Tagged: Solar research Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 7:33 am on September 10, 2019 Permalink | Reply
    Tags: Astronomers use the sun’s composition as a reference for the universe., , , , , , , Solar research, Standard Solar Model, Two-photon opacity   

    From Sandia Lab: “Sandia experiments at temperature of sun offer solutions to solar model problems” 

    From Sandia Lab

    September 10, 2019
    Neal Singer
    nsinger@sandia.gov
    505-845-7078

    Sandia’s Z machine helps reconcile sun’s energy and composition

    Sandia Z machine

    Experimenting at 4.1 million degrees Fahrenheit, physicists at Sandia National Laboratories’ Z machine have found that an astronomical model — used for 40 years to predict the sun’s behavior as well as the life and death of stars — underestimates the energy blockage caused by free-floating iron atoms, a major player in those processes.

    2
    Sandia National Laboratories researcher Taisuke Nagayama in a quiet moment at Sandia’s Z machine, which reaches the temperature of stars. (Photograph by Randy Montoya).

    The blockage effect, called opacity, is an element’s natural resistance to energy passing through it, similar to an opaque window’s resistance to the passage of light.

    “By observing real-world discrepancies between theory and our experiments at Z, we were able to identify weaknesses in opacity figures inserted into solar models,” said Taisuke Nagayama, lead author on the Sandia groups’ latest publication in Physical Review Letters.

    The good news is that that Sandia’s experimental opacity measurements can help bloodlessly resolve a major discrepancy in how the widely used Standard Solar Model uses the composition of the sun to predict the behavior of stars.

    Until 2005, the SSM’s multiplication of the amount of each element present by its opacity accounted for the observed temperature structure of the sun. But new astrophysical observations and more sophisticated physics then led astronomers to revise their estimates of the sun’s composition. Unfortunately, these new estimates, inserted into the model and multiplied by their opacities, did not account for the sun’s temperature. There were three possibilities: either the new composition observations were inaccurate, or the venerated SSM was wrong, or the theoretically derived opacities of elements were incorrect.

    Experiments at the sun’s temperature provide answers

    The best resolution clearly would come from experiments performed at the same temperatures as those found in the sun’s interior.

    More than a decade ago, Sandia researchers began taking pieces of iron, each smaller than a dime, and inserting them into the target area of Z. When Z fired, the extreme heat changed the solid into plasma (a gas) as it exists in the sun, but only for nanoseconds. That was long enough, however, for researchers to send an energy wave through each sample and measure how much got through. The idea was to create, for the first time, laboratory-derived measures of the opacity of iron at the temperature of the sun to learn whether it agreed with the theoretical figures used in Standard Solar Model calculations.

    Increasing the opacity of iron to the extent demonstrated by Z in multiple independent experiments removed about half the discrepancy between computed and actual solar temperature, Nagayama said.

    3
    The top graph in red shows greater opacity of iron as determined experimentally by Sandia National Laboratories’ Z machine. The lower graph shows the earlier theoretical calculation. (Graphic provided by Sandia National Laboratories researcher Taisuke Nagayama).

    “Astronomers are happy with us because we’re saying it’s the opacity figures that may be wrong,” said paper author and Sandia researcher Jim Bailey. “Then they don’t have to come up with a new model and redo all their calculations using the sun as a benchmark for predicting the evolution of stars.”

    That’s because astronomers use the sun’s composition as a reference for the universe.

    “Decreasing the oxygen amount in the sun by 50% is equivalent to halving the amount of water (H2O) in the universe,” said Bailey. “There are many exoplanets orbiting around sun-like stars; revising the understanding of our sun would also have significant impact on understanding those exoplanets.

    “The astronomers liked the opacity supposition the best, and that’s what we’re finding so far.”

    A metallic surprise

    On the same test, Sandia also measured the opacities of chromium and nickel under the same conditions used on iron. The idea was to use those elements — respectively smaller and larger than iron, but adjacent to iron in the periodic table — as though iron were being tested closer and farther from the sun’s core. Surprisingly, those elements produced experimental opacity results basically in accord with model predictions at some photon energies. Still, they differed from opacity predictions at particular wavelengths — further grist for model revision.

    “Our work over the last five years has been focused on resolving the discrepancies,” said Nagayama. “And yet the new results mean new science may be necessary to account for them.”

