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  • richardmitnick 11:49 am on January 23, 2018 Permalink | Reply
    Tags: Elena Belova, PPPL, Theoretical physicist Elena Belova named to editorial board of Physics of Plasmas,   

    From PPPL: Women in STEM – “Theoretical physicist Elena Belova named to editorial board of Physics of Plasmas” 


    PPPL

    January 22, 2018
    John Greenwald

    1
    Elena Belova. (Photo by Elle Starkman/Office of Communications).

    Elena Belova, a principal research physicist in the Theory Department at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), has been named to the editorial board of the Physics of Plasmas, a monthly peer-reviewed scientific journal published by the American Institute of Physics. Duties of board members, selected for their high degree of technical expertise, range from suggesting topics for special sections to adjudicating impasses between authors and referees that arise over manuscripts.

    Belova, a PPPL physicist for more than 20 years, is expert at developing computer codes, such as simulations of wave-particle interactions and models of global stability in fusion plasmas that are widely used in fusion research. “I like code development because it is algorithmic and codes can really help to understand the experimental results,” she said. “But it still surprises me when theory works the way it’s supposed to. I also like that you can perform the simulation and look “inside” the device – which is not always possible in a real experiment. Visualizing things through computer simulations allows one to ‘see a picture,’ which is, as they say, better than a thousand words.”

    Fusing of light elements

    Fusion, the reaction that powers the sun and most stars, is the fusing of light elements that generates massive amounts of energy. Researchers seek to replicate fusion on Earth for a virtually inexhaustible supply of energy by controlling plasma, the hot, charged state of matter composed of electrons and atomic nuclei, or ions, that fuels fusion reactions. Theorists create computer models that simulate the processes involved, which experiments then test in attempts to confirm.

    Recent experiments at PPPL validated a code of Belova’s to predict a way to suppress a type of plasma instability that can halt fusion production. The method could prove useful to ITER, the international fusion facility under construction in France to demonstrate the ability to produce 10 times more power than it consumes.

    Second female physicist in Theory Department

    Belova, 53, joined PPPL in 1997 as the second female physicist to work in the Theory Department. Among her honors has been the Katherine E. Weimer Award for Women in Plasma Physics, a national honor named for the first woman theorist at PPPL, which Belova received in 2005.

    As a high school student in the former Soviet Union, Belova grew interested in mathematics and spent three years in an after-school program sponsored by the Moscow Institute of Physics and Technology. “In math you don’t really need to know anything,” she said. “You just solve puzzles. At least, this is what I thought in high school.”

    She earned a bachelor’s degree in applied mathematics in 1984 and a master’s degree in plasma physics in 1987, both from the Institute, though relatives had tried to persuade her not to switch subjects. “They said physics was too hard for a woman,” she recalled.

    But math had become too abstract for Belova and physics, while more difficult, was also more practical and exciting. She worked as a research engineer at the Space Research Institute in Moscow from 1987 to 1989 and as a junior research scientist from 1989 to 1992. While space physics is no longer her subject, her knowledge has served in good stead. “There are many common approaches in fusion and space plasma physics,” she said.

    Arrived in U.S. in 1992

    Belova and her husband, also a physicist, left Russia for the United States in 1992. She had been accepted in the graduate program at Dartmouth College, and became a research assistant in the Department of Physics and Astronomy. While she had learned technical English terms as an undergraduate student in Russia, her command of the broader language was still a bit shaky. “In my first year as a teaching assistant I would sometimes just write equations on the board and would point them out to students rather than trying to explain,” she said.

    After earning her doctorate in physics from Dartmouth in 1997 she worked as an associate research physicist at PPPL until 2004, a research physicist until 2008 and a principal research physicist since then. Among the scientific articles she has written at the Lab have been 15 invited papers for workshops and conferences around the world.

    Belova is the fourth PPPL staff member to be appointed to an editorial position in recent years. Richard Hawryluk, interim director of the laboratory, chairs the editorial board of the journal Nuclear Fusion; David Gates, principal research physicist and Stellarator Physics Division Head at PPPL, is editor-in-chief of the new online journal Plasma; and Igor Kaganovich, principal research physicist and deputy head of the PPPL Theory Department, serves as associate editor of Physics of Plasmas.

    See the full article here .

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    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. 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. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. 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.

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  • richardmitnick 7:55 am on November 28, 2017 Permalink | Reply
    Tags: , , , , Max-Planck-Princeton partnership in fusion research confirmed, Plasmas in astrophysics are being investigated at Max Planck Institute for Solar System Research in Göttingen and of Astrophysics in Garching and at the Faculty of Astrophysics of Princeton Universit, PPPL   

    From Max Planck Gesellschaft: “Max-Planck-Princeton partnership in fusion research confirmed” 

    Max Planck Gesellschaft

    November 28, 2017

    Isabella Milch
    Press Officer, Head of Public Relations and Press Department
    Max Planck Institute for Plasma Physics, Garching
    +49 89 3299-1288
    isabella.milch@ipp.mpg.de

    Investigation of plasmas in astrophysics and fusion research / funding for another two to five years.

