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  • richardmitnick 3:05 pm on January 3, 2018 Permalink | Reply
    Tags: , , , , Magnetic reconnection, Magnetospheric Multiscale Mission, , or MMS   

    From Goddard: “NASA’s Magnetospheric Multiscale Mission Locates Elusive Electron Act” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Jan. 3, 2018
    Mara Johnson-Groh
    mara.johnson-groh@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    The space high above Earth may seem empty, but it’s a carnival packed with magnetic field lines and high-energy particles. This region is known as the magnetosphere and, every day, charged particles put on a show as they dart and dive through it.

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

    Like tiny tightrope walkers, the high-energy electrons follow the magnetic field lines. Sometimes, such as during an event called magnetic reconnection where the lines explosively collide, the particles are shot off their trajectories, as if they were fired from a cannon.

    Since these acts can’t be seen by the naked eye, NASA uses specially designed instruments to capture the show. The Magnetospheric Multiscale Mission, or MMS, is one such looking glass through which scientists can observe the invisible magnetic forces and pirouetting particles that can impact our technology on Earth. New research uses MMS data to improve understanding of how electrons move through this complex region — information that will help untangle how such particle acrobatics affect Earth.

    NASA/MMS

    NASA MMS satellites in space


    This visualization shows the motion of one electron in the magnetic reconnection region. As the spacecraft approaches the reconnection region, it detects first high-energy particles, then low-energy particles. Credits: NASA’s Goddard Space Flight Center/Tom Bridgman

    Scientists with MMS have been watching the complex shows electrons put on around Earth and have noticed that electrons at the edge of the magnetosphere often move in rocking motions as they are accelerated. Finding these regions where electrons are accelerated is key to understanding one of the mysteries of the magnetosphere: How does the magnetic energy seething through the area get converted to kinetic energy — that is, the energy of particle motion. Such information is important to protect technology on Earth, since particles that have been accelerated to high energies can at their worst cause power grid outages and GPS communications dropouts.

    New research, published in the Journal of Geophysical Research, found a novel way to help locate regions where electrons are accelerated. Until now, scientists looked at low-energy electrons to find these accelerations zones, but a group of scientists lead by Matthew Argall of the University of New Hampshire in Durham has shown it’s possible, and in fact easier, to identify these regions by watching high-energy electrons.

    This research is only possible with the unique design of MMS, which uses four spacecraft flying in a tight tetrahedral formation to give high temporal and spatial resolution measurements of the magnetic reconnection region.

    “We’re able to probe very small scales and this helps us to really pinpoint how energy is being converted through magnetic reconnection,” Argall said.

    The results will make it easier for scientists to identify and study these regions, helping them explore the microphysics of magnetic reconnection and better understand electrons’ effects on Earth.

    See the full article here.

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.


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  • richardmitnick 3:01 pm on December 4, 2017 Permalink | Reply
    Tags: Airapetian and Goddard colleague William Danchi argue the solar flares were an essential part of the process that led to us, As a way to potentially improve the chances of finding habitable conditions on those exoplanets that are observed a new approach has been proposed by a group of NASA scientists, , , , , , , Magnetic reconnection, , The novel technique takes advantage of the frequent stellar storms emanating from cool young dwarf stars, This new research suggests that some stellar storms could have just the opposite effect — making the planet more habitable., When high-energy particles from a stellar storm reach an exoplanet they break the nitrogen oxygen and water molecules that may be in the atmosphere into their individual components   

    From Many Worlds: “A New Way to Find Signals of Habitable Exoplanets?” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-12-04
    Marc Kaufman

    1
    Scientists propose a new and more indirect way of determining whether an exoplanet has a good, bad or unknowable chance of being habitable. (NASA’s Goddard Space Flight Center/Mary Pat Hrybyk)

    The search for biosignatures in the atmospheres of distant exoplanets is extremely difficult and time-consuming work. The telescopes that can potentially take the measurements required are few and more will come only slowly. And for the current and next generation of observatories, staring at a single exoplanet long enough to get a measurement of the compounds in its atmosphere will be a time-consuming and expensive process — and thus a relatively infrequent one.