    To explain new experimental results, physicists are examining new models. One, called two-photon opacity [High Energy Density Physics], explores the idea that an element may absorb two photons at a time instead of the one thought standard.

    “If this multi-photon absorption is considered in the model, it would enhance the calculated iron opacity and may resolve the discrepancy,” he said.

    If correct, the new physics model must calculate the opacity increase only for iron, since model and data already agree for chromium and nickel.

    Other experimental limitations include the fact that little is known about the structure of the sun inside particular distances from the sun’s center.

    “Is the discrepancy worse if you go even deeper in the sun?” Nagayama asked. “We don’t know. It all depends on what’s causing the discrepancy. We may find that the discrepancy is even worse in the solar core, or the problem may be isolated to the region around 0.7 solar radii, the distance which matches the energies at which these experiments were performed.”

    Answering those questions should lead to a more accurate model, he said.

    “Experiments of hot dense plasma are challenging enough that we should not rule out the possibility of error,” Nagayama said. “And the science impact is enormous — this obligates us to continue examining the experiment’s validity.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Sandia Campus
    Sandia National Laboratory

    Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.
    i1
    i2
    i3

     
  • richardmitnick 8:01 am on September 6, 2019 Permalink | Reply
    Tags: "Forecasting Solar Storms in Real Time", , CME Scoreboard, , , Solar research,   

    From Eos: “Forecasting Solar Storms in Real Time” 

    From AGU
    Eos news bloc

    From Eos

    30 August 2019
    Jenessa Duncombe

    Predicting when solar storms will hit Earth remains a tricky business. To help, scientists can now submit their forecasts of coronal mass ejections online as they unfold in real time.

    1
    A coronal mass ejection (CME) blasts off from the Sun in these coronagraphs captured on 27 February 2000 by the Solar and Heliospheric Observatory spacecraft. Credit: SOHO ESA & NASA


    ESA/NASA SOHO

    The Sun routinely ejects clouds of gas and sends them hurtling through space at several thousand kilometers per hour. At least a few dozen times a year, those clouds head straight for Earth.

    These natural events, called coronal mass ejections (CMEs), crop up when the Sun’s magnetic field becomes tangled and, in righting itself, releases a swarm of charged particles called superheated plasma. Sent at just the right angle toward Earth, these plasma clouds can wreak havoc on our electrical grids, satellites, and oil and gas pipelines.

    Quebec, Canada, for instance, experienced a blackout related to a solar storm on a winter night in 1989. The province went black after a solar storm sent an electric charge into the ground that shorted the electrical power grid. The outage lasted 12 hours, stranding people in elevators and pedestrian tunnels and closing down airports, schools, and businesses.

    Solar storms can threaten our communication and navigation infrastructure. In the past, solar storms interrupted telegraph messages, and future storms could threaten our cellphones, GPS capabilities, and spacecraft.

    With the right kind of warning, utility operators, space crews, and communications personnel can prepare and steer clear of certain activities during solar storms. But once a CME event is spotted leaving the Sun, our best models struggle to forecast when exactly it will arrive.

    To improve forecasts, a group of scientists is taking a community approach: What if researchers working on CME models around the world could post their forecasts publicly, in real time, before the CME reaches Earth?

    The CME Scoreboard, run by the Community Coordinated Modeling Center at NASA Goddard Space Flight Center, does just that. The online portal with 159 registered users acts as a live feed of CME predictions heading for Earth. The portal gives scientists a simple way to compare forecasts, and the log of past predictions presents a valuable data set to assess forecasters’ accuracy and precision.

    Keeping Score

    The AGU Grand Challenges Centennial Collection features the major questions faced by science today. Editors of Space Weather identified CME predictions as one of them, calling the ability to provide them “essential for our society [Space Weather].”

    CME forecasting still lags behind our capabilities to forecast weather systems here on Earth, and the paper highlights several reasons why. Leila Mays, coauthor on the paper and science lead for the CME Scoreboard at NASA Goddard Space Flight Center, said that CME forecasts are lacking in two key areas: Measurements of solar activity are sparse, and the exact physical details driving the Sun are still unclear.

    Despite the need for improvement, people on Earth still rely on CME forecasts, and scientists have myriad ways to supply them. The National Oceanic and Atmospheric Administration and the United Kingdom’s Met Office both release publicly available CME predictions, and individual research groups build their models from scratch. Forecasting models range from data-driven empirical models to physics-based, equation-driven models.

