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  • richardmitnick 2:09 pm on December 7, 2018 Permalink | Reply
    Tags: Magnetic reconnection, Magnetospheric Multiscale Satellite (MMS) mission launched in 2015, , , Princeton Magnetic Reconnection Experiment (MRX) at PPPL   

    From PPPL: “Experiments at PPPL show remarkable agreement with satellite sightings” 


    From PPPL

    December 7, 2018
    John Greenwald

    1
    Members of the MRX team with the device in the background. From left, Masaaki Yamada, Jongsoo Yoo, Jonathan Jara-Almonte, Will Fox, and Hantao Ji.
    (Photo by Elle Starkman/PPPL Office of Communications)

    1
    Illustration of the MMS spacecraft in orbit in Earth’s magnetic field. NASA

    As on Earth, so in space. A four-satellite mission that is studying magnetic reconnection — the breaking apart and explosive reconnection of the magnetic field lines in plasma that occurs throughout the universe — has found key aspects of the process in space to be strikingly similar to those found in experiments at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL). The similarities show how the studies complement each other: The laboratory captures important global features of reconnection and the spacecraft documents local key properties as they occur.

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

    The observations made by the Magnetospheric Multiscale Satellite (MMS) mission, which NASA launched in 2015 to study reconnection in the magnetic field that surrounds the Earth, correspond quite well with past and present laboratory findings of the Magnetic Reconnection Experiment (MRX) at PPPL. Previous MRX research uncovered the process by which rapid reconnection occurs and identified the amount of magnetic energy that is converted to particle energy during the process, which gives rise to northern lights, solar flares and geomagnetic storms that can disrupt cell phone service, black out power grids and damage orbiting satellites.

    Guidelines for MMS measurements

    The previous MRX findings served as guidelines for measurements taken by the MMS mission, which seeks to understand the region in which the reconnection of field lines in plasma — the state of matter composed of free electrons and atomic nuclei, or ions — takes place. The latest PPPL experiments extend the findings to new areas of agreement. “Despite huge differences in the size of the reconnection layers in the MRX and in space, remarkably similar characteristics are observed in both,” said Masaaki Yamada, principal investigator on the MRX, and lead author of the recent paper reporting the results in the December 6 edition of Nature Communications .

    The past laboratory research examined “symmetric” reconnection, in which the density of the plasmas on each side of the reconnection regions are roughly the same. The new paper looks at reconnection in the magnetopause — the outer region of the magnetosphere — and in the MRX that is “asymmetric,” meaning that the plasma on one side of the region is at least 10 times denser than on the other. The MMS mission has focused its initial research on the asymmetric aspect of reconnection, since the plasma in the solar wind — the charged particles flowing from the sun — is vastly denser than the plasma in the magnetosphere.

    In the new paper, researchers examine what is called the “two-fluid” physics of reconnection that describes each behavior of ions and electrons differently during the process. Such physics dominates magnetic reconnection in both MRX and magnetospheric plasma systems, allowing for an unprecedented level of cross-examination between laboratory measurements and space observations.

    Key findings

    Following are key findings of the two-fluid, asymmetric research on MRX that is shown to be in striking agreement with measurements of electron and ion behavior by the space satellites and the conversion of magnetic energy to particle energy. Computer simulations aided these findings:

    • Electrons. The experiments demonstrated that electron current flows perpendicular, and not parallel as once thought, to the magnetic field. This flow is key to the conversion of magnetic energy in electrons that occurs in a narrow boundary layer called the “electron diffusion region” where rapid reconnection takes place. The finding is consistent with the recent MMS space measurements and new in the laboratory for asymmetric reconnection.

    • Ions. The ion current also flows perpendicular to the magnetic field as in the electron case, and likewise is key to the conversion of ion magnetic energy to particle energy. For ions, this conversion occurs in the wider “ion diffusion region” between converging plasmas and is a similarly recent finding about asymmetric reconnection in laboratory plasmas.

    The MRX experiments further studied different aspects of conversion in the symmetric and asymmetric cases. In symmetric reconnection, 50 percent of magnetic energy was previously found to be converted to ions and electrons, with one-third of the conversion affecting the electrons and two-thirds accelerating the ions. The total conversion rate remains roughly the same in the asymmetric case, as does the ratio of energy conversion for ions and electrons.

