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  • richardmitnick 3:40 pm on April 10, 2017 Permalink | Reply
    Tags: , , , , , Solar research   

    From NJIT: Putting Students Closer to Explosive Solar Events 

    NJIT Bloc

    New Jersey Institute of Technology

    1

    April 6, 2017

    NJIT has a long-established reputation as a leader in researching phenomena originating on the star closest to Earth — the Sun. NJIT’s optical telescope at Big Bear Solar Observatory and radio telescope array at Owens Valley, both in California, have greatly expanded our understanding of solar events that periodically impact our home planet, events such as solar flares and coronal mass ejections (CMEs) that can disrupt terrestrial communications and power infrastructure in addition to other effects.

    NJIT Big Bear Solar Observatory, located on the north side of Big Bear Lake in the San Bernardino Mountains of southwestern San Bernardino County, California, approximately 120 kilometers east of downtown Los Angeles

    Ten antennas of NJIT’s 13-antenna Expanded Owens Valley Solar Array (EOVSA)

    Under the auspices of the university’s Center for Solar-Terrestrial Research (CSTR), NJIT investigators are collaborating with colleagues in the U.S. and other countries to gain even more critical knowledge of solar physics. It’s knowledge essential not only for better basic understanding of the Sun but also to improve prediction of the solar explosions that threaten our technologies and to devise better countermeasures.

    What’s more, NJIT researchers are committed to fully engaging students in the search for this knowledge — researchers like Assistant Professor of Physics Bin Chen, who joined the NJIT faculty in 2016. Chen was recently awarded a five-year CAREER grant totaling more than $700,000 by the National Science Foundation (NSF). The NSF’s Faculty Early Career Development (CAREER) program offers the foundation’s most prestigious awards in support of younger faculty who, in building their academic careers, have demonstrated outstanding potential as both educators and researchers.

    Chen completed his Ph.D. at the University of Virginia in 2013 with a focus on solar radio astronomy. His Ph.D. advisor introduced him to fellow solar astronomer, and now NJIT colleague, Distinguished Professor of Physics Dale Gary. Through his acquaintance with Gary, and the opportunity to collaborate on a research project using observational data from NJIT’s Owens Valley Solar Array, Chen learned about the university’s leading-edge efforts in solar radio physics. But before he joined NJIT after receiving his doctorate, Chen added to his research experience through a postdoctoral fellowship under NASA’s Living With a Star program and as an astrophysicist at the Harvard Smithsonian Center for Astrophysics, where he worked on space missions dedicated primarily to solar science.

    Shocking Insights

    Although not yet fellow faculty members at NJIT, Chen and Gary did collaborate with researchers from the National Radio Astronomy Observatory, the University of California, the University of Applied Sciences and Arts Northwestern Switzerland and the University of Minnesota on an article for the journal Science published in 2015, Particle Acceleration by a Solar Flare Termination Shock. The article presented radio imaging data that provides new insights into how a phenomenon known as termination shock associated with solar flares, the most powerful explosions in the solar system, helps to accelerate energetic electrons in the flares to relativistic speeds — propelling these particles into space at nearly the speed of light.

    Chen is now continuing this investigation at NJIT. “There is a lot we don’t know about the ‘inside’ of these solar explosions and how they release so much energy so quickly and so catastrophically,” he says. “For example, how is the energy stored and suddenly released, often in a matter of seconds?

    “The relativistic particle acceleration that we are also studying as part of this research is a process taking place across the universe and is a phenomenon associated with, for example, the massive star explosions known as supernovae. The Sun is a good place to research this phenomenon because its nearness in astronomical terms allows us to acquire a volume of high-resolution data impossible to obtain from observing vastly more distant stars.”

    For his research, Chen is drawing on streams of radio data from a number of sources. In addition to NJIT’s radio observatory at Owens Valley, these include the Karl G. Jansky Very Large Array in New Mexico operated by the National Radio Astronomy Observatory and the Atacama Large Millimeter/Submillimeter Array in Chile.

    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    Recent upgrades at Owens Valley put it at the forefront of this research as a “new-generation” radio telescope. Another very important advantage afforded by Owens Valley, as Chen emphasizes, is that it is a facility dedicated full-time to solar research.

    Chen is one of the few researchers seeking new knowledge of the Sun by taking advantage of an observing technique called dynamic spectroscopy imaging. This technique allows capturing an image of the Sun every 50 milliseconds at more than a thousand frequencies, and at two different polarizations. This adds up to 40,000 images per second and terabytes of raw data in a day that can be converted into 3D images with resolution far greater than previously obtainable. “This gives us the potential to learn so much more about what is going on in the heart of solar explosions,” Chen says.

    Beyond greater understanding of the fundamental physics involved, Chen adds that his research is very much supportive of the goals of the U.S. National Space Weather Strategy and Action Plan, which reflects critical awareness of how space weather generated by solar phenomena impacts many aspects of terrestrial life and infrastructure. He says, “Solar flares and CMEs are the main drivers of space weather. Better understanding of these drivers is essential for better prediction of such events and the implementation of protective measures.”

    Bringing the Sun to Campus

    In Chen’s estimation, NJIT is uniquely experienced in building, operating and maintaining facilities dedicated to radio observation of the Sun. Potentially, for students, this presents exceptional opportunities to learn at the frontier of the many disciplines relevant to investigating the Sun in the radio spectrum — including hands-on familiarity with the equipment involved. While a limited number of students do have a chance to work at Owens Valley, as well as at Big Bear, distance and lack of appropriate accommodations prevent many more from participating in solar research on site. That’s why Chen also plans to apply a portion of his CAREER funding to creating a Solar Radio Laboratory on campus in Newark.