    As a way to potentially improve the chances of finding habitable conditions on those exoplanets that are observed, a new approach has been proposed by a group of NASA scientists.

    The novel technique takes advantage of the frequent stellar storms emanating from cool, young dwarf stars. These storms throw huge clouds of stellar material and radiation into space – traveling near the speed of light — and the high energy particles then interact with exoplanet atmospheres and produce chemical biosignatures that can be detected.

    The study, titled “Atmospheric Beacons of Life from Exoplanets Around G and K Stars“, recently appeared in Nature Scientific Reports.

    “We’re in search of molecules formed from fundamental prerequisites to life — specifically molecular nitrogen, which is 78 percent of our atmosphere,” said Airapetian, who is a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and at American University in Washington, D.C. “These are basic molecules that are biologically friendly and have strong infrared emitting power, increasing our chance of detecting them.”

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    The thin gauzy rim of the planet in foreground is an illustration of its atmosphere. (NASA’s Goddard Space Flight Center)

    So this technique, called a search for “Beacons of Life,” would not detect signs of life per se, but would detect secondary or tertiary signals that would, in effect, tell observers to “look here.”

    The scientific logic is as follows:

    When high-energy particles from a stellar storm reach an exoplanet, they break the nitrogen, oxygen and water molecules that may be in the atmosphere into their individual components.

    Water molecules become hydroxyl — one atom each of oxygen and hydrogen, bound together. This sparks a cascade of chemical reactions that ultimately produce what the scientists call the atmospheric beacons of hydroxyl, more molecular oxygen, and nitric oxide.

    For researchers, these chemical reactions are very useful guides. When starlight strikes the atmosphere, spring-like bonds within the beacon molecules absorb the energy and vibrate, sending that energy back into space as heat, or infrared radiation. Scientists know which gases emit radiation at particular wavelengths of light. So by looking at all the radiation coming from the that planet’s atmosphere, it’s possible to get a sense of what chemicals are present and roughly in what amounts..

    Forming a detectable amount of these beacons requires a large quantity of molecular oxygen and nitrogen. As a result, if detected these compounds would suggest the planet has an atmosphere filled with biologically friendly chemistry as well as Earth-like atmospheric pressure. The odds of the planet being a habitable world remain small, but those odds do grow.

    “These conditions are not life, but are fundamental prerequisites for life and are comparable to our Earth’s atmosphere,” Airapetian wrote in an email.

    Stellar storms and related coronal mass ejections are thought to burst into space when magnetic reconnections in various regions of the star. For stars like our sun, the storms become less frequent within a relatively short period, astronomically speaking. Smaller and less luminous red dwarf stars, which are the most common in the universe, continue to send out intense stellar flares for a much longer time.

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    Vladimir Airapetian is a senior researcher at NASA Goddard and a member of NASA’s Nexus for Exoplanet System Science (NExSS) initiative.

    The effect of stellar weather on planets orbiting young stars, including our own four billion years ago, has been a focus of Airapetian’s work for some time.

    For instance, Airapetian and Goddard colleague William Danchi published a paper in the journal Nature last year proposing that solar flares warmed the early Earth to make it habitable. They concluded that the high-energy particles also provided the vast amounts of energy needed to combine evenly scattered simple molecules into the kind of complex molecules that could keep the planet warm and form some of the chemical building blocks of life.

    In other words, they argue, the solar flares were an essential part of the process that led to us.

    What Airapetian is proposing now is to look at the chemical results of stellar flares hitting exoplanet atmospheres to see if they might be an essential part of a life-producing process as well, or of a process that creates a potentially habitable planet.

    Airapetian said that he is again working with Danchi, a Goddard astrophysicist, and the team from heliophysics to propose a NASA mission that would use some of their solar and stellar flare findings. The mission being conceived, the Exo Life Beacon Space Telescope (ELBST), would measure infrared emissions of an exoplanet atmosphere using direct imaging observations, along with technology to block the infrared emissions of the host star.