    The scientific performance of Max-Planck-Princeton Center for Plasma Physics, established in 2012 by the Max Planck Society and Princeton University, USA, has been evaluated and awarded top grade. The Max Planck Society has now decided to continue its support for another two to maximum five years with 250,000 euros annually. The center’s objective is to link up the hitherto less coordinated research on fusion, laboratory and space plasmas and utilise synergies.

    1
    Turbulence in solar wind plasma. The simulation shows the magnetic field fluctuations due to turbulence. Their spatial and temporal structures can be compared with space probe measurements
    © MPI for Plasma Physics / Daniel Told

    The center’s partners in fusion research are Max Planck Institute for Plasma Physics (IPP) at Garching and Greifswald and Princeton Plasma Physics Laboratory (PPPL) in the USA. Plasmas in astrophysics are being investigated at Max Planck Institute for Solar System Research in Göttingen and of Astrophysics in Garching and at the Faculty of Astrophysics of Princeton University. Primarily through exchange of scientists, particularly junior scientists, computer codes have been jointly developed in the past five years and experimentation has been pursued on the devices MRX at Princeton, Vineta at Greifswald and ASDEX Upgrade at Garching. “For the evaluation the center presented a total of 150 publications, accounting for significant progress in central areas of plasma physics and astrophysics”, states Professor Per Helander, head of IPP’s Stellarator Theory division and, alongside Professor Amitava Bhattacharjee from PPPL, Deputy Director of Max-Planck-Princeton Center since 2017.

    For example, the old question in astrophysics why solar wind is much hotter than the sun’s surface can now be treated with a computer code developed to describe turbulence in fusion plasmas. This enabled plasma theoreticians from IPP along with US colleagues to investigate in detail the heating mechanism in solar wind plasma – with hitherto unattained accuracy – and compare their results with space probe measurements.

    Another puzzle whose solution has been approached at Max-Planck-Princeton Center: Why is it that in outer space and in the laboratory magnetic reconnection, i.e. rupture and relinking of magnetic field lines, is much faster than theory predicts? Whether solar corona or fusion plasma, the rearrangement of the field lines is always accompanied by fast conversion of magnetic energy to thermal and kinetic energy of plasma particles. Physicists from Max Planck Institute for Solar System Research and from the University of Princeton have described a fast mechanism that could describe the observations in the solar corona: formation of unstable plasmoids. Also the sawtooth instability in fusion plasmas, i.e. continual ejection of particles from the plasma core, derives from instantaneous reconnection of magnetic field lines. In the framework of the Max-Planck-Princeton cooperation IPP scientists have now come up with the first realistic simulation that can explain the superfast velocity.

    Last but not least, a new theory ansatz for calculating magnetic equilibria, first developed at Princeton, led to a very fast computer code. With the new algorithm, equilibrium calculations for the complex magnetic fields of future stellarator fusion devices no longer take months, but just a few minutes.

    “As hoped, the center has created new cooperations and built sturdy bridges, on the one hand between research on plasmas in fusion devices, in the laboratory and in outer space, and on the other hand between US and German plasma physicists”, as IPP’s Scientific Director Professor Sibylle Günter sums up the past five years of Max-Planck-Princeton Center. Along with Professor Stewart Prager of PPPL she is one of the two Co-directors of the center. The successful cooperation has meanwhile attracted further partners. In July 2017, a Memorandum of Understanding for admission of Japan’s National Institutes of Natural Sciences was signed: “We look forward to the next years of joint research”, states Sibylle Günter, “made possible by the present confirmation by the Max Planck Society”.

    Max Planck Princeton Research Center for Plasma Physics

    2
    Welcome to the Max-Planck-Princeton Center for Fusion and Astro Plasma Physics

    The center fosters collaboration between scientific institutes in both Germany and the USA. By leveraging the skills and expertise of scientists and engineers in both countries, and by promoting collaboration between astrophysicists and fusion scientists generally, the center hopes to accelerate discovery in fundamental areas of plasma physics.

    An equally important mission of the center is to support education and outreach to train the next generation of scientists. In the USA, this includes hosting training workshops for K-12 science teachers, and sponsoring summer research experiences for undergraduates.

    In Germany, the host institutions are the Max-Planck-Institut für Plasmaphysik (IPP), the Max-Planck-Institut for Solar System Research (MPS), and the Max Planck Institute for Astrophysics (MPA). In the USA, the host institutions are the Princeton Plasma Physics Laboratory (PPPL), and the Department of Astrophysical Sciences at Princeton University.

    To find out more about the Center, follow the links here.

    Funding for the Center is generously provided by the DoE Office of Science, the National Science Foundation, the Max-Planck Society, NASA’s Heliophysics Division, and Princeton University.

    See the full article here .

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    The Max Planck Society is Germany’s most successful research organization. Since its establishment in 1948, no fewer than 18 Nobel laureates have emerged from the ranks of its scientists, putting it on a par with the best and most prestigious research institutions worldwide. The more than 15,000 publications each year in internationally renowned scientific journals are proof of the outstanding research work conducted at Max Planck Institutes – and many of those articles are among the most-cited publications in the relevant field.