    “The idea behind the Solar Radio Laboratory is to have a facility on campus with the same state-of-the-art technology found at Owens Valley, just without the antennas,” Chen explains. “We’ll have all the electronics, the radio technology, the data-science capability for processing data streaming from California. This will give students the same hands-on opportunities for working and experimenting with the instrumentation that NJIT has at Owens Valley, instrumentation that is really unique in the United States. Another goal is to use this as a test bed for future improvements at Owens Valley, and to engage students in developing those improvements.”

    For Chen, a complementary educational goal is to also advance the Hale COLLAborative Graduate Education (COLLAGE) program in solar physics, which commemorates the name of the pioneering American solar astronomer George Ellery Hale. There are very few graduate programs in this field in the U.S. and the necessary faculty and physical resources are widely distributed across educational institutions as well as geography. To address this situation, Philip Goode, NJIT distinguished research professor of physics and former CSTR director, proposed that NJIT join with the University of Colorado-Boulder and several other institutions that had solar physics programs in what is now known as the COLLAGE program.

    “COLLAGE gives more students in different parts of the country access to the instruction and resources that allow them to complete master’s and Ph.D. degrees in solar physics,” Chen says. “I am already working with some 20 students, and that’s actually quite a large number for our field. But not only are we increasing opportunities to study solar physics at the graduate level, we’re learning more about coordinating resources among schools and teaching effectively online, which will benefit students who want to study many different complex subjects.”

    See the full article here .

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    NJIT campus

    Welcome to the New Jersey Institute of Technology. We’re proud of our 130 years of history, but that’s only the beginning of our story – we’ve doubled the size of our campus in the last decade, pouring millions into major new research facilities to give our students the edge they need in today’s demanding high-tech marketplace.

    NJIT offers 125 undergraduate and graduate degree programs in six specialized schools instructed by expert faculty, 98 percent of whom hold the highest degree in their field.

    Our academic programs are fully accredited by the appropriate accrediting boards, commissions and associations such as Middle States, ABET, and NAAB.

     
  • richardmitnick 1:36 pm on March 30, 2017 Permalink | Reply
    Tags: , , , , Draper, Solar research   

    From CfA: “Next Stop: A Trip Inside the Sun’s Atmosphere” 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    March 29, 2017
    Megan Watzke
    Harvard-Smithsonian Center for Astrophysics
    +1 617-496-7998
    mwatzke@cfa.harvard.edu

    Peter Edmonds
    Harvard-Smithsonian Center for Astrophysics
    +1 617-571-7279
    pedmonds@cfa.harvard.edu

    Dan Dent
    Draper Laboratory
    ddent@draper.com
    +1 617-258-2464

    1
    NASA’s Solar Probe Plus will enter the sun’s corona to understand space weather using a Faraday cup developed by the Smithsonian Astrophysical Observatory and Draper.
    NASA/Johns Hopkins University Applied Physics Laboratory

    Every so often the sun emits an explosive burst of charged particles that makes its way to Earth and often wreaks havoc on power grids, aircraft and satellite systems. When clouds of high-speed charged particles come racing off the sun, they can bathe spacecraft, astronauts and planetary surfaces in damaging radiation. Understanding why the sun occasionally emits these high-energy particles can help scientists predict space weather. Knowing when solar energetic particles may hit Earth can help people on the planet take precautions.

    Now, Draper and the Smithsonian Astrophysical Observatory (SAO) are addressing these challenges, and hoping to untangle these unsolved science mysteries, by developing sophisticated sensors for a new NASA mission. Launching in 2018, NASA’s Solar Probe Plus spacecraft, which is being designed and built by the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., will make 24 solar flybys over nearly seven years, setting a new record for the fastest moving man-made object as it zips 37.6 million kilometers closer to the sun than any spacecraft that has ever studied this star, and be exposed to temperatures exceeding 2500 degrees Fahrenheit.

    NASA’s Solar Probe Plus—the first mission that will fly into the sun’s upper atmosphere and “touch” the sun—will collect data on the mechanisms that heat the corona and accelerate the solar wind, a constant flow of charged particles from the sun. These are two processes with fundamental roles in the complex interconnected system linking the sun and near-Earth space—a system that can drive changes in our space weather and impact our satellites.

    To capture the velocity and direction of the positively-charged particles, Solar Probe Plus will be equipped with a Faraday cup, built by the Smithsonian Astrophysical Observatory, with technical support from Draper, and operated by SAO and the University of Michigan in Ann Arbor. The Faraday cup, which is capable of measuring the full force of supersonic solar particles and radiation, is one of only two instruments riding outside the protective sunshield of NASA’s Solar Probe Plus. The challenge will be to capture the data while operating at extreme temperatures on the fastest moving manmade spacecraft ever created—it will achieve a velocity of close to 200 km/sec—and do it with accuracy.

    For years, astronomers have studied the sun, but never from inside the sun’s atmosphere, according to Seamus Tuohy, Director of the Space Systems Program Office at Draper. “Such a mission would require a spacecraft and instrumentation capable of withstanding extremes of radiation, high velocity travel and the harsh solar condition—and that is the kind of program deeply familiar to Draper and the Smithsonian Astrophysical Observatory.”