    For this latest paper, Airapetian and colleagues used a computer simulation to study the interaction between the atmosphere and high-energy space weather around a cool, active star. They found that ozone drops to a minimum and that the decline reflects the production of atmospheric beacons.

    They then used a model to calculate just how much nitric oxide and hydroxyl would form and how much ozone would be destroyed in an Earth-like atmosphere around an active star. Earth scientists have used this model for decades to study how ozone — which forms naturally when sunlight strikes oxygenin the upper atmosphere — responds to solar storms. But the ozone reactions found a new application in this study; Earth is, after all, the best case study in the search for habitable planets and life.

    Will this new approach to searching for habitable planets out?

    “This is an exciting new proposed way to look for life,” said Shawn Domagal-Goldman, a Goddard astrobiologist not connected with the study. “But as with all signs of life, the exoplanet community needs to think hard about context. What are the ways non-biological processes could mimic this signature?”

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    A 2012 coronal mass ejection from the sun. Earth is placed into the image to give a sense of the size of the solar flare, but our planet is of course nowhere near the sun. (NASA, Goddard Media Studios)

    Today, Earth enjoys a layer of protection from the high-energy particles of solar storms due to its strong magnetic field. However, some particularly strong solar events can still interact with the magnetosphere and potentially wreak havoc on certain technology on Earth.

    The National Oceanic and Atmospheric Administration classifies solar storms on a scale of one to five (one being the weakest; five being the most severe). For instance, a storm forecast to be a G3 event means it could have the strength to cause fluctuations in some power grids, intermittent radio blackouts in higher latitudes and possible GPS issues.

    This is what can happen to a planet with a strong magnetic field and a sun that is no longer prone to sending out frequent solar flares. Imagine what stellar storms can do when the star is younger and more prone to powerful flaring, and the planet less protected.

    Exoplanet scientists often talk of the possibility that a particular planet was “sterilized” by the high-energy storms, and so could never be habitable. But this new research suggests that some stellar storms could have just the opposite effect — making the planet more habitable.

    See the full article here.

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    About Many Worlds

    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 2:21 pm on December 2, 2017 Permalink | Reply
    Tags: , , , , Magnetic reconnection, , , Plasmas, Study sheds light on turbulence in astrophysical plasmas, Turbulent state of solar wind   

    From MIT: “Study sheds light on turbulence in astrophysical plasmas” 

    MIT News

    MIT Widget

    MIT News

    December 1, 2017
    David L. Chandler

    1
    Magnetic reconnection is a complicated phenomenon that Nuno Loureiro, an associate professor of nuclear science and engineering and of physics at MIT, has been studying in detail for more than a decade. To explain the process, he gives a well-studied example: “If you watch a video of a solar flare” as it arches outward and then collapses back onto the sun’s surface, “that’s magnetic reconnection in action. It’s something that happens on the surface of the sun that leads to explosive releases of energy.” Loureiro’s understanding of this process of magnetic reconnection has provided the basis for the new analysis that can now explain some aspects of turbulence in plasmas. Image: NASA

    Theoretical analysis uncovers new mechanisms in plasma turbulence.

    Plasmas, gas-like collections of ions and electrons, make up an estimated 99 percent of the visible matter in the universe, including the sun, the stars, and the gaseous medium that permeates the space in between. Most of these plasmas, including the solar wind that constantly flows out from the sun and sweeps through the solar system, exist in a turbulent state. How this turbulence works remains a mystery; it’s one of the most dynamic research areas in plasma physics.

    Now, two researchers have proposed a new model to explain these dynamic turbulent processes.

    The findings, by Nuno Loureiro, an associate professor of nuclear science and engineering and of physics at MIT, and Stanislav Boldyrev, a professor of physics at the University of Wisconsin at Madison, are reported today in The Astrophysical Journal. The paper is the third in a series this year explaining key aspects of how these turbulent collections of charged particles behave.