    PPPL researchers contributing to this study were Jongsoo Yoo, Will Fox, Jonathan Jara-Almote and Hantao Ji. Also contributing were physicists at the NASA Goddard Space Flight Center, Los Alamos National Laboratory, the Southwest Research Institute, and the universities of New Hampshire and Bergen in Bergen, Norway. Computer simulations were conducted at Los Alamos National Laboratory. Support for this work comes from DOE’s Office of Science, NASA, and the National Science Foundation.

    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 1:27 pm on October 24, 2018 Permalink | Reply
    Tags: Biermann battery effect, , Magnetic reconnection, , ,   

    From COSMOS Magazine: “Supercomputer finds clues to violent magnetic events” 

    Cosmos Magazine bloc

    From COSMOS Magazine

    24 October 2018
    Phil Dooley

    1
    An aurora over Iceland, the product of sudden magnetic reconnection. Credit Natthawat/Getty Images

    Researchers are a step closer to understanding the violent magnetic events that cause the storms on the sun’s surface and fling clouds of hot gas out into space, thanks to colossal computer simulations at Princeton University in the US.

    The disruptions in the magnetic field, known as magnetic reconnections, are common in the universe – the same process causes the aurora in high latitude skies – but existing models are unable to explain how they happen so quickly.

    A team led by Jackson Matteucci decided to investigate by building a full three-dimensional simulation of the ejected hot gas, something that required enormous computing power. The results are published in the journal Physical Review Letters.

    The researchers modelled more than 200 million particles using Titan, the biggest supercomputer [no longer true, the writer should have known that] in the US.

    ORNL Cray Titan XK7 Supercomputer, once the fastest in the world.

    They discovered that a three-dimensional interaction called the Biermann battery effect was at the heart of the sudden reconnection process.

    Discovered in the fifties by German astrophysicist Ludwig Biermann, the Biermann battery effect shows how magnetic fields can be generated in charged gases, known as plasma.

    In such plasmas, if a region develops in which there is a temperature gradient at right angles to a density gradient, a magnetic field is created that encircles it.

    Astrophysicists propose that this effect might take place in interstellar plasma clouds, such as nebulae, and generate the cosmic magnetic fields that we see throughout the universe.

    In contrast with the huge scale of cosmic plasma clouds, magnetic reconnection happens at a scale of microns when two magnetic fields collide, says Matteucci.

    He likens the process to collisions between two sizable handfuls of rubber bands. In stable circumstances the magnetic field lines are loops, like the bands. But sometimes turbulence in the plasma pushes these band analogues together so forcefully that they sever and reconnect to different ones, thus forming loops at different orientations.

    Some of the new loops are stretched taut and snap back, providing the energy that ejects material so violently, and causes magnetic storms or glowing auroras.

    The Princeton simulation showed that as the fields collide there is a sudden spike in the temperature in a very localised region, which sets off the Biermann battery effect, suddenly creating a new magnetic field in the midst of the collision. It’s this newly-appearing field that severs the lines and allows them to reconfigure.

    Although Matteucci’s simulations are for tiny plasma clouds generated by lasers hitting foil, he says they could help us understand large-scale processes in the atmosphere.

    “If you do a back of the envelope calculation, you find it could play an important role in reconnection in the magnetosphere, where the solar wind collides with the Earth’s magnetic field,” he says.

    See the full article here .


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  • richardmitnick 7:21 pm on October 16, 2018 Permalink | Reply
    Tags: , , Magnetic reconnection, , MIT Plasma Science and Fusion Center, Nuno Loureiro, Physicist explores the behavior of the universe’s most abundant form of matter, Physics of plasmas, Plasma is a sort of fourth phase of matter, The solar wind is the best plasma turbulence laboratory we have, Turbulence-a major stumbling block so far to practical fusion power   

    From MIT News-“Nuno Loureiro: Probing the world of plasmas” 

    MIT News
    MIT Widget

    From MIT News

    October 15, 2018
    David L. Chandler

    1
    A major motivation for moving to MIT from his research position, Nuno Loureiro says, was working with students. Image: Jared Charney

    Physicist explores the behavior of the universe’s most abundant form of matter.

    Growing up in the small city of Viseu in central Portugal, Nuno Loureiro knew he wanted to be a scientist, even in the early years of primary school when “everyone else wanted to be a policeman or a fireman,” he recalls. He can’t quite place the origin of that interest in science: He was 17 the first time he met a scientist, he says with an amused look.