    What is the basis of this success? The scientific attractiveness of the Max Planck Society is based on its understanding of research: Max Planck Institutes are built up solely around the world’s leading researchers. They themselves define their research subjects and are given the best working conditions, as well as free reign in selecting their staff. This is the core of the Harnack principle, which dates back to Adolph von Harnack, the first president of the Kaiser Wilhelm Society, which was established in 1911. This principle has been successfully applied for nearly one hundred years. The Max Planck Society continues the tradition of its predecessor institution with this structural principle of the person-centered research organization.

    The currently 83 Max Planck Institutes and facilities conduct basic research in the service of the general public in the natural sciences, life sciences, social sciences, and the humanities. Max Planck Institutes focus on research fields that are particularly innovative, or that are especially demanding in terms of funding or time requirements. And their research spectrum is continually evolving: new institutes are established to find answers to seminal, forward-looking scientific questions, while others are closed when, for example, their research field has been widely established at universities. This continuous renewal preserves the scope the Max Planck Society needs to react quickly to pioneering scientific developments.

     
  • richardmitnick 5:34 pm on November 21, 2017 Permalink | Reply
    Tags: A high-resolution X-ray spectrometer for the largest and most powerful laser facility in the world, , PPPL   

    From PPPL: “PPPL scientists deliver new high-resolution diagnostic to national laser facility” 


    PPPL

    November 21, 2017
    Raphael Rosen

    1
    PPPL physicist Lan Gao performing the final check for crystal positioning and alignment before the instrument was shipped to NIF.

    2
    The three spectrometer channels inside the instrument. (Photo by Elle Starkman)

    4
    A cross section of the instrument showing three crystal spectrometers. (Photo by Elle Starkman)

    Scientists from the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have built and delivered a high-resolution X-ray spectrometer for the largest and most powerful laser facility in the world.


    LLNL/NIF

    The diagnostic, installed on the National Ignition Facility (NIF) at the DOE’s Lawrence Livermore National Laboratory, will analyze and record data from high-energy density experiments created by firing NIF’s 192 lasers at tiny pellets of fuel. Such experiments are relevant to projects that include the U.S. Stockpile Stewardship Program, which maintains the U.S. nuclear deterrent without full-scale testing, and to inertial confinement fusion, an alternative to the magnetic confinement fusion that PPPL studies.

    PPPL has used spectrometers for decades to analyze the electromagnetic spectrum of plasma, the hot fourth state of matter in which electrons have separated from atomic nuclei, inside doughnut-shaped fusion devices known as tokamaks. These devices heat the particles and confine them in magnetic fields, causing the nuclei to fuse and produce fusion energy. By contrast, NIF’s high-powered lasers cause fusion by heating the exterior of the fuel pellet. As the exterior vaporizes, pressure extends inward towards the pellet’s core, crushing hydrogen atoms together until they fuse and release their energy.

    NIF tested and confirmed that the spectrometer was operating as expected on September 28. During the experiment, the device accurately measured the electron temperature and density of a fuel capsule during the fusion process. “Measuring these conditions is key to achieving ignition of a self-sustaining fusion process on NIF,” said PPPL physicist Lan Gao, who helped design and build the device. “Everything worked out very nicely. The signal level we got was just like what we predicted.”

    The spectrometer will focus on a small capsule of simulated fuel that includes the element krypton to measure how the density and temperature of the hot electrons in the plasma change over time. “The fusion yield is very sensitive to temperature,” said Marilyn Schneider, leader of NIF’s Radiation Physics and Spectroscopic Diagnostics Group. “The spectrometer will provide the most sensitive temperature measurements to date. The device’s ability to plot temperature against time will also be very helpful.”

    Other PPPL researchers who contributed to this project include Principal Research Physicist Ken Hill; the Head of the Plasma Science & Technology Department Phil Efthimion; and graduate student Brian Kraus.

    See the full article here .

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    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. 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. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. 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.

     
  • richardmitnick 8:33 pm on November 13, 2017 Permalink | Reply
    Tags: , Findings could help scientists understand cosmic rays solar flares and solar eruptions — emissions from the sun that can disrupt cell phone service and knock out power grids on Earth, , , , PPPL,   

    From PPPL: “Plasma from lasers can shed light on cosmic rays, solar eruptions” 


    PPPL

    November 10, 2017
    Raphael Rosen

    1
    PPPL physicist Will Fox. (Photo by Elle Starkman)

    Lasers that generate plasma can provide insight into bursts of subatomic particles that occur in deep space, scientists have found. Such findings could help scientists understand cosmic rays, solar flares and solar eruptions — emissions from the sun that can disrupt cell phone service and knock out power grids on Earth.