    “Naturally occurring plasmas in space and astrophysical environments are threaded by magnetic fields and exist in a turbulent state,” Loureiro says. “That is, their structure is highly disordered at all scales: If you zoom in to look more and more closely at the wisps and eddies that make up these materials, you’ll see similar signs of disordered structure at every size level.” And while turbulence is a common and widely studied phenomenon that occurs in all kinds of fluids, the turbulence that happens in plasmas is more difficult to predict because of the added factors of electrical currents and magnetic fields.

    “Magnetized plasma turbulence is fascinatingly complex and remarkably challenging,” he says.

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    Simulation conducted by MIT student Daniel Groselj.

    Loureiro and Boldyrev found that magnetic reconnection must play a crucial role in the dynamics of plasma turbulence, an insight that they say fundamentally changes the understanding of the dynamics and properties of space and astrophysical plasmas and “is indeed a conceptual shift in how one thinks about turbulence,” Loureiro says.

    Existing hypotheses about the dynamics of plasma turbulence “can correctly predict some aspects of what is observed,” he says, but they “lead to inconsistencies.”

    Loureiro worked with Boldyrev, a leading theorist on plasma turbulence, and the two realized “we can fix this by essentially merging the existing theoretical descriptions of turbulence and magnetic reconnection,” Loureiro explains. As a result, “the picture of turbulence gets conceptually modified and leads to results that more closely match what has been observed by satellites that monitor the solar wind, and many numerical simulations.”

    Loureiro hastens to add that these results do not prove that the model is correct, but show that it is consistent with existing data. “Further research is definitely needed,” Loureiro says. “The theory makes specific, testable predictions, but these are difficult to check with current simulations and observations.”

    He adds, “The theory is quite universal, which increases the possibilities for direct tests.” For example, there is some hope that a new NASA mission, the Parker Solar Probe, which is planned for launch next year and will be observing the sun’s corona (the hot ring of plasma around the sun that is only visible from Earth during a total eclipse), could provide the needed evidence. That probe, Loureiro says, will be going closer to the sun than any previous spacecraft, and it should provide the most accurate data on turbulence in the corona so far.

    Collecting this information is well worth the effort, Loureiro says: “Turbulence plays a critical role in a variety of astrophysical phenomena,” including the flows of matter in the core of planets and stars that generate magnetic fields via a dynamo effect, the transport of material in accretion disks around massive central objects such as black holes, the heating of stellar coronae and winds (the gases constantly blown away from the surfaces of stars), and the generation of structures in the interstellar medium that fills the vast spaces between the stars. “A solid understanding of how turbulence works in a plasma is key to solving these longstanding problems,” he says.

    “This important study represents a significant step forward toward a deeper physical understanding of magnetized plasma turbulence,” says Dmitri Uzdensky, an associate professor of physics at the University of Colorado, who was not involved in this work. “By elucidating deep connections and interactions between two ubiquitous and fundamental plasma processes — magnetohydrodynamic turbulence and magnetic reconnection — this analysis changes our theoretical picture of how the energy of turbulent plasma motions cascades from large down to small scales.”

    He adds, “This work builds on a previous pioneering study published by these authors earlier this year and extends it into a broader realm of collisionless plasmas. This makes the resulting theory directly applicable to more realistic plasma environments found in nature. At the same time, this paper leads to new tantalizing questions about plasma turbulence and reconnection and thus opens new directions of research, hence stimulating future research efforts in space physics and plasma astrophysics.”

    The research was supported by a CAREER award from the National Science Foundation and the U.S. Department of Energy through the Partnership in Basic Plasma Science and Engineering.

    See the full article here .

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  • richardmitnick 7:55 am on November 28, 2017 Permalink | Reply
    Tags: , , Magnetic reconnection, , 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,   

    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.

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    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

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    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 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, Magnetic reconnection, , , ,   

    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 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, Magnetic reconnection, , , 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 8:36 pm on July 14, 2017 Permalink | Reply
    Tags: A high Mach number shock wave, High-energy plasma, , Magnetic reconnection, , 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.