    By the time Loureiro finished high school, his interest in science had crystallized, and “I realized that physics was what I liked best,” he says. During his undergraduate studies at the IST Lisbon, he began to focus on fusion, which “seemed like a very appealing field,” where major developments were likely during his lifetime, he says.

    Fusion, and specifically the physics of plasmas, has remained his primary research focus ever since, through graduate school, postdoc stints, and now in his research and teaching at MIT. He explains that plasma research “lives in two different worlds.” On the one hand, it involves astrophysics, dealing with the processes that happen in and around stars; on the other, it’s part of the quest to generate electricity that’s clean and virtually inexhaustible, through fusion reactors.

    Plasma is a sort of fourth phase of matter, similar to a gas but with the atoms stripped apart into a kind of soup of electrons and ions. It forms about 99 percent of the visible matter in the universe, including stars and the wispy tendrils of material spread between them. Among the trickiest challenges to understanding the behavior of plasmas is their turbulence, which can dissipate away energy from a reactor, and which proceeds in very complex and hard-to-predict ways — a major stumbling block so far to practical fusion power.

    While everyone is familiar with turbulence in fluids, from breaking waves to cream stirred into coffee, plasma turbulence can be quite different, Loureiro explains, because plasmas are riddled with magnetic and electric fields that push and pull them in dynamic ways. “A very noteworthy example is the solar wind,” he says, referring to the ongoing but highly variable stream of particles ejected by the sun and sweeping past Earth, sometimes producing auroras and affecting the electronics of communications satellites. Predicting the dynamics of such flows is a major goal of plasma research.

    “The solar wind is the best plasma turbulence laboratory we have,” Loureiro says. “It’s increasingly well-diagnosed, because we have these satellites up there. So we can use it to benchmark our theoretical understanding.”

    Loureiro began concentrating on plasma physics in graduate school at Imperial College London and continued this work as a postdoc at the Princeton Plasma Physics Laboratory and later the Culham Centre for Fusion Energy, the U.K.’s national fusion lab. Then, after a few years as a principal researcher at the University of Portugal, he joined the MIT faculty at the Plasma Science and Fusion Center in 2016 and earned tenure in 2017. A major motivation for moving to MIT from his research position, he says, was working with students. “I like to teach,” he says. Another was the “peerless intellectual caliber of the Plasma Science and Fusion Center at MIT.”

    Loureiro, who holds a joint appointment in MIT’s Department of Physics, is an expert on a fundamental plasma process called magnetic reconnection. One example of this process occurs in the sun’s corona, a glowing irregular ring that surrounds the disk of the sun and becomes visible from Earth during solar eclipses. The corona is populated by vast loops of magnetic fields, which buoyantly rise from the solar interior and protrude through the solar surface. Sometimes these magnetic fields become unstable and explosively reconfigure, unleashing a burst of energy as a solar flare. “That’s magnetic reconnection in action,” he says.

    Over the last couple of years at MIT, Loureiro published a series of papers with physicist Stanislav Boldyrev at the University of Wisconsin, in which they proposed a new analytical model to reconcile critical disparities between models of plasma turbulence and models of magnetic reconnection. It’s too early to say if the new model is correct, he says, but “our work prompted a reanalysis of solar wind data and also new numerical simulations. The results from these look very encouraging.”

    Their new model, if proven, shows that magnetic reconnection must play a crucial role in the dynamics of plasma turbulence over a significant range of spatial scales – an insight that Loureiro and Boldyrev claim would have profound implications.

    Loureiro says that a deep, detailed understanding of turbulence and reconnection in plasmas is essential for solving a variety of thorny problems in physics, including the way the sun’s corona gets heated, the properties of accretion disks around black holes, nuclear fusion, and more. And so he plugs away, to continue trying to unravel the complexities of plasma behavior. “These problems present beautiful intellectual challenges,” he muses. “That, in itself, makes the challenge worthwhile. But let’s also keep in mind that the practical implications of understanding plasma behavior are enormous.”

    See the full article here .