    The models operate independently, perhaps using unique parameters or data inputs, but they all strive for a shared goal: to determine when a CME, or CME’s shock wave, will impact Earth.

    The CME Scoreboard serves as a repository for a wide range of these models. Mays said that scientists tracking solar activity will notice when a CME event explodes from the surface of the Sun, setting down a ticking clock for when the plasma will hit Earth (or miss it altogether). This sets off a flurry of activity, with scientists running their models with parameters from the most recent eruption, including the plasma’s speed, direction, and size. With the numbers crunched, they post their best guess and wait to see what unfolds.

    Ground Truth

    Since the CME Scoreboard’s inception in 2013, scientists have posted 814 arrival time predictions. Some predictions narrowly miss the mark, skirting the real arrival time of the CME by a mere hour or two. But others are days away, trailing the arrival by 30 or more hours.

    Mays said that the forecasts come from over a hundred users and represent 26 unique prediction methods. She said that the interest in the portal has been strong, which she’s not surprised about. The scoreboard merely gives a platform for ad hoc discussions that researchers were already having, spread across listservs and email chains whenever a new CME would appear.

    Pete Riley, a senior research scientist at Predictive Science Inc., knew of the scoreboard but had never contributed. Looking at years of forecasts on the website, he decided to analyze the accuracy and precision of past predictions.

    “I felt like having knowledge in the field but not having a horse in the race, so to speak, I’d be able to do a fairly independent evaluation,” Riley told Eos.

    His study, published in Space Weather in 2018, is the first analysis of the scoreboard data. Riley and his collaborators compared the difference between the projected arrival times and the actual reported times for 32 models. The analysis showed that the forecasts, on average, predicted the CME arrival with a 10-hour error, and they had a standard deviation of 20 hours. Several models performed the best, he said, but only moderately so, and the few that submitted regularly over the 6 years of data analyzed didn’t seem to be improving their forecasts.

    The paper “serves as kind of a ground truth for where we are at currently,” Riley said, as well as laying the foundation for future analysis. Riley made the code accessible so that future forecasts can be tested against the group. Mays said that in the future, the scoreboard may use the information to create a list of automatically updating metrics.

    Although more work lies ahead, Riley said that the future looks bright for more accurate predictions. He points to new space missions that will help fill in blind spots, including NASA’s Parker Solar Probe and nanosatellites called CubeSats that individual research groups deploy.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker

    “Space weather is becoming ever more important because as a society, we are so reliant on technology now,” Riley said. With the additional data, he said, “I think it’s promising that in the future we will be able to make predictions more accurate.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    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.

     
  • richardmitnick 1:12 pm on August 24, 2019 Permalink | Reply
    Tags: "NASA’s BITSE Solar Scope Is Ready for Balloon Flight Over New Mexico", , , , , KASI-Korea Astronomy and Space Science Institute, , Solar research   

    From NASA Goddard Space Flight Center: “NASA’s BITSE Solar Scope Is Ready for Balloon Flight Over New Mexico” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Aug. 23, 2019
    Lina Tran
    lina.tran@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    NASA and the Korea Astronomy and Space Science Institute, or KASI, are getting ready to test a new way to see the Sun, high over the New Mexico desert.

    A balloon — large enough to hug a football field — is scheduled to take flight no earlier than Aug. 26, 2019, carrying beneath it a solar scope called BITSE. BITSE is a coronagraph, a kind of telescope that blocks the Sun’s bright face in order to reveal its dimmer atmosphere, called the corona. Short for Balloon-borne Investigation of Temperature and Speed of Electrons in the corona, BITSE seeks to explain how the Sun spits out the solar wind.

    The solar wind is the stream of charged particles that constantly blows from the Sun’s outer atmosphere, washing over the entire solar system. While scientists generally know where it forms, exactly how it does so remains a mystery. But unlocking the nature of the solar wind is key to predicting how solar eruptions travel. The solar wind is a bit like a water slide: Its flow determines how a solar storm barrels through space. Sometimes, the storms crash into Earth’s magnetic field, sparking disturbances that can interfere with satellites and everyday communications systems like radio or GPS.