    2
    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 .

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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 5:21 am on May 16, 2017 Permalink | Reply
    Tags: , , , Magnetic reconnection, Particle acceleration, , Rochester’s Laboratory for Laser Energetics,   

    From ALCF: “Fields and flows fire up cosmic accelerators” 

    Argonne Lab
    News from Argonne National Laboratory

    ANL Cray Aurora supercomputer
    Cray Aurora supercomputer at the Argonne Leadership Computing Facility

    MIRA IBM Blue Gene Q supercomputer at the Argonne Leadership Computing Facility
    MIRA IBM Blue Gene Q supercomputer at the Argonne Leadership Computing Facility

    ALCF

    May 15, 2017
    John Spizzirri

    1
    A visualization from a 3D OSIRIS simulation of particle acceleration in laser-driven magnetic reconnection. The trajectories of the most energetic electrons (colored by energy) are shown as the two magnetized plasmas (grey isosurfaces) interact. Electrons are accelerated by the reconnection electric field at the interaction region and escape in a fan-like profile. Credit: Frederico Fiuza, SLAC National Accelerator Laboratory/OSIRIS

    Every day, with little notice, the Earth is bombarded by energetic particles that shower its inhabitants in an invisible dusting of radiation, observed only by the random detector, or astronomer, or physicist duly noting their passing. These particles constitute, perhaps, the galactic residue of some far distant supernova, or the tangible echo of a pulsar. These are cosmic rays.

    But how are these particles produced? And where do they find the energy to travel unchecked by immense distances and interstellar obstacles?

    These are the questions Frederico Fiuza has pursued over the last three years, through ongoing projects at the Argonne Leadership Computing Facility (ALCF), a U.S. Department of Energy (DOE) Office of Science User Facility.

    A physicist at the SLAC National Accelerator Laboratory in California, Fiuza and his team are conducting thorough investigations of plasma physics to discern the fundamental processes that accelerate particles.

    The answers could provide an understanding of how cosmic rays gain their energy and how similar acceleration mechanisms could be probed in the laboratory and used for practical applications.

    While the “how” of particle acceleration remains a mystery, the “where” is slightly better understood. “The radiation emitted by electrons tells us that these particles are accelerated by plasma processes associated with energetic astrophysical objects,” says Fiuza.

    The visible universe is filled with plasma, ionized matter formed when gas is super-heated, separating electrons from ions. More than 99 percent of the observable universe is made of plasmas, and the radiation emitted from them creates the beautiful, eerie colors that accentuate nebulae and other astronomical wonders.

    The motivation for these projects came from asking whether it was possible to reproduce similar plasma conditions in the laboratory and study how particles are accelerated.

    High-power lasers, such as those available at the University of Rochester’s Laboratory for Laser Energetics or at the National Ignition Facility in the Lawrence Livermore National Laboratory, can produce peak powers in excess of 1,000 trillion watts.

    2
    Rochester’s Laboratory for Laser Energetics


    At these high-powers, lasers can instantly ionize matter and create energetic plasma flows for the desired studies of particle acceleration.

    Intimate Physics

    To determine what processes can be probed and how to conduct experiments efficiently, Fiuza’s team recreates the conditions of these laser-driven plasmas using large-scale simulations. Computationally, he says, it becomes very challenging to simultaneously solve for the large scale of the experiment and the very small-scale physics at the level of individual particles, where these flows produce fields that in turn accelerate particles.

    Because the range in scales is so dramatic, they turned to the petascale power of Mira, the ALCF’s Blue Gene/Q supercomputer, to run the first-ever 3D simulations of these laboratory scenarios. To drive the simulation, they used OSIRIS, a state-of-the-art, particle-in-cell code for modeling plasmas, developed by UCLA and the Instituto Superior Técnico, in Portugal, where Fiuza earned his PhD.

    Part of the complexity involved in modeling plasmas is derived from the intimate coupling between particles and electromagnetic radiation — particles emit radiation and the radiation affects the motion of the particles.