    Physicists have long observed that particles like electrons and atomic nuclei can accelerate to extremely high speeds in space. Researchers believe that processes associated with plasma, the hot fourth state of matter in which electrons have separated from atomic nuclei, might be responsible. Some models theorize that magnetic reconnection, which takes place when the magnetic field lines in plasma snap apart and reconnect, releasing large amounts of energy, might cause the acceleration.

    Addressing this issue, a team of researchers led by Will Fox, physicist at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), recently used lasers to create conditions that mimic astrophysical behavior. The laboratory technique enables the study of outer-space-like plasma in a controlled and reproducible environment. “We want to reproduce the process in miniature to conduct these tests,” said Fox, lead author of the research published in the journal Physics of Plasmas.

    The team used a simulation program called Plasma Simulation Code (PSC) that tracks plasma particles in a virtual environment, where they are acted on by simulated magnetic and electric fields. The code originated in Germany and was further developed by Fox and colleagues at the University of New Hampshire before he joined PPPL. Researchers conducted the simulations on the Titan supercomputer at the Oak Ridge Leadership Computing Facility, a DOE Office of Science User Facility, at Oak Ridge National Laboratory, through the DOE’s Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program.

    ORNL Cray Titan XK7 Supercomputer

    The simulations build on research by Fox and other scientists establishing that laser-created plasmas can facilitate the study of acceleration processes. In the new simulations, such plasmas bubble outward and crash into each other, triggering magnetic reconnection. These simulations also suggest two kinds of processes that transfer energy from the reconnection event to particles.

    During one process, known as Fermi acceleration, particles gain energy as they bounce back and forth between the outer edges of two converging plasma bubbles. In another process called X-line acceleration, the energy transfers to particles as they interact with the electric fields that arise during reconnection.

    Fox and the team now plan to conduct physical experiments that replicate conditions in the simulations using both the OMEGA laser facility at the University of Rochester’s Laboratory for Laser Energetics and the National Ignition Facility at the DOE’s Lawrence Livermore National Laboratory. “We’re trying to see if we can get particle acceleration and observe the energized particles experimentally,” Fox said.

    Collaborating with Fox on the research reported in Physics of Plasmas were physicists at PPPL, Princeton University, and the University of Michigan. Funding came from the DOE’s Office of Science (Fusion Energy Sciences and the National Nuclear Security Administration).

    See the full article here .

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    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. 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. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. 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.

     
  • richardmitnick 7:42 am on October 17, 2017 Permalink | Reply
    Tags: , , , , PPPL, SSEN-steady-state electrical network   

    From PPPL: “PPPL completes shipment of electrical components to power site for ITER, the international fusion experiment” 


    PPPL

    October 16, 2017
    Jeanne Jackson DeVoe

    1
    Electrical components procured by PPPL. Pictured clockwise: switchgear, HV protection and control cubicles, resistors, and insulators. (Photo by Photo courtesy of © ITER Organization, http://www.iter.org/)

    The arrival of six truckloads of electrical supplies at a warehouse for the international ITER fusion experiment on Oct. 2 brings to a successful conclusion a massive project that will provide 120 megawatts of power – enough to light up a small city − to the 445-acre ITER site in France.

    ITER Tokamak in Saint-Paul-lès-Durance, which is in southern France

    The Princeton Plasma Physics Laboratory (PPPL), with assistance from the Department of Energy’s Princeton Site Office, headed the $34 million, five-year project on behalf of US ITER to provide three quarters of the components for the steady-state electrical network (SSEN), which provides electricity for the lights, pumps, computers, heating, ventilation and air conditioning to the huge fusion energy experiment. ITER connected the first transformer to France’s electrical grid in March. The European Union is providing the other 25 percent.

    The shipment was the 35th and final delivery of equipment from companies all over the world, including from the United States over the past three years.

    “I think it’s a great accomplishment to finish this,” said Hutch Neilson, head of ITER Fabrication. “The successful completion of the SSEN program is a very important accomplishment both for the US ITER project and for PPPL as a partner in the US ITER project.”

    The six trucks that arrived carried a total of 63 crates of uninterruptible power supply equipment weighing 107 metric tons. The trucks took a seven-hour, 452-mile journey from Gutor UPS and Power Conversion in Wettingen, Switzerland, northwest of Zurich, to an ITER storage facility in Port-Saint-Louis-Du-Rhône, France. The equipment will eventually be used to provide emergency power to critical ITER systems in the event of a power outage.

    “This represents the culmination of a very complex series of technical specifications and global purchases, and we are grateful to the entire PPPL team and their vendors for outstanding commitment and performance”, said Ned Sauthoff, director of the US ITER Project Office at Oak Ridge National Laboratory, where all U.S. contributions to ITER are managed for the U.S. Department of Energy’s Office of Science.

    A device known as a tokamak, ITER will be the largest and most powerful fusion machine in the world. Designed to produce 500 megawatts of fusion power for 50 megawatts of input power, it will be the first fusion device to create net energy – it will get more energy out than is put in. Fusion is the process by which stars like the sun create energy – the fusing of light elements

    A separate electrical system for the pulsed power electrical network (PPEN), procured by China, will power the ITER tokamak.