    A collaboration between NASA and KASI, BITSE demonstrates a new way to study the solar wind. While standard coronagraphs capture the corona’s density, BITSE also measures the temperature and speed of electrons in the solar wind to help understand the powerful forces that accelerate them to speeds of 1 million miles per hour. BITSE’s balloon flight is a key step in the testing and development of this instrument, and will help the team of scientists and engineers fine-tune their technology for future spaceflight.

    “This is a coronagraph capable of measuring these three properties, all of which you need to understand how the solar wind is formed and accelerated,” said Nat Gopalswamy, BITSE principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. By improving coronagraphs, BITSE furthers our understanding of the corona itself, the driving force behind the solar stuff that fills the space around Earth — ultimately improving our ability to forecast weather in space.


    NASA and KASI’s BITSE will fly up to the edge of the atmosphere from NASA’s Columbia Scientific Balloon Facility’s field site in Fort Sumner, New Mexico. BITSE seeks to explain how the Sun spits out the solar wind.
    Credits: NASA’s Goddard Space Flight Center/Joy Ng

    Flying to the edge of the atmosphere

    Before launch, in the wee hours of morning, technicians from NASA’s Columbia Scientific Balloon Facility’s field site in Fort Sumner, New Mexico, will ready the balloon for flight, partially filling the large plastic envelope with helium. The balloon is made of polyethylene — the same material grocery bags are made of — and is about as thick as a plastic sandwich bag, but much stronger. As the balloon rises higher above the surface and atmosphere pressure drops, the gas in the balloon expands and it swells.

    BITSE will meander upwards until it is some 22 miles above the ground. There, it will coast, taking pictures of the Sun’s seething hot atmosphere. By the end of the day, it will have collected as much as 64 gigabytes — 40 feature-length movies’ worth — of data.

    BITSE’s journey to the sky began with an eclipse. Coronagraphs work by mimicking eclipses; like the Moon, a metal disk — called an occulter — blocks the Sun, bringing the corona into the spotlight. During the Aug. 21, 2017, total solar eclipse, Gopalswamy and his team tested key parts of the instrument in Madras, Oregon. In just two minutes of totality, they took 50 images — and demonstrated the challenges and advantages of utilizing their instrument’s particular technique.

    Now, the team is no longer limited to hurried research in the Moon’s shadow. A balloon will take their instrument to the edge of the atmosphere, where it will fly for at least six hours. Balloons offer a low-cost way to access this region, allowing scientists to make measurements and perform tests they can’t from the ground. There, BITSE can collect its images with much less background light than from the ground, which interferes with observations of the dim corona.

    A new type of coronagraph

    2
    Team member Nelson Reginald examines the BITSE instrument in the lab where it was built, at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. BITSE is a coronagraph, a kind of telescope that blocks the Sun’s bright face in order to reveal its dimmer atmosphere. Credits: NASA’s Goddard Space Flight Center/Joy Ng

    BITSE combines several important technologies. First, the instrument is constructed with a single occulting stage. Then, there’s a special camera that captures polarized light — light waves that bob in certain directions. Scientists use these photos to map out electron density, or how many electrons are in the corona and where.

    Typical coronagraphs use a wheel that cycles through polarizer filters — each oriented to different angles — and combine the images to get the polarized light. BITSE’s polarization camera analyzes the observations pixel by pixel, making the process more reliable by reducing the number of moving parts.

    “We glued the entire sheet of micro-polarizers on top of the camera detector, so we don’t need the polarization wheel,” said Qian Gong, BITSE lead optics engineer at Goddard.

    BITSE also has a filter wheel, which blocks out all the corona’s light except for four specific wavelengths. The ratios of these different wavelengths provide scientists with the temperature and speed of electrons in the corona — measurements they can’t obtain from the ground, even during an eclipse. By focusing on a previously unstudied slice of the corona that is key to solar wind formation, the scientists hope to gather new clues to its origins. One day, a version of BITSE could make these measurements from space, extending their observation time from hours to months.

    More than 22 miles above the surface, BITSE will drift high above the realm of birds, airplanes, weather, and the blue sky itself. The altitude presents unique challenges, Gong said. Certain design elements are specific to balloon flight, like BITSE’s temperature-sensitive optics. An onboard thermal system will ensure BITSE doesn’t get too cold during its ascent. Even the glue they used on the polarization filters was carefully selected both to provide good adhesive and withstand the expected temperatures. A shift of just a few microns — an average human hair is 75 microns across — in response to the chilly upper atmosphere could impact their data, she explained, since each pixel is 7.5 microns wide.