    The investigation will specifically track the most abundant particles in the solar atmosphere and wind—electrons, protons and helium ions–“in addition to answering fundamental science questions, the intent is to better understand the risks space weather poses to the modern communication, aviation and energy systems we all rely on,” said Justin C. Kasper, principal investigator at the Smithsonian Astrophysical Observatory and University of Michigan Professor in Space Science. “Many of the systems we in the modern world rely on—our telecommunications, GPS, satellites and power grids—could be disrupted for an extended period of time if a large solar storm were to happen today. Solar Probe Plus will help us predict and manage the impact of space weather on society.”

    Draper

    At Draper, we believe exciting things happen when new capabilities are imagined and created. Whether formulating a concept and developing each component to achieve a field-ready prototype or combining existing technologies in new ways, Draper engineers apply multidisciplinary approaches that deliver new capabilities to customers. As a not-for-profit research and development company, Draper focuses on the design, development and deployment of advanced technological solutions for the world¹s most challenging and important problems. We provide engineering solutions directly to government, industry and academia; work on teams as prime contractor or subcontractor; and participate as a collaborator in consortia. We provide unbiased assessments of technology or systems designed or recommended by other organizations—custom designed, as well as commercial-off-the-shelf.

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    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 9:30 am on March 29, 2017 Permalink | Reply
    Tags: , , , , ESA Solar Orbiter, , Solar research   

    From ICL: “Imperial instrument ready to study the Sun” 

    Imperial College London
    Imperial College London

    29 March 2017
    Hayley Dunning
    Thomas Angus [Photographer]

    1
    Artist’s impression of the Solar Orbiter. Credit: ESA/AOES

    Imperial’s contribution to the Solar Orbiter mission, which will go closer to the Sun than anything so far, is ready to fly after extensive testing.

    Solar Orbiter is a European Space Agency mission carrying ten instruments to measure many different properties of the Sun and interplanetary space.

    Aboard the spacecraft, launching in early 2019, will be a magnetometer instrument built by a team from the Department of Physics at Imperial.

    The magnetometer will measure the Sun’s magnetic field in interplanetary space, carried by the solar wind. The solar wind is a stream of charged particles coming off the Sun that fills the Solar System, which the Sun’s magnetic field plays an important role in creating.

    Principal Investigator Professor Tim Horbury from the Department of Physics at Imperial said: “We live inside a bubble blown by the Sun in interstellar space. The Earth also has its own magnetic field, which creates a cavity in the solar bubble.

    2
    Professor Tim Horbury describes Solar Orbiter’s journey

    “The interaction between the solar wind and Earth’s magnetic field gives us the aurora – the Northern and Southern Lights – but when the solar wind is strong it can also cause problems for our technology, from power grids to satellites.”

    The Sun’s magnetic field is thought to be generated in a similar way to the Earth’s as it rotates, but it is much more dynamic. Every 11 years the polarity reverses, and this pattern is tied to the pattern of sunspots that appear on the Sun’s surface. Sunspots are associated extreme events called solar flares and ejections of the solar material that cause serious problems if they reach Earth.

    By orbiting the Sun and approaching it at a distance of only 50 million kilometres – inside the orbit of Mercury, the closest planet to the Sun – the Imperial team’s magnetometer will be able to get unprecedented information about how the Sun generates its magnetic field and how this plays a role in the solar wind and more extreme events.

    Sensitive subject

    The instrument is made up of two sensors hosted within metal domes; a black box containing electronics, a computer processor and a power supply; and cables to provide power and communications to the sensors.

    3
    Helen O’Brien describes the working of the sensors

    The magnetometer has to be extremely sensitive to detect the magnetic field from the Sun that will reach the spacecraft. Lead engineer Helen O’Brien from the Department of Physics said: “Our instrument is so sensitive, it could measure the magnetic field of an MRI machine from the other side of London.

    “This means, however, that we have to work hard to isolate it from the other instruments on the spacecraft. Metal objects and electrical circuits create small magnetic fields, so we have really strict requirements on the rest of the project – right down to the screws and the paint.”

    The magnetometer also has to survive some extreme conditions, including the intense vibration from the take-off, which will use a NASA Atlas V rocket. An earlier model of the instrument, which was put through rigorous tests designed to exceed the expected conditions, crumbled under the strain.

    4

    O’Brien said: “We mounted the sensors on a ceramic material that barely expands or contracts with temperature changes, so that their relative position to each other is kept stable during the extreme temperature swings the spacecraft will experience. However, this material is quite brittle, and it fell apart in the vibration test.”

    Thickening the material helped to solve the problem, and as a result of rigorous testing many tweaks and improvements have been made to the design. But now, the device is finished, and it is waiting in a clean room at Imperial before it gets mounted onto the spacecraft.

    In the meantime, the team are building a ‘flight spare’ – an identical device just in case something happens to the original before launch. When the instrument is mounted on the spacecraft, the team will be giving extremely precise instructions – down to the material the screwdriver is made out of, and making sure no tiny shavings of metal are left behind, which could disturb the measurements.

    Once all the instruments are mounted, the whole spacecraft will go through another barrage of tests, before being shipped to Cape Canaveral for launch in February 2019. It will then spend two years getting to the Sun, and another eight collecting data. Eventually, its solar panels will degrade and stop producing power but it will drift around the Sun forever.