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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 8:54 am on May 2, 2018 Permalink | Reply
    Tags: , , , , , Magnetic reconnection,   

    From Chalmers University of Technology: “Flares in the universe can now be studied on earth” 

    Chalmers University of Technology

    02 May 2018

    Tünde Fülöp
    Professor, Department of Physics, Chalmers University of Technology
    +46 72 986 74 40
    tunde.fulop@chalmers.se

    Longqing Yi
    Postdoctoral researcher,Department of Physics,Chalmers University of Technology
    +46 31 772 68 82
    longqing@chalmers.se

    1
    Solar flares are caused by magnetic reconnection in space and can interfere with our communications satellites, affecting power grids, air traffic and telephony. Now, researchers at Chalmers University of Technology, Sweden, have found a new way to imitate and study these spectacular space plasma phenomena in a laboratory environment. Image: NASA/SDO/AIA/Goddard Space Flight Center

    NASA/SDO

    3
    Longqing Yi
    4
    Tünde Fülöp

    Solar flares, cosmic radiation, and the northern lights are well-known phenomena. But exactly how their enormous energy arises is not as well understood. Now, physicists at Chalmers University of Technology, Sweden, have discovered a new way to study these spectacular space plasma phenomena in a laboratory environment. The results have been published in the renowned journal Nature Communications.

    “Scientists have been trying to bring these space phenomena down to earth for a decade. With our new method we can enter a new era, and investigate what was previously impossible to study. It will tell us more about how these events occur,” says Longqing Yi, researcher at the Department of Physics at Chalmers.

    The research concerns so-called ‘magnetic reconnection’ – the process which gives rise to these phenomena. Magnetic reconnection causes sudden conversion of energy stored in the magnetic field into heat and kinetic energy. This happens when two plasmas with anti-parallel magnetic fields are pushed together, and the magnetic field lines converge and reconnect. This interaction leads to violently accelerated plasma particles that can sometimes be seen with the naked eye – for example, during the northern lights.

    Magnetic reconnection in space can also influence us on earth. The creation of solar flares can interfere with communications satellites, and thus affect power grids, air traffic and telephony.

    In order to imitate and study these spectacular space plasma phenomena in the laboratory, you need a high-power laser, to create magnetic fields around a million times stronger than those found on the surface of the sun. In the new scientific article, Longqing Yi, along with Professor Tünde Fülöp from the Department of Physics, proposed an experiment in which magnetic reconnection can be studied in a new, more precise way. Through the use of ‘grazing incidence’ of ultra-short laser pulses, the effect can be achieved without overheating the plasma. The process can thus be studied very cleanly, without the laser directly affecting the internal energy of the plasma. The proposed experiment would therefore allow us to seek answers to some of the most fundamental questions in astrophysics.

    “We hope that this can inspire many research groups to use our results. This is a great opportunity to look for knowledge that could be useful in a number of areas. For example, we need to better understand solar flares, which can interfere with important communication systems. We also need to be able to control the instabilities caused by magnetic reconnection in fusion devices,” says Tünde Fülöp.

    The study on which the new results are based was financed by the Knut and Alice Wallenberg foundation, through the framework of the project ‘Plasma-based Compact Ion Sources’, and the ERC project ‘Running away and radiating’.

    4
    Schematic of the proposed setup and relativistic jets generation. a A moderately high-intensity laser pulse (a0 = 5) propagates along the x-direction, and is splitted in half by a micro-sized plasma slab. The laser drives two energetic electron beams on both sides of the plasma surfaces, which generate 100 MG level opposing azimuthal magnetic fields in the middle. Ultrafast magnetic reconnection is observed as the electron beams approach the coronal region (the area within the blue box, where the plasma density decreases exponentially) at the end of the slab. The two insets below show the transverse magnetic fields (black arrows) and longitudinal electric current density (color) at the cross-section marked by the red rectangle (separated by 10λ0) at simulation times t = 24T0 and t = 34T0, respectively. b–e Generation and evolution of the relativistic jet resulting from MR at times 32T0, 35T0, 38T0, and 41T0, respectively. The rainbow color bar shows the transverse momentum P z of the jets formed by the background plasma electrons in b–e, and the blue-red color bar shows the energy of the electron bunch driven by the laser pulse in b, c.

    5
    Gyrotropy quantification at different times. Square root of quantified pressure tensor agyrotropy Q−−√ in the coronal plasma at simulation time t = 32T0(a), 33T0(b), and 34T0(c). The insets show the value of Q−−√ at the cross-section with longitudinal coordinate x = 26λ0, which is marked by the red rectangles in a–c.

    6
    Evolution of magnetic fields and magnetic tension force during the reconnection. a–c Static magnetic fields (frequency below 0.8ω0) and d–f z-component of magnetic tension force at simulation time t = 32T0 (a, d), 33T0 (b, e), and 34T0 (c, f). In a–c the transverse (B y , B z ) and longitudinal (B x ) components of magnetic field are presented by the black arrows and color, respectively. The bold white arrows in b show the inflow (horizontal) and outflow (vertical) electric currents that result from Hall reconnection. The black-dashed lines in d–f mark the cross-section where the corresponding magnetic fields (a–c) are shown.