    In the first phase of this project, Fiuza’s team showed that a plasma instability, the Weibel instability, is able to convert a large fraction of the energy in plasma flows to magnetic fields. They have shown a strong agreement in a one-to-one comparison of the experimental data with the 3D simulation data, which was published in Nature Physics, in 2015. This helped them understand how the strong fields required for particle acceleration can be generated in astrophysical environments.

    Fiuza uses tennis as an analogy to explain the role these magnetic fields play in accelerating particles within shock waves. The net represents the shockwave and the racquets of the two players are akin to magnetic fields. If the players move towards the net as they bounce the ball between each other, the ball, or particles, rapidly accelerate.

    “The bottom line is, we now understand how magnetic fields are formed that are strong enough to bounce these particles back and forth to be energized. It’s a multi-step process: you need to start by generating strong fields — and we found an instability that can generate strong fields from nothing or from very small fluctuations — and then these fields need to efficiently scatter the particles,” says Fiuza.

    Reconnecting

    NASA Magnetic reconnection, Credit: M. Aschwanden et al. (LMSAL), TRACE, NASA

    But particles can be energized in another way if the system provides the strong magnetic fields from the start.

    “In some scenarios, like pulsars, you have extraordinary magnetic field amplitudes,” notes Fiuza. “There, you want to understand how the enormous amount of energy stored in these fields can be directly transferred to particles. In this case, we don’t tend to think of flows or shocks as the dominant process, but rather magnetic reconnection.”

    Magnetic reconnection, a fundamental process in astrophysical and fusion plasmas, is believed to be the cause of solar flares, coronal mass ejections, and other volatile cosmic events. When magnetic fields of opposite polarity are brought together, their topologies are changed. The magnetic field lines rearrange in such a way as to convert magnetic energy into heat and kinetic energy, causing an explosive reaction that drives the acceleration of particles. This was the focus of Fiuza’s most recent project at the ALCF.

    Again, Fiuza’s team modeled the possibility of studying this process in the laboratory with laser-driven plasmas. To conduct 3D, first-principles simulations (simulations derived from fundamental theoretical assumptions/predictions), Fiuza needed to model tens of billions of particles to represent the laser-driven magnetized plasma system. They modeled the motion of every particle and then selected the thousand most energetic ones. The motion of those particles was individually tracked to determine how they were accelerated by the magnetic reconnection process.

    “What is quite amazing about these cosmic accelerators is that a very, very small number of particles carry a large fraction of the energy in the system, let’s say 20 percent. So you have this enormous energy in this astrophysical system, and from some miraculous process, it all goes to a few lucky particles,” he says. “That means that the individual motion of particles and the trajectory of particles are very important.”

    The team’s results, which were published in Physical Review Letters, in 2016, show that laser-driven reconnection leads to strong particle acceleration. As two expanding plasma plumes interact with each other, they form a thin current sheet, or reconnection layer, which becomes unstable, breaking into smaller sheets. During this process, the magnetic field is annihilated and a strong electric field is excited in the reconnection region, efficiently accelerating electrons as they enter the region.

    Fiuza expects that, like his previous project, these simulation results can be confirmed experimentally and open a window into these mysterious cosmic accelerators.

    This research is supported by the DOE Office of Science. Computing time at the ALCF was allocated through the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program.

    See the full article here .

    Please help promote STEM in your local schools.
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    Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science. For more visit http://www.anl.gov.

    About ALCF

    The Argonne Leadership Computing Facility’s (ALCF) mission is to accelerate major scientific discoveries and engineering breakthroughs for humanity by designing and providing world-leading computing facilities in partnership with the computational science community.

    We help researchers solve some of the world’s largest and most complex problems with our unique combination of supercomputing resources and expertise.