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    Imperial College London

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

     
  • richardmitnick 12:51 pm on January 31, 2017 Permalink | Reply
    Tags: , , , , Gamma rays from solar storms, , Solar research   

    From Fermi: “NASA’s Fermi Sees Gamma Rays from ‘Hidden’ Solar Flares” 

    NASA Fermi Banner


    Fermi

    Jan. 30, 2017
    Francis Reddy
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    An international science team says NASA’s Fermi Gamma-ray Space Telescope has observed high-energy light from solar eruptions located on the far side of the sun, which should block direct light from these events. This apparent paradox is providing solar scientists with a unique tool for exploring how charged particles are accelerated to nearly the speed of light and move across the sun during solar flares.

    “Fermi is seeing gamma rays from the side of the sun we’re facing, but the emission is produced by streams of particles blasted out of solar flares on the far side of the sun,” said Nicola Omodei, a researcher at Stanford University in California. “These particles must travel some 300,000 miles within about five minutes of the eruption to produce this light.”

    Omodei presented the findings on Monday, Jan. 30, at the American Physical Society meeting in Washington, and a paper describing the results will be published online in The Astrophysical Journal on Jan. 31.


    Access mp4 video here .
    On three occasions, NASA’s Fermi Gamma-ray Space Telescope has detected gamma rays from solar storms on the far side of the sun, emission the Earth-orbiting satellite shouldn’t be able to detect. Particles accelerated by these eruptions somehow reach around to produce a gamma-ray glow on the side of the sun facing Earth and Fermi. Watch to learn more. Credits: NASA’s Goddard Space Flight Center/Scott Wiessinger, producer

    Fermi has doubled the number of these rare events, called behind-the-limb flares, since it began scanning the sky in 2008. Its Large Area Telescope (LAT) has captured gamma rays with energies reaching 3 billion electron volts, some 30 times greater than the most energetic light previously associated with these “hidden” flares.

    NASA/Fermi LAT
    NASA/Fermi LAT

    Thanks to NASA’s Solar Terrestrial Relations Observatory (STEREO) spacecraft, which were monitoring the solar far side when the eruptions occurred, the Fermi events mark the first time scientists have direct imaging of beyond-the-limb solar flares associated with high-energy gamma rays.

    NASA/STEREO spacecraft
    NASA/STEREO spacecraft

    3
    These solar flares were imaged in extreme ultraviolet light by NASA’s STEREO satellites, which at the time were viewing the side of the sun facing away from Earth. All three events launched fast coronal mass ejections (CMEs). Although NASA’s Fermi Gamma-ray Space Telescope couldn’t see the eruptions directly, it detected high-energy gamma rays from all of them. Scientists think particles accelerated by the CMEs rained onto the Earth-facing side of the sun and produced the gamma rays. The central image was returned by the STEREO A spacecraft, all others are from STEREO B.
    Credits: NASA/STEREO

    4
    Combined images from NASA’s Solar Dynamics Observatory (center) and the NASA/ESA Solar and Heliospheric Observatory (red and blue) show an impressive coronal mass ejection departing the far side of the sun on Sept. 1, 2014. This massive cloud raced away at about 5 million mph and likely accelerated particles that later produced gamma rays Fermi detected. Credits: NASA/SDO and NASA/ESA/SOHO

    NASA/SDO
    NASA/SDO

    ESA/NASA SOHO
    ESA/NASA SOHO

    “Observations by Fermi’s LAT continue to have a significant impact on the solar physics community in their own right, but the addition of STEREO observations provides extremely valuable information of how they mesh with the big picture of solar activity,” said Melissa Pesce-Rollins, a researcher at the National Institute of Nuclear Physics in Pisa, Italy, and a co-author of the paper.

    The hidden flares occurred Oct. 11, 2013, and Jan. 6 and Sept. 1, 2014. All three events were associated with fast coronal mass ejections (CMEs), where billion-ton clouds of solar plasma were launched into space. The CME from the most recent event was moving at nearly 5 million miles an hour as it left the sun. Researchers suspect particles accelerated at the leading edge of the CMEs were responsible for the gamma-ray emission.

    Large magnetic field structures can connect the acceleration site with distant part of the solar surface. Because charged particles must remain attached to magnetic field lines, the research team thinks particles accelerated at the CME traveled to the sun’s visible side along magnetic field lines connecting both locations. As the particles impacted the surface, they generated gamma-ray emission through a variety of processes. One prominent mechanism is thought to be proton collisions that result in a particle called a pion, which quickly decays into gamma rays.

    In its first eight years, Fermi has detected high-energy emission from more than 40 solar flares. More than half of these are ranked as moderate, or M class, events. In 2012, Fermi caught the highest-energy emission ever detected from the sun during a powerful X-class flare, from which the LAT detected high­energy gamma rays for more than 20 record-setting hours.

    NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

    For more information on Fermi, visit:

    https://www.nasa.gov/fermi

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    NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

     
  • richardmitnick 2:02 pm on December 16, 2016 Permalink | Reply
    Tags: , Solar research, Watch Out for Falling Plasma   

    From AAS NOVA: “Watch Out for Falling Plasma” 

    AASNOVA

    American Astronomical Society

    16 December 2016
    Susanna Kohler

    1
    The crosses in this SDO/AIA image mark the path taken by plasma that erupted from the Sun in a flare in June 2011 and then fell back down to the Sun’s surface. Such events can tell us about the local solar magnetic field and how it interacts with the plasma. [Petralia et al. 2016]

    Sometimes plasma emitted from the Sun doesn’t escape into space, but instead comes crashing back down to the solar surface. What can observations and models of this process tell us about how the plasma falls and the local conditions on the Sun?

    Fallback from a Flare

    On 7 June 2011, an M-class flare erupted from the solar surface. As the Solar Dynamics Observatory’s Atmospheric Imaging Assembly looked on, plasma fragments from the flare arced away from the Sun and then fell back to the surface.