    The first SSEN delivery in 2014 was among the first plant components to be delivered to the ITER site. The SSEN project is now one of the first U.S. packages to be completed in its entirety, Neilson said. He noted that the final shipment arrived 10 days ahead of PPPL’s deadline.

    In addition to the electrical components, PPPL is also responsible for seven diagnostic instruments and for integrating the instruments inside ITER port plugs. While PPPL is continuing work on an antenna for one diagnostic, most of the diagnostic and port integration work has been put on hold amid uncertainty over U.S. funding for its contributions to ITER.

    The SSEN project was a complex enterprise. PPPL researched potential suppliers, solicited and accepted bids, and oversaw the production and testing of electrical components in 16 separate packages worth a total of about $30 million. The effort involved PPPL engineers, as well as procurement and quality assurance staff members who worked to make sure that the components met ITER specifications and would do exactly what they are supposed to do. “It’s really important that we deliver to ITER equipment that exactly meets the requirements they specify and that it be quality equipment that doesn’t give them trouble down the road,” Neilson said. “So every member of the team makes sure that gets done.”

    Many of the components were for the high-voltage switchyard. A massive transformer procured by PPPL was connected to the French electrical grid in March. PPPL procured and managed the purchase and transportation of the 87-ton transformer and three others, which were built in South Korea by Hyundai Heavy Industries, a branch of the company known for producing cars. =

    The SSEN components came from as close to home as Mount Pleasant, Pennsylvania, to as far away as Turkey, with other components coming from Mexico, Italy, Spain, France, Germany, South Korea and the Netherlands.

    John Dellas, the head of electrical systems and the team leader for the project, has been working on the ITER SSEN project for the entire five years of the program. He traveled to Schweinfurt, Germany, to oversee testing of the control and protection systems for the high-voltage switchyard.

    Dellas took over the project from Charles Neumeyer after Neumeyer became engineering director for the NSTX-U Recovery Project last year. Dellas said Neumeyer deserves most of the credit for the program. “Charlie took the team down to the 10-yard line and I put everything in the end zone,” Dellas said. “I was working with Charlie but Charlie was the quarterback.”

    Neumeyer worked on the project from 2006, when the project was in the planning stages, until 2016. He said he was happy to see the project completed. “It’s very gratifying to see roughly 10 years of work come to a satisfying conclusion under budget and on schedule,” he said.

    See the full article here .

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    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. 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. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. 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.

     
  • richardmitnick 8:51 pm on October 13, 2017 Permalink | Reply
    Tags: 2-D structure of turbulence in tokamaks, , , , PPPL   

    From PPPL: “PPPL takes detailed look at 2-D structure of turbulence in tokamaks” 


    PPPL

    October 13, 2017
    John Greenwald

    1
    Correlation analysis of three plasma discharges on NSTX for each of five different radial locations near the plasma edge. The red regions marked with a blue cross have high positive correlation around the origin point, while the blue regions marked with a yellow cross have high negative correlation. Images courtesy of Stewart Zweben.

    A key hurdle for fusion researchers is understanding turbulence, the ripples and eddies that can cause the superhot plasma that fuels fusion reactions to leak heat and particles and keep fusion from taking place. Comprehending and reducing turbulence will facilitate the development of fusion as a safe, clean and abundant source of energy for generating electricity from power plants around the world.

    At the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), scientists have assembled a large database of detailed measurements of the two dimensional (2-D) structure of edge plasma turbulence made visible by a diagnostic technique known as gas puff imaging. The two dimensions, measured inside a fusion device called a tokamak, represent the radial and vertical structure of the turbulence.

    Step toward fuller understanding

    “This study is an incremental step toward a fuller understanding of turbulence,” said physicist Stewart Zweben, lead author of the research published in the journal Physics of Plasmas. “It could help us understand how turbulence functions as the main cause of leakage of plasma confinement.”

    Fusion occurs naturally in space, merging the light elements in plasma to release the energy that powers the sun and stars. On Earth, researchers create fusion in facilities like tokamaks, which control the hot plasma with magnetic fields. But turbulence frequently causes heat to leak from its magnetic confinement.

    PPPL scientists have now delved beyond previously published characterizations of turbulence and analyzed the data to focus on the 2-D spatial correlations within the turbulence. This correlation provides clues to the origin of the turbulent behavior that causes heat and particle leakage, and will serve as an additional basis for testing computer simulations of turbulence against empirical evidence.

    Studying 20 discharges of plasma

    The paper studied 20 discharges of plasma chosen as a representative sample of those created in PPPL’s National Spherical Torus Experiment (NSTX) prior to its recent upgrade. In each of these discharges, a gas puff illuminated the turbulence near the edge of the plasma, where turbulence is of special interest. The puffs, a source of neutral atoms that glow in response to density changes within a well-defined region, allowed researchers to see fluctuations in the density of the turbulence. A fast camera recorded the resulting light at the rate of 400,000 frames per second over an image frame size of 64 pixels wide by 80 pixels high.