    ALCF projects cover many scientific disciplines, ranging from chemistry and biology to physics and materials science. Examples include modeling and simulation efforts to:

    Discover new materials for batteries
    Predict the impacts of global climate change
    Unravel the origins of the universe
    Develop renewable energy technologies

    Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science

    Argonne Lab Campus

     
  • richardmitnick 2:42 pm on April 10, 2017 Permalink | Reply
    Tags: , , , , European Space Agency’s Cluster satellites, Magnetic reconnection   

    From AGU: “For Magnetic Reconnection Energy, O—not X—Might Mark the Spot” 

    AGU bloc

    American Geophysical Union

    1
    Artist’s illustration of events on the Sun changing the conditions in near-Earth space. Credit: NASA

    4.10.17
    Mark Zastrow
    mark.zastrow@gmail.com

    Magnetic reconnection is one of the most important—and least understood—processes in all of space physics.

    NASA Magnetic reconnection, Credit: M. Aschwanden et al. (LMSAL), TRACE, NASA

    It happens at the boundaries of Earth’s magnetic field, where it meets the Sun’s, causing magnetic field lines to break and realign in an explosive manner that can generate hazardous radiation, especially during solar storms. Now a new study from Fu et al [Geophysical Research Lettersl . adds weight to suggestions that scientists have been looking for this energy in the wrong type of reconnection.

    For decades, the classic introductory textbook picture of magnetic reconnection has depicted two parallel lines that pull themselves together into an X shape, as if pinched together, until they finally touch at the center of the X line. Then, the field lines snap and realign. Like a rebounding rubber band, they fling plasma out from the center of the X, generating currents than can surge down into the Earth’s magnetic field. During high solar activity, this process generates the dangerous radiation that threatens power grids, satellite communications, and the health of astronauts.

    1
    At reconnection O lines (usually referred to as magnetic islands or flux ropes in spacecraft data), there is strong current, turbulence, and energy dissipation. At reconnection X lines, there is no current, turbulence, or energy dissipation. Credit: Huishan Fu

    At least, that is the conventional wisdom. But that’s not what the authors’ analysis shows. Instead, the intense blasts of energy may come from a different kind of magnetic reconnection, one not as often shown in textbooks: so-called O lines, where the approaching field lines spiral and swirl together, as if caught in a whirlpool.

    The team analyzed data from the European Space Agency’s Cluster satellites, a quartet of spacecraft launched in 2000 that fly in formation—sometimes less than 10 kilometers apart—which allows them to make detailed measurements from within magnetic reconnection events.

    4
    European Space Agency’s Cluster satellites

    In particular, the authors examined a pass through a magnetic storm on 9 October 2003, high over Earth’s nightside.

    During their pass through this storm, the craft flew within a few hundred kilometers of several potential sites of reconnection. The team used computer models to recreate the topology of the field lines, finding that two of them were X lines and the rest were O lines. But instead of seeing the highest current levels at X lines as expected, the team found most of the greatest current spikes to be near O lines. At the X lines, the current was almost nonexistent.

    The team writes that their results clearly show that O lines, not X lines, are responsible for energy dissipation in reconnection, a result that is likely to spark a great deal of discussion. (Geophysical Research Letters, https://doi.org/10.1002/2016GL071787, 2017)

    See the full post here .

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    The purpose of the American Geophysical Union is to promote discovery in Earth and space science for the benefit of humanity.

    To achieve this mission, AGU identified the following core values and behaviors.

    Core Principles

    As an organization, AGU holds a set of guiding core values:

    The scientific method
    The generation and dissemination of scientific knowledge
    Open exchange of ideas and information
    Diversity of backgrounds, scientific ideas and approaches
    Benefit of science for a sustainable future
    International and interdisciplinary cooperation
    Equality and inclusiveness
    An active role in educating and nurturing the next generation of scientists
    An engaged membership
    Unselfish cooperation in research
    Excellence and integrity in everything we do

    When we are at our best as an organization, we embody these values in our behavior as follows:

    We advance Earth and space science by catalyzing and supporting the efforts of individual scientists within and outside the membership.
    As a learned society, we serve the public good by fostering quality in the Earth and space science and by publishing the results of research.
    We welcome all in academic, government, industry and other venues who share our interests in understanding the Earth, planets and their space environment, or who seek to apply this knowledge to solving problems facing society.
    Our scientific mission transcends national boundaries.
    Individual scientists worldwide are equals in all AGU activities.
    Cooperative activities with partner societies of all sizes worldwide enhance the resources of all, increase the visibility of Earth and space science, and serve individual scientists, students, and the public.
    We are our members.
    Dedicated volunteers represent an essential ingredient of every program.
    AGU staff work flexibly and responsively in partnership with volunteers to achieve our goals and objectives.