    NASA/SDO
    NASA/SDO

    Some fragments fell back where the Sun’s magnetic field was weak, returning directly to the surface. But others fell within active regions, where they crashed into the Sun’s magnetic field lines, brightening the channels and funneling along them through the dense corona and back to the Sun’s surface.

    2
    The authors’ model of the falling blobs at several different times in their simulation. The blobs get disrupted when they encounter the field lines, and are then funneled along the channels to the solar surface. [Adapted from Petralia et al. 2016]

    This sort of flare and fall-back event is a common occurrence with the Sun, and SDO’s observations of the June 2011 event present an excellent opportunity to understand the process better. A team of scientists led by Antonino Petralia (University of Palermo, Italy and INAF-OAPA) modeled this event in an effort to learn more about how the falling plasma interacts with strong magnetic fields above the solar surface.

    Magnetic Fields as Guides

    Petralia and collaborators used three-dimensional magnetohydrodynamical modeling to attempt to reproduce the observations of this event. They simulated blobs of plasma as they fall back to the solar surface and interact with magnetic field lines over a range of different conditions.

    The team found that only simulations that assume a relatively strong magnetic field resulted in the blobs funneling along a channel to the Sun’s surface; with weaker fields the blobs to simply broke through the field lines.

    The observations were best reproduced by downfall channeled in a million-Kelvin coronal loop confined by a magnetic field of ~10–20 Gauss. In this scenario, a falling fragment is deviated from its path by the field and disrupted. It’s then channeled along the magnetic flux tube, driving a shock and heating in the tube ahead of it — which, the authors find, is the cause the observed brightening that occurs ahead of the actual plasma passage.

    Petralia and collaborators point out that this new mechanism for brightening downflows channeled by the magnetic field is applicable not only in our Sun, but also in young, accreting stars. Events like these can therefore work as probes of the ambient atmosphere of such stars, providing information about the local plasma density and magnetic field.

    Citation

    A. Petralia et al 2016 ApJ 832 2. doi:10.3847/0004-637X/832/1/2

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  • richardmitnick 9:37 pm on December 15, 2016 Permalink | Reply
    Tags: Solar research,   

    From Institute for Astronomy U Hawaii Manoa- “Giving the Sun a brake: Astronomers solve puzzle of slowing rotation” 

    U Hawaii

    University of Hawaii

    U Hawaii 2.2 meter telescope, Mauna Kea, Hawaii, USA
    U Hawaii 2.2 meter telescope, Mauna Kea, Hawaii, USA

    IFA at Manua Kea

    Dec 12, 2016
    Jeff Kuhn
    kuhn@ifa.hawaii.edu
    (808) 573-9517
    Astronomer, Institute for Astronomy

    Roy Gal
    roygal@hawaii.edu
    (808) 956-6235
    Associate Specialist, Institute for Astronomy

    1
    An image of the Sun taken with The Helioseismic and Magnetic Imager (HMI) on the Solar Dynamics Observatory spacecraft. NASA photo.

    NASA/SDO
    NASA/SDO

    Astronomers from the University of Hawaiʻi’s Institute for Astronomy (IfA), as well as Brazil and Stanford University, may have solved a long-standing solar mystery. Two decades ago, scientists discovered that the outer five percent of the Sun spins more slowly than the rest of its interior. Now, in a new study, to be published in the journal Physical Review Letters, IfA Maui scientists Ian Cunnyngham, Jeff Kuhn and Isabelle Scholl, together with Marcelo Emilio (Brazil) and Rock Bush (Stanford), describe the physical mechanism responsible for slowing the Sun’s outer layers.

    Said team leader Jeff Kuhn, “The Sun won’t stop spinning anytime soon, but we’ve discovered that the same solar radiation that heats the Earth is ‘braking’ the Sun because of Einstein’s Special Relativity, causing it to gradually slow down starting from its surface.”

    The Sun rotates on its axis at an average rate of about once per month but that rotation isn’t like, for example, the solid Earth or a spinning disk because the rate varies with solar latitude and distance from the center of the Sun.

    The team used several years of data from NASA’s Solar Dynamics Observatory and the Helioseismic and Magnetic Imager satellite to measure a sharp down-turn in the Sun’s rotation rate in its very outer 150km. Said Kuhn, “This is a gentle torque that is slowing it down, but over the Sun’s 5 billion year lifetime it has had a very noticeable influence on its outer 35,000km.” Their paper describes how this “photon-braking effect” should be at work in most stars.

    This change in rotation at the Sun’s surface affects the large-scale solar magnetic field and researchers are now trying to understand how the solar magnetism that extends out into the corona and finally into the Earth’s environment will be affected by this braking.

    The research will appear in the January issue of Physical Review Letters, and is available online at https://arxiv.org/abs/1612.00873.

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    System Overview

    The University of Hawai‘i System includes 10 campuses and dozens of educational, training and research centers across the Hawaiian Islands. As the public system of higher education in Hawai‘i, UH offers opportunities as unique and diverse as our Island home.

    The 10 UH campuses and educational centers on six Hawaiian Islands provide unique opportunities for both learning and recreation.

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  • richardmitnick 7:52 am on November 5, 2016 Permalink | Reply
    Tags: , , , Solar research   

    From Caltech: “Realistic Solar Corona Loops Simulated in Lab” 

    Caltech Logo
    Caltech

    11/04/2016

    Robert Perkins
    (626) 395-1862
    rperkins@caltech.edu

    1
    Side-by-side: A real coronal loop (left) compared to one simulated in Paul Bellan’s lab (right).
    Credit: Courtesy of P. Bellan/Caltech

    Caltech applied physicists have experimentally simulated the sun’s magnetic fields to create a realistic coronal loop in a lab.