    Zweben and co-authors performed computational analysis of the data from the camera, determining the correlations between different regions of the frames as the turbulent eddies moved through them. “We’re observing the patterns of the spatial structure,” Zweben said. “You can compare it to the structure of clouds drifting by. Some large clouds can be massed together or there can be a break with just plain sky.”

    Detailed view of turbulence

    The correlations provide a detailed view of the nature of plasma turbulence. “Simple things about turbulence like its size and time scale have long been known,” said PPPL physicist Daren Stotler, a coauthor of the paper. “These simulations take a deep dive into another level to look at how turbulence in one part of the plasma varies with respect to turbulence in another part.”

    In the resulting graphics, a blue cross indicates the point of focus for a calculation; the red and yellow areas around the cross are regions in which the turbulence is evolving similarly to the turbulence at the focal point. Farther away, researchers found regions in which the turbulence is changing opposite to the changes at the focal point. These farther-away regions are shown as shades of blue in the graphics, with the yellow cross indicating the point with the most negative correlation.

    For example, if the red and yellow images were a region of high density turbulence, the blue images indicated low density. “The density increase must come from somewhere,” said Zweben. “Maybe from the blue regions.”

    Going forward, knowledge of these correlations could be used to predict the behavior of turbulence in magnetically confined plasma. Success of the effort could deepen understanding of a fundamental cause of the loss of heat from fusion reactions.

    Also contributing to this study were Filippo Scotti of the Lawrence Livermore National Laboratory and J. R. Myra of Lodestar Research Corporation. Support for this work comes from the DOE Office of Science.

    See the full article here .

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    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. 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. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. 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.

     
  • richardmitnick 2:40 pm on September 14, 2017 Permalink | Reply
    Tags: Alfvén eigenmodes, , DIII-D National Fusion Facility, , NOVA and ORBIT simulation codes, , PPPL   

    From PPPL: “Physicists propose new way to stabilize next-generation fusion plasmas” 


    PPPL

    September 11, 2017
    Raphael Rosen

    1
    PPPL physicist Gerrit Kramer.(Photo by Elle Starkman)

    A key issue for next-generation fusion reactors is the possible impact of many unstable Alfvén eigenmodes, wave-like disturbances produced by the fusion reactions that ripple through the plasma in doughnut-shaped fusion facilities called “tokamaks.” Deuterium and tritium fuel react when heated to temperatures near 100 million degrees Celsius, producing high-energy helium ions called alpha particles that heat the plasma and sustain the fusion reactions.

    These alpha particles are even hotter than the fuel and have so much energy that they can drive Alfvén eigenmodes that allow the particles to escape from the reaction chamber before they can heat the plasma. Understanding these waves and how they help alpha particles escape is a key research topic in fusion science.

    If only one or two of these waves are excited in the reaction chamber, the effect on the alpha particles and their ability to heat the fuel is limited. However, theorists have predicted for some time that if many of these waves are excited, they can collectively throw out a lot of alpha particles, endangering the reactor chamber walls and the efficient heating of the fuel.

    Recent experiments conducted on the DIII-D National Fusion Facility, which General Atomics operates for the U.S. Department of Energy (DOE) in San Diego, have revealed evidence that confirms these theoretical predictions.

    1
    DIII-D National Fusion Facility

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    https://lasttechage.wordpress.com/2011/07/11/fusion-seawater-and-stewart-pragers-oped/

    Losses of up to 40 percent of high-energy particles are observed in experiments when many Alfvén waves are excited by deuterium beam ions used to simulate alpha particles and higher-energy beam ions in a fusion reactor such as ITER, which is now under construction in the south of France.

    In the wake of this research, physicists at the DOE’s Princeton Plasma Physics Laboratory (PPPL) produced a quantitatively accurate model of the impact of these Alfvén waves on high-energy deuterium beams in the DIII-D tokamak. They used simulation codes called NOVA and ORBIT to predict which Alfvén waves would be excited and their effect on the confinement of the high-energy particles.

    The researchers confirmed the NOVA modeling prediction that over 10 unstable Alfvén waves can be excited by the deuterium beams in the DIII-D experiment. Furthermore, in quantitative agreement with the experimental results, the modeling predicted that up to 40 percent of the energetic particles would be lost. The modeling demonstrated for the first time, in this type of high-performance plasma, that quantitatively accurate predictions can be made for the effect of multiple Alfvén waves on the confinement of energetic particles in the DIII-D tokamak.

    “Our team confirmed that we can quantitatively predict the conditions where the fusion alpha particles can be lost from the plasma based on the results obtained from the modeling of the DIII-D experiments” said Gerrit Kramer, a PPPL research physicist and lead author of a paper that describes the modeling results in the May issue of the journal Nuclear Fusion.

    The joint findings marked a potentially large advance in comprehension of the process. “These results show that we now have a strong understanding of the individual waves excited by the energetic particles and how these waves work together to expel energetic particles from the plasma,” said physicist Raffi Nazikian, head of the ITER and Tokamaks Department at PPPL and leader of the laboratory’s collaboration with DIII-D.