     
  • richardmitnick 7:39 am on April 1, 2017 Permalink | Reply
    Tags: Magnetic reconnection, MPIPP,   

    From PPPL and Max Planck Institute of Plasma Physics via phys.org: “Physicists reveal experimental verification of a key source of fast reconnection of magnetic fields” 


    PPPL

    MPIPP bloc

    Max Planck Institute for Plasma Physics

    March 31, 2017

    1
    Physicist Will Fox with Magnetic Reconnection Experiment. Credit: Elle Starkman/PPPL Office of Communications

    Magnetic reconnection, a universal process that triggers solar flares and northern lights and can disrupt cell phone service and fusion experiments, occurs much faster than theory says that it should. Now researchers at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) and Germany’s Max Planck Institute of Plasma Physics have discovered a source of the speed-up in a common form of reconnection. Their findings could lead to more accurate predictions of damaging space weather and improved fusion experiments.

    Reconnection occurs when the magnetic field lines in plasma—the collection of atoms and charged electrons and atomic nuclei, or ions, that make up 99 percent of the visible universe—converge and forcefully snap apart. Electrons that exert a varying degree of pressure form an important part of this process as reconnection takes place.

    The research team found that variation in the electron pressure develops along the magnetic field lines in the region undergoing reconnection. This variation balances and keeps a strong electric current inside the plasma from growing out of control and halting the reconnection process. It is this balancing act that makes possible fast reconnection.

    “The main issue we addressed is how reconnection can take place so quickly,” said Will Fox, lead author of a paper that detailed the findings in March in the journal Physical Review Letters. “Here we’ve shown experimentally how electron pressure accelerates the process.”

    The physics team built a picture of the gradient and other parameters of reconnection from research conducted on the Magnetic Reconnection Experiment (MRX) at PPPL, the leading laboratory device for studying reconnection. The findings marked the first experimental confirmation of predictions made by earlier simulations performed by other researchers of the behavior of ions and electrons during reconnection. “The experiments demonstrate how the plasma can sustain a large electric field while preventing a large electric current from building up and halting the reconnection process,” said Fox.

    Among potential applications of the results:

    Predictions of space storms. Magnetic reconnection in the magnetosphere, the magnetic field that surrounds the Earth, can set off geomagnetic “substorms” that disable communications and global positioning satellites (GPS) and disrupt electrical grids. Improved understanding of fast reconnection can help locate regions where the process triggering storms is ready to take place.
    Mitigation of the impact. Advanced warning of reconnection and the disruptions that may follow can lead to steps to protect sensitive satellite systems and electric grids.
    Improvement of fusion facility performance. The process observed in MRX likely plays a key role in producing what are called “sawtooth” instabilities that can halt fusion reactions. Understanding the process could open the door to controlling it and limiting such instabilities. “How sawtooth happens so fast has been a mystery that this research helps to explain,” said Fox. “In fact, it was computer simulations of sawtooth crashes that first linked electron pressure to the source of fast reconnection.”

    See the full article here .

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    MPIPP campus

    The Max Planck Institute of Plasma Physics (Max-Planck-Institut für Plasmaphysik, IPP) is a physics institute for the investigation of plasma physics, with the aim of working towards fusion power. The institute also works on surface physics, also with focus on problems of fusion power.

    The IPP is an institute of the Max Planck Society, part of the European Atomic Energy Community, and an associated member of the Helmholtz Association.

    The IPP has two sites: Garching near Munich (founded 1960) and Greifswald (founded 1994), both in Germany.

    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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