    Coronal loops are arches of plasma that erupt from the surface of the sun following along magnetic field lines. Because plasma is an ionized gas—that is, a gas of free-flowing electrons and ions—it is an excellent conductor of electricity. As such, solar corona loops are guided and shaped by the sun’s magnetic field.

    The earth’s magnetic field acts as a shield that protects humans from the strong X-rays and energized particles emitted by the eruptions, but communications satellites orbit outside this shield field and therefore remain vulnerable. In March 1989, a particularly large flare unleashed a blast of charged particles that temporarily knocked out one of the National Oceanic and Atmospheric Administration’s geostationary operational environmental satellites that monitor the earth’s weather; caused a sensor problem on the space shuttle Discovery; and tripped circuit breakers on Hydro-Québec’s power grid, which blacked out the province of Quebec in Ontario, Canada, for nine hours.

    “This potential for causing havoc—which only increases the more humanity relies on satellites for communications, weather forecasting, and keeping track of resources—makes understanding how these solar events work critically important,” says Paul Bellan, professor of applied physics in the Division of Engineering and Applied Science.

    Although simulated coronal loops have been created in labs before, this latest attempt incorporated a magnetic strapping field that binds the loop to the sun’s surface. Think of a strapping field like the metal hoops on the outside of a wooden barrel. While the slats of the barrel are continually under pressure pushing outward, the metal hoops sit perpendicularly to the slats and hold the barrel together.

    The strength of this strapping field diminishes with distance from the sun. This means that when close to the solar surface, the loops are clamped down tightly by the strapping field but then can break loose and blast away if they rise to a certain altitude where the strapping field is weaker. These eruptions are known as solar flares and coronal mass ejections (CMEs).

    CMEs are rope-like discharges of hot plasma that accelerate away from the sun’s surface at speeds of more than a million miles per hour. These eruptions are capable of releasing energy equivalent to 1 billion megatons of TNT, making them potentially the most powerful explosions in the solar system. (CMEs are not to be confused with solar flares, which often occur as part of the same event. Solar flares are bursts of light and energy, while CMEs are blasts of particles embedded in a magnetic field.)

    The simulated loops and strapping fields provide new insight into how energy is stored in the solar corona and then released suddenly. Bellan worked with Caltech graduate student Bao Ha (MS ’10, PhD ’16) to create the strapping field and coronal loop. The results of their experiments were published in the journal Geophysical Research Letters on September 17, 2016.

    Bellan and his colleagues have been working on laboratory-scale simulations of solar corona phenomena for two decades. In the lab, the team generates ropes of plasma in a 1.5-meter-long vacuum chamber.

    “Studying coronal mass ejections is challenging, since humans do not know how and when the sun will erupt. But laboratory experiments permit the control of eruption parameters and enable the systematic explorations of eruption dynamics,” says Ha, lead author of the GRL paper. “While experiments with the same eruption parameters are easily reproducible, the loop dynamics vary depending on the configuration of the strapping magnetic field.”

    Simulating a strapping field with strength that fades over the relatively short length of the vacuum chamber proved difficult, Bellan says. In order to make it work, Ha and Bellan had to engineer electromagnetic coils that produce the strapping field inside the chamber itself.

    After more than three years of design, fabrication, and testing, Bellan and Ha were able to create a strapping field that peaks in strength about 10 centimeters away from where the plasma loop forms, then dies off a short distance farther down the vacuum chamber.

    The arrangement allows Bellan and Ha to watch the plasma loop slowly grow in size, then reach a critical point and fire off to the far end of the chamber.

    Next, Bellan plans to measure the magnetic field inside the erupting loop and also study the waves that are emitted when plasmas break apart.

    Their paper, titled Laboratory demonstration of slow rise to fast acceleration of arched magnetic flux ropes, is available online at http://onlinelibrary.wiley.com/doi/10.1002/2016GL069744/full. The research was supported by the National Science Foundation, the Air Force Office of Scientific Research, and the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences.

    See the full article here .

    Please help promote STEM in your local schools.

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    Caltech campus
    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

     
  • richardmitnick 7:28 am on October 18, 2016 Permalink | Reply
    Tags: , , , Solar research   

    From Goddard: “Wayward Field Lines Challenge Solar Radiation Models” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Oct. 17, 2016
    Lina Tran
    kathalina.k.tran@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    In addition to the constant emission of warmth and light, our sun sends out occasional bursts of solar radiation that propel high-energy particles toward Earth. These solar energetic particles, or SEPs, can impact astronauts or satellites. To fully understand these particles, scientists must look to their source: the bursts of solar radiation.

    But scientists aren’t exactly sure which of the two main features of solar eruptions –narrow solar flares or wide coronal mass ejections – causes the SEPs during different bursts. Scientists try to distinguish between the two possibilities by using observations, and computer models based on those observations, to map out where the particles could be found as they spread out and traveled away from the sun. NASA missions STEREO and SOHO collect the data upon which these models are built.

    NASA/STEREO spacecraft
    NASA/STEREO spacecraft

    ESA/NASA SOHO
    ESA/NASA SOHO

    Sometimes, these solar observatories saw SEPs on the opposite side of the sun than where the eruption took place. What kind of explosion on the sun could send the particles so far they ended up behind where they started?