    The NOVA+ORBIT model further indicated that certain plasma conditions could dramatically reduce the number of Alfvén waves and hence lower the energetic-particle losses. Such waves and the losses they produce could be minimized if the electric current profile in the center of the plasma could be broadened, according to the analysis presented in the scientific article.

    Experiments to test these ideas for reducing energetic particle losses will be conducted in a following research campaign on DIII-D. “New upgrades to the DIII-D facility will allow for the exploration of improved plasma conditions,” Nazikian said. “New experiments are proposed to access conditions predicted by the theory to reduce energetic particle losses, with important implications for the optimal design of future reactors.”

    The DOE Office of Science supported this research. Members of the research team contributing to the published article included scientists from PPPL, General Atomics, Lawrence Livermore National Laboratory and the University of California, Irvine.

    See the full article here .

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    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. 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. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. 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.

     
  • richardmitnick 3:21 pm on September 8, 2017 Permalink | Reply
    Tags: , Breaking apart and snapping together of the magnetic field lines in plasma that occurs throughout the universe, Could lead to improved forecasts of space weather, , , PPPL, Team led by graduate student at PPPL produces unique simulation of magnetic reconnection   

    From PPPL: “Team led by graduate student at PPPL produces unique simulation of magnetic reconnection” 


    PPPL

    September 8, 2017
    John Greenwald

    1
    Northern lights in the night sky over Norway. (Photo by Jan R. Olsen)

    Jonathan Ng, a Princeton University graduate student at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), has for the first time applied a fluid simulation to the space plasma process behind solar flares northern lights and space storms. The model could lead to improved forecasts of space weather that can shut down cell phone service and damage power grids, as well as to better understanding of the hot, charged plasma gas that fuels fusion reactions.

    The new simulation captures the physics of magnetic reconnection, the breaking apart and snapping together of the magnetic field lines in plasma that occurs throughout the universe. The simulations approximate kinetic effects in a fluid code, which treats plasma as a flowing liquid, to create a more detailed picture of the reconnection process.

    Previous simulations used fluid codes to produce simplified descriptions of reconnection that takes place in the vastness of space, where widely separated plasma particles rarely collide. However, this collisionless environment gives rise to kinetic effects on plasma behavior that fluid models cannot normally capture.

    Estimation of kinetic behavior

    The new simulation estimates kinetic behavior. “This is the first application of this particular fluid model in studying reconnection physics in space plasmas,” said Ng, lead author of the findings reported in August in the journal Physics of Plasmas.

    Ng and coauthors approximated kinetic effects with a series of fluid equations based on plasma density, momentum and pressure. They concluded the process through a mathematical technique called “closure” that enabled them to describe the kinetic mixing of particles from non-local, or large-scale, regions. The type of closure involved was originally developed by PPPL physicist Greg Hammett and the late Rip Perkins in the context of fusion plasmas, making its application to the space plasma environment an example of fruitful cross-fertilization.

    The completed results agreed better with kinetic models as compared with simulations produced by traditional fluid codes. The new simulations could extend understanding of reconnection to whole regions of space such as the magnetosphere, the magnetic field that surrounds the Earth, and provide a more comprehensive view of the universal process.

    Magnetosphere of Earth, original bitmap from NASA. SVG rendering by Aaron Kaase

    Coauthoring the paper were physicists Ammar Hakim of PPPL and Amitava Bhattacharjee, head of the Theory Department at PPPL and a professor of astrophysical sciences at Princeton University, together with physicists Adam Stanier and William Daughton of Los Alamos National Laboratory. Support for this work comes from the DOE Office of Science, the National Science Foundation and NASA. Computation was performed at the National Energy Research Scientific Computer Center, a DOE Office of Science User Facility, and the University of New Hampshire.

    See the full article here .

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    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. 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. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. 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.

     
  • richardmitnick 1:31 pm on August 28, 2017 Permalink | Reply
    Tags: , , , PPPL,   

    From PPPL: “PPPL physicists essential to new campaign on world’s most powerful stellarator” 


    PPPL

    August 28, 2017
    John Greenwald

    KIT Wendelstein 7-X, built in Greifswald, Germany

    1
    Fish-eye view of interior of W7-X showing graphite tiles that cover magnetic coils. (Photo courtesy of IPP.)

    Physicists from the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) are providing critical expertise for the first full campaign of the world’s largest and most powerful stellarator, a magnetic confinement fusion experiment, the Wendelstein 7-X (W7-X) in Germany. The fusion facility resumes operating on August 28, 2017, and will investigate the suitability of its optimized magnetic fields to create steady state plasmas and to serve as a model for a future power plant for the production of a “star in a jar,” a virtually limitless source of safe and clean energy for generating electricity.

    The W7-X started up in December, 2015, and concluded its initial run in March, 2016. The facility has since been upgraded to prepare for the high-power campaign that is set to begin.