    7
    Magnetic energy dissipation and the energization of non-thermal electrons. a Field dissipation (E x j x ) and electron density at t = 33T0 in the corona, the insets represent the top and side views of E x j x in the reconnection site (marked by the red box). b Time dependence of total energy increase in electrostatic fields, electrons in the corona, and protons (ΔE+), energy reduction of electromagnetic fields and other electrons (ΔE−), as well as the total energy reduction that includes magnetic field dissipation (ΔE− + ΔEm), inset shows the evolution of static magnetic energy Em and total kinetic energy of electron jets. c Coronal electron spectra from 30T0 to 36T0. d The temporal evolution of the kinetic energy (Ek) and the work done by each electric field component (W x , W y , and W z ) for one representative electron. The inset plane shows the phase-space trajectory (γ − 1 plotted vs. y) of the total 100 tracked electrons, where the blue-dashed line marks the boundary of plasma slab and the trajectory in red represents the case shown in d.

    Text:
    Mia Halleröd Palmgren,
    mia.hallerodpalmgren@chalmers.se

    Translation:
    Joshua Worth, joshua.worth@chalmers.se

    See the full article here .

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    Chalmers University of Technology (Swedish: Chalmers tekniska högskola, often shortened to Chalmers) is a Swedish university located in Gothenburg that focuses on research and education in technology, natural science, architecture, maritime and other management areas

    The University was founded in 1829 following a donation by William Chalmers, a director of the Swedish East India Company. He donated part of his fortune for the establishment of an “industrial school”. Chalmers was run as a private institution until 1937, when the institute became a state-owned university. In 1994, the school was incorporated as an aktiebolag under the control of the Swedish Government, the faculty and the Student Union. Chalmers is one of only three universities in Sweden which are named after a person, the other two being Karolinska Institutet and Linnaeus University.

     
  • richardmitnick 4:13 pm on March 16, 2018 Permalink | Reply
    Tags: , FLARE- Facility for Laboratory Reconnection Experiment, Magnetic reconnection, Plasma — the fourth state of matter, ,   

    From PPPL: “First plasma for new machine to study process that occurs throughout the universe” 


    PPPL

    March 16, 2018
    John Greenwald

    PPPL FLARE – Facility for Laboratory Reconnection Experiment

    The first plasma, a milestone event signaling the beginning of research capabilities, was captured on camera on Sunday, March 5, at 8:13 p.m. at Jadwin Hall at Princeton University, and marked completion of the four-year construction of the device, the Facility for Laboratory Reconnection Experiment (FLARE).
    Photo by Larry Bernard, Princeton Plasma Physics Laboratory

    A millisecond burst of light on a computer monitor signaled production of the first plasma in a powerful new device for advancing research into magnetic reconnection — a critical but little understood process that occurs throughout the universe.

    The first plasma, a milestone event signaling the beginning of research capabilities, was captured on camera on Sunday, March 5, at 8:13 p.m. at Jadwin Hall at Princeton University, and marked completion of the four-year construction of the device, the Facility for Laboratory Reconnection Experiment (FLARE).

    Magnetic reconnection, the breaking apart and explosive recombination of the magnetic field lines in hot plasma — the fourth state of matter composed of free electrons and atomic nuclei that makes up 99 percent of the visible universe — has impact throughout the cosmos. Reconnection gives rise to Northern Lights, solar eruptions and geomagnetic storms that can disrupt electrical networks and signal transmissions such as cellphone service. In laboratories where scientists are trying to create a “star on earth,” the process can degrade and even disrupt fusion experiments.

    Constructing FLARE, designed as a user facility for multiple institutions, was a team of physicists, engineers, designers, technicians and supporting staff for PPPL and Princeton, where the device was assembled. Support for construction of the project, whose future is being developed, came from the National Science Foundation with contributions from Princeton, the University of Maryland and the University of Wisconsin-Madison, with collaborators from Los Alamos National Laboratory, the University of California campuses at Berkeley and Los Angeles, and the Institute of Plasma Physics, Chinese Academy of Sciences.

    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 3:05 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.


    NASA/Goddard Campus

     
  • 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.”

    1
    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.

    3
    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?”

    4
    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.

    2
    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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    MIT Seal

    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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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.

    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 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.

     
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