    Access mp4 video here .
    This video compares the two models for particle distribution over the course of just three hours after an SEP event. The white line represents a magnetic field line, the general path that the SEPs follow. The line starts at an SEP event at the sun, and leads the particles in a spiral around the sun. The animation of the updated model, on the right, depicts a static field line, but as the SEPs travel farther in space, turbulent solar material causes wandering field lines. In turn, wandering field lines cause the particles to spread much more efficiently than the traditional model, on the left, predicted. Credits: NASA’s Goddard Space Flight Center/UCLan/Stanford/ULB/Joy Ng, producer

    Now a new model has been developed by an international team of scientists, led by the University of Central Lancashire and funded in part by NASA. The new model shows how particles could travel to the back of the sun no matter what type of event first propelled them. Previous models assumed the particles mainly follow the average of magnetic field lines in space on their way from the sun to Earth, and slowly spread across the average over time. The average field line forms a steady path following a distinct spiral because of the sun’s rotation. But the new model takes into consideration that magnetic fields lines can wander – a result of turbulence in solar material as it travels away from the sun.

    With this added information, models now show SEPs spiraling out much wider and farther than previous models predicted – explaining how SEPs find their way to even the far side of the sun. Understanding the nature of SEP distribution helps scientists as they continue to map out the origins of these high-energy particles. A paper published in Astronomy and Astrophysics on June 6, 2016, summarizes the research, a result of collaboration between the University of Central Lancashire, Université Libre de Bruxelles, University of Waikato and Stanford University.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    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
    NASA/Goddard Campus
    NASA image

     
  • richardmitnick 5:32 pm on May 23, 2016 Permalink | Reply
    Tags: , , , Solar research   

    From Goddard: “NASA: Solar Storms May Have Been Key to Life on Earth” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    May 23, 2016
    Karen C. Fox
    NASA’s Goddard Space Flight Center, Greenbelt, Md.
    karen.c.fox@nasa.gov

    Solar eruption 2012 by NASA's Solar Dynamic Observatory SDO
    Solar eruption 2012 by NASA’s Solar Dynamic Observatory SDO

    Our sun’s adolescence was stormy—and new evidence shows that these tempests may have been just the key to seeding life as we know it.

    Some 4 billion years ago, the sun shone with only about three-quarters the brightness we see today, but its surface roiled with giant eruptions spewing enormous amounts of solar material and radiation out into space. These powerful solar explosions may have provided the crucial energy needed to warm Earth, despite the sun’s faintness. The eruptions also may have furnished the energy needed to turn simple molecules into the complex molecules such as RNA and DNA that were necessary for life. The research was published* in Nature Geoscience on May 23, 2016, by a team of scientists from NASA.


    Access mp4 video here .

    Understanding what conditions were necessary for life on our planet helps us both trace the origins of life on Earth and guide the search for life on other planets. Until now, however, fully mapping Earth’s evolution has been hindered by the simple fact that the young sun wasn’t luminous enough to warm Earth.

    “Back then, Earth received only about 70 percent of the energy from the sun than it does today,” said Vladimir Airapetian, lead author of the paper and a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “That means Earth should have been an icy ball. Instead, geological evidence says it was a warm globe with liquid water. We call this the Faint Young Sun Paradox. Our new research shows that solar storms could have been central to warming Earth.”

    Scientists are able to piece together the history of the sun by searching for similar stars in our galaxy. By placing these sun-like stars in order according to their age, the stars appear as a functional timeline of how our own sun evolved. It is from this kind of data that scientists know the sun was fainter 4 billion years ago. Such studies also show that young stars frequently produce powerful flares – giant bursts of light and radiation — similar to the flares we see on our own sun today. Such flares are often accompanied by huge clouds of solar material, called coronal mass ejections, or CMEs, which erupt out into space.

    NASA’s Kepler mission found stars that resemble our sun about a few million years after its birth.

    NASA/Kepler Telescope
    NASA/Kepler Telescope

    The Kepler data showed many examples of what are called “superflares” – enormous explosions so rare today that we only experience them once every 100 years or so. Yet the Kepler data also show these youngsters producing as many as ten superflares a day.

    While our sun still produces flares and CMEs, they are not so frequent or intense.

    What’s more, Earth today has a strong magnetic field that helps keep the bulk of the energy from such space weather from reaching Earth.

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

    Space weather can, however, significantly disturb a magnetic bubble around our planet, the magnetosphere, a phenomenon referred to as geomagnetic storms that can affect radio communications and our satellites in space. It also creates auroras – most often in a narrow region near the poles where Earth’s magnetic fields bow down to touch the planet.

    Our young Earth, however, had a weaker magnetic field, with a much wider footprint near the poles.

    “Our calculations show that you would have regularly seen auroras all the way down in South Carolina,” says Airapetian. “And as the particles from the space weather traveled down the magnetic field lines, they would have slammed into abundant nitrogen molecules in the atmosphere. Changing the atmosphere’s chemistry turns out to have made all the difference for life on Earth.”

    The atmosphere of early Earth was also different than it is now: Molecular nitrogen – that is, two nitrogen atoms bound together into a molecule – made up 90 percent of the atmosphere, compared to only 78 percent today. As energetic particles slammed into these nitrogen molecules, the impact broke them up into individual nitrogen atoms. They, in turn, collided with carbon dioxide, separating those molecules into carbon monoxide and oxygen.