    Deeply involved in the new 15-week run are PPPL physicists Sam Lazerson and Novimir Pablant, who are spending two years at the Max Planck Institute of Plasma Physics in Greifswald, Germany. Lazerson, who previously mapped the W7-X magnetic fields with barn-door sized magnetic coils built by PPPL, heads a task force that will plan and run a series of experiments on the stellarator. Pablant, who designed an x-ray crystal spectrometer to record the behavior of W7-X plasma, will operate the diagnostic together with a German spectrometer and will contribute to planning and executing research.

    First run in designed configuration

    “This will be the first run of the machine in its designed configuration,” said David Gates, who heads the stellarator physics division at PPPL and oversees the laboratory’s role as lead U.S. collaborator in the W7-X project. The new run will test a device called an “island divertor” for exhausting thermal energy and impurities. The campaign will also increase the heating power of the stellarator to eight megawatts to enable operation at a higher beta — the ratio of plasma pressure to the magnetic field pressure, a key factor for plasma confinement.

    Such progress marks steps toward lengthening the confinement time of the hot, charged plasma gas that fuels fusion reactions within the optimized machine. “The goal is to increase plasma confinement compared with traditional stellarators,” said Gates.

    Going forward, Max Planck engineers plan to install a U.S.-built “scraper element” on the W7-X after completion of the initial 15-week campaign. The following phase will study the ability of the unit, originally designed at Oak Ridge National Laboratory and completed at PPPL, to intercept heat flowing toward the divertor and improve its performance. Plans call next for installation of a water-cooled divertor in 2019 to further increase the allowable pulse length of the stellarator.

    See the full article here .

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    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. 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. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. 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.

     
  • richardmitnick 8:36 pm on July 14, 2017 Permalink | Reply
    Tags: A high Mach number shock wave, High-energy plasma, , , PPPL, The first high-energy shock waves in a laboratory setting, U Rochester OMEGA EP Laser System   

    From PPPL: “Scientists create first laboratory generation of high-energy shock waves that accelerate astrophysical particles” 


    PPPL

    July 14, 2017
    John Greenwald

    1
    Physicist Derek Schaeffer. (Photo by Elle Starkman/Office of Communications).

    Throughout the universe, supersonic shock waves propel cosmic rays and supernova particles to velocities near the speed of light. The most high-energy of these astrophysical shocks occur too far outside the solar system to be studied in detail and have long puzzled astrophysicists. Shocks closer to Earth can be detected by spacecraft, but they fly by too quickly to probe a wave’s formation.

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    No image credit or caption.

    Opening the door to new understanding

    Now a team of scientists has generated the first high-energy shock waves in a laboratory setting, opening the door to new understanding of these mysterious processes. “We have for the first time developed a platform for studying highly energetic shocks with greater flexibility and control than is possible with spacecraft,” said Derek Schaeffer, a physicist at Princeton University and the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), and lead author of a July paper in Physical Review Letters that outlines the experiments.

    Schaeffer and colleagues conducted their research on the Omega EP laser facility at the University of Rochester Laboratory for Laser Energetics.

    3
    U Rochester OMEGA EP Laser System

    U Rochester Omega Laser

    Collaborating on the project was PPPL physicist Will Fox, who designed the experiment, and researchers from Rochester and the universities of Michigan and New Hampshire. “This lets you understand the evolution of the physical processes going on inside shock waves,” Fox said of the platform.

    To produce the wave, scientists used a laser to create a high-energy plasma — a form of matter composed of atoms and charged atomic particles — that expanded into a pre-existing magnetized plasma. The interaction created, within a few billionths of a second, a magnetized shock wave that expanded at a rate of more than 1 million miles per hour, congruent with shocks beyond the solar system. The rapid velocity represented a high “magnetosonic Mach number” and the wave was “collisionless,” emulating shocks that occur in outer space where particles are too far apart to frequently collide.

    Discovery by accident

    Discovery of this method of generating shock waves actually came about by accident. The physicists had been studying magnetic reconnection, the process in which the magnetic field lines in plasma converge, separate and energetically reconnect. To investigate the flow of plasma in the experiment, researchers installed a new diagnostic on the Rochester laser facility. To their surprise, the diagnostic revealed a sharp steepening of the density of the plasma, which signaled the formation of a high Mach number shock wave.

    To simulate the findings, the researchers ran a computer code called “PSC” on the Titan supercomputer, the most powerful U.S. computer, housed at the DOE’s Oak Ridge Leadership Computing Facility.

    ORNL Cray XK7 Titan Supercomputer

    The simulation utilized data derived from the experiments and results of the model agreed well with diagnostic images of the shock formation.

    Going forward, the laboratory platform will enable new studies of the relationship between collisionless shocks and the acceleration of astrophysical particles. The platform “complements present remote sensing and spacecraft observations,” the authors wrote, and “opens the way for controlled laboratory investigations of high-Mach number shocks.”

    Support for this research came from the DOE Office of Science, the DOE INCITE Leadership Computing program, and the National Nuclear Security Administration, a semi-autonomous agency within the DOE.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition


    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. 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. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. 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.

     
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