lab

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Middle Schoolers Test Their Knowledge at Science Bowl Competition

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Internship Program Helps Foster Development of Future Nuclear Scientists

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Scientists at PPPL Further Understanding of a Process That Causes Heat Loss in Fusion Devices

Article ID: 672571

Released: 2017-04-06 10:00:42

Source Newsroom: Princeton Plasma Physics Laboratory

  • Credit: Elle Starkman

    Physicist Angela Capece in PPPL's Surface Science and Technology Lab

  • Credit: Elle Starkman

    Physicist Angela Capece in PPPL's Surface Science and Technology Lab

  • Credit: Cesar Huerta

    Graduate student Marlene Patino in UCLA's Plasma and Space Propulsion Laboratory

Everyone knows that the game of billiards involves balls careening off the sides of a pool table — but few people may know that the same principle applies to fusion reactions. How charged particles like electrons and atomic nuclei that make up plasma interact with the walls of doughnut-shaped devices known as tokamaks helps determine how efficiently fusion reactions occur. Specifically, in a phenomenon known as secondary electron emission (SEE), electrons strike the surface of the wall, causing other electrons to be emitted. Those secondary electrons cool the plasma’s edge and dampen the plasma’s overall performance.

Scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have been studying SEE for decades, and in the past year have made important advances that further their understanding. Most recently, two of the physicists — Marlene Patino, a graduate student at the University of California, Los Angeles, and Angela Capece, a professor at the College of New Jersey — have focused their efforts on researching how SEE is affected by different wall materials and structures. 

Understanding SEE is crucial because the behavior of the secondary electrons could affect the performance of future fusion machines. “When heat losses become large, the fusion machine is less able to produce power,” Capece said.

In her SEE research, Capece studied how electrons interacted with lithium, a wall material that could improve the ability of tokamaks to confine plasma. Other scientists interested in lithium have created computer models that simulate how lithium interacts with electrons from the plasma, but those models have not taken into account how easily lithium bonds with other trace elements in the plasma, like oxygen, to form new molecules like lithium oxide. Those new molecules interact with electrons differently than pure lithium would.

Specifically, when electrons strike lithium oxide on a tokamak wall, many more secondary electrons are released into the plasma than for non-lithium wall materials like tungsten and carbon. If a tokamak has a lining made of graphite, one electron striking it with a particular amount of energy may produce one secondary electron. On the other hand, if an electron with the same energy strikes a lining made of lithium oxide, from one to three secondary electrons could result.

This discrepancy is crucial. “When incorporating SEE into models of fusion devices, it is important to account for the reactivity of lithium and that it will form lithium oxide in a tokamak environment,” Capece said.

Capece ultimately found that, in general, it becomes easier for an electron to release a secondary electron when the oxygen content in lithium linings rises. Her research quantified exactly how the amount of oxygen bound to the lithium in the wall changes the amount of secondary electrons that can enter the plasma. While an increased SEE yield could drive up heat loss, many variables at the edge of the plasma could modify the impact.

Patino studied SEE from a different perspective. She researched tiny structures, known as “fuzz,” that form on tungsten linings when they have been bombarded by helium nuclei. She observed that in comparison to smooth tungsten, tungsten with fuzz can reduce SEE by 40 percent to 60 percent. These findings were significant because past researchers’ studies involved manufactured microstructures, while in this study the tungsten fuzz grew by itself. Moreover, unlike with manufactured structures, the reduction of SEE does not depend on the angle at which the electrons approach the wall, both because the secondary electrons are trapped by the fuzz and the fibers in the fuzz are distributed randomly. “This lack of dependence on incident angle is important for walls in plasma machines since the electrons will impact the walls at large oblique angles,” Patino said.

Her work was published in the November 2016 issue of Applied Physics Letters. Capece’s was published in the July 2016 issue of the same journal. Their research was funded by the DOE’s Office of Science (Fusion Energy Sciences). Patino’s work also received funding from the Air Force Office of Scientific Research (AFOSR).

SEE first attracted the attention of PPPL scientists through both experimentation and theoretical research into plasma thrusters, devices that could one day propel spacecraft to distant cosmic objects. “PPPL researchers came up with the idea of using surface-architectured materials such as carbon velvet to suppress SEE and thereby improve the performance and longevity of the plasma thrusters,” said Yevgeny Raitses, a principal research physicist at PPPL and principal investigator on both Patino’s and Capece’s projects.

Previous SEE research at PPPL has involved a number of collaborators. These include PPPL principal investigators Raitses and Igor Kaganovich, together with Dr. Dmytro Sydorenko of the University of Alberta; Professor Andrei Smolyakov of the University of Saskatchewan; Professors Bruce Koel and Nat Fisch of Princeton University; and Professors Richard Wirz and Nasr Ghoniem of the University of California-Los Angeles. Their research has been funded by the AFOSR and the DOE’s Office of Science (Fusion Energy Sciences).

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