    The free-floating nitrogen and oxygen combined into nitrous oxide, which is a powerful greenhouse gas. When it comes to warming the atmosphere, nitrous oxide is some 300 times more powerful than carbon dioxide. The teams’ calculations show that if the early atmosphere housed less than one percent as much nitrous oxide as it did carbon dioxide, it would warm the planet enough for liquid water to exist.

    This newly discovered constant influx of solar particles to early Earth may have done more than just warm the atmosphere, it may also have provided the energy needed to make complex chemicals. In a planet scattered evenly with simple molecules, it takes a huge amount of incoming energy to create the complex molecules such as RNA and DNA that eventually seeded life.

    While enough energy appears to be hugely important for a growing planet, too much would also be an issue — a constant chain of solar eruptions producing showers of particle radiation can be quite detrimental. Such an onslaught of magnetic clouds can rip off a planet’s atmosphere if the magnetosphere is too weak. Understanding these kinds of balances help scientists determine what kinds of stars and what kinds of planets could be hospitable for life.

    “We want to gather all this information together, how close a planet is to the star, how energetic the star is, how strong the planet’s magnetosphere is in order to help search for habitable planets around stars near our own and throughout the galaxy,” said William Danchi, principal investigator of the project at Goddard and a co-author on the paper. “This work includes scientists from many fields — those who study the sun, the stars, the planets, chemistry and biology. Working together we can create a robust description of what the early days of our home planet looked like – and where life might exist elsewhere.”

    For more information about the Kepler mission, visit:

    http://www.nasa.gov/kepler

    *Science paper:
    Prebiotic chemistry and atmospheric warming of early Earth by an active young Sun

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 5:04 pm on March 30, 2016 Permalink | Reply
    Tags: , , , Solar research   

    From Eos: “Toward an Understanding of Earth-Affecting Solar Eruptions” 

    Eos news bloc

    Eos

    3.30.16
    Yuming Wang
    ymwang@ustc.edu.cn

    Solar eruption 2012 by NASA's Solar Dynamic Observatory SDO
    Solar eruption 2012 by NASA’s Solar Dynamic Observatory SDO

    Solar eruptions are frequently occurring phenomena on the Sun where large-scale magnetized bubbles and large amounts of electromagnetic radiation and energetic particles spread into space. The radiation and masses that solar eruptions release have potential impacts on Earth so it’s been an important area of study in the space physics and space weather communities. Flares are one kind of solar eruption and have been studied for hundreds of years; before the 1990s, they were believed to be the major driving sources of the disturbances in space. As observational technology improved, scientists began to realize that another kind of solar eruption—coronal mass ejections (CMEs), which accompany flares—play a more important role in producing the disturbances that could negatively affect Earth.

    One of the most important motivations to study solar eruptions is their application to space weather forecasting. Flares are a relatively small-scale phenomenon on the Sun and affect the Earth mostly through electromagnetic emissions and energetic particles. Flares exhibit fairly predictable behavior, so it’s relatively easy to anticipate the effect they are going to have on the Earth and our systems: their electromagnetic radiations travel radially at light speed and energetic particles propagate roughly along the spiral interplanetary magnetic field lines at a relativistic speed and don’t spread out too much in space and time. However, CMEs are harder to predict. They affect the Earth through transient magnetized bubbles and associated shocks and energetic particles. They can travel with a wide range of speed from 100 to more than 3000 kilometers per second. Such a wide spectrum could appear in many other properties of CMEs, like strength, size, orientation and propagation direction. Moreover, during their journey through space, these properties can be altered by ambient solar wind. Thus, the effect they have on Earth and our systems becomes much more intricate to be forecast than that of flares.

    There are lots of questions to be answered in predicting the significance of the effects that CMEs could have on Earth. The primary questions, in logical order, are: Will the CME hit the Earth? When will the CME hit the Earth? Will it trigger a geomagnetic storm and what will the size of the storm be? Will it initiate a solar energetic particle (SEP) event, manifesting a significant enhancement of the flux of energetic particles, and how strong might that SEP event be?

    Even for the first question, the answer is not straightforward. A good example is the fast CME on 15 March 2015 which produced so far the largest geomagnetic storms in the 24th solar cycle. However, the Space Weather Prediction Center initially forecasted it as a much smaller event because the CME seemed not to have been propagating toward the Earth. This surprising event has attracted the attention of space physics and space weather communities. Some analyses suggest that the interaction of the CME with the corona and ambient solar wind increased the chance of the CME to produce the major geomagnetic storm [Kataoka et al., 2015 and other works, e.g., by Wood B. E. et al. and Wang Y. et al., both under consideration by a AGU journal].

    As one of four projects under the SCOSTEP (Scientific Committee on Solar-Terrestrial Physics) program Variability of the Sun and Its Terrestrial Impact (VarSITI), International Study of Earth-affecting Solar Transients (ISEST) is devoted to solving these puzzles. The Solar TErrestrial RElations Observatory (STEREO) mission launched in 2006 largely inspired the relevant research with its unprecedented imaging data of the interplanetary medium.

    NASA/STEREO spacecraft
    NASA/STEREO spacecraft

    The upcoming space missions Solar Orbiter and Solar Probe Plus, which are scheduled to be launched in 2017 and 2018 respectively, will take a much closer look at the Sun and sample the solar wind plasma.

    ESA/Solar Orbiter
    ESA/Solar Orbiter

    NASA/SPP Solar Probe Plus
    NASA/SPP Solar Probe Plus

    These new and exciting data will undoubtedly advance our understanding in the Earth-affecting solar eruptions in the near future.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
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