    At such high altitudes, the sky is dimmer; where the atmosphere is thin, there are few air particles to scatter light. Compared to the ground, these are much better conditions for a coronagraph. Still, the edge of the atmosphere is brighter than space.

    “The sky brightness fundamentally limits what we can see, and drives our need to go to the next step: observations from space,” Goddard solar scientist Jeff Newmark said. Together, Gopalswamy and Newmark are leading the team sending BITSE to the sky, one step closer to space, where there’s no interfering background light.

    A true collaborative mission, BITSE features extensive contributions from both NASA and KASI. NASA provided the main optical, mechanical, pointing, communications, and gondola assemblies, as well as overall management and launch of the mission, while KASI provided the filter wheel, instrument computer and camera system, among other contributions.

    Lofty goals

    At the end of BITSE’s flight, technicians at the Fort Sumner field site will send termination commands, kicking off a sequence that separates the instrument and balloon, deploys the instrument’s parachute, and punctures the balloon. An airplane circling overhead will keep watch over the balloon’s final moments, and relay BITSE’s location. Hours later, far from where it started, the coronagraph will parachute to the ground. A crew will drive into the desert to recover both the balloon and BITSE at the end of the day.

    Data from BITSE’s flight will be useful for the models that scientists use to predict space weather. But the team will be looking to the flight to validate BITSE’s design and performance in a near-space environment. From their field campaign observing the Aug. 2017 solar eclipse to this year’s balloon flight and eventually, spaceflight, the team has continued to set their sights ever higher.

    Related:

    Studying the Sun’s Atmosphere with the Total Solar Eclipse of 2017
    NASA Team to Fly First-Ever Coronagraph Capable of Determining the Formation of the Solar Wind

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    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

     
  • richardmitnick 3:19 pm on August 8, 2019 Permalink | Reply
    Tags: "NASA’s MMS Finds First Interplanetary Shock", , , , , , Interplanetary shocks are a type of collisionless shock — ones where particles transfer energy through electromagnetic fields instead of directly bouncing into one another., Interplanetary shocks start at the Sun which continually releases streams of charged particles called the solar wind., MMS consists of four identical spacecraft which fly in a tight formation that allows for the 3D mapping of space., NASA MMS Mission, Solar research   

    From NASA: “NASA’s MMS Finds First Interplanetary Shock” 

    NASA image
    From NASA

    Aug. 8, 2019
    Mara Johnson-Groh
    mara.johnson-groh@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    The Magnetospheric Multiscale mission — MMS — has spent the past four years using high-resolution instruments to see what no other spacecraft can. Recently, MMS made the first high-resolution measurements of an interplanetary shock.

    NASA MMS satellites in space. Credit: NASA

    These shocks, made of particles and electromagnetic waves, are launched by the Sun. They provide ideal test beds for learning about larger universal phenomena, but measuring interplanetary shocks requires being at the right place at the right time. Here is how the MMS spacecraft were able to do just that.

    What’s in a Shock?

    Interplanetary shocks are a type of collisionless shock — ones where particles transfer energy through electromagnetic fields instead of directly bouncing into one another. These collisionless shocks are a phenomenon found throughout the universe, including in supernovae, black holes and distant stars. MMS studies collisionless shocks around Earth to gain a greater understanding of shocks across the universe.

    Interplanetary shocks start at the Sun, which continually releases streams of charged particles called the solar wind.

    The solar wind typically comes in two types — slow and fast. When a fast stream of solar wind overtakes a slower stream, it creates a shock wave, just like a boat moving through a river creates a wave. The wave then spreads out across the solar system. On Jan. 8, 2018, MMS was in just the right spot to see one interplanetary shock as it rolled by.

    Catching the Shock

    MMS was able to measure the shock thanks to its unprecedentedly fast and high-resolution instruments. One of the instruments aboard MMS is the Fast Plasma Investigation. This suite of instruments can measure ions and electrons around the spacecraft at up to 6 times per second. Since the speeding shock waves can pass the spacecraft in just half a second, this high-speed sampling is essential to catching the shock.

    Looking at the data from Jan. 8, the scientists noticed a clump of ions from the solar wind. Shortly after, they saw a second clump of ions, created by ions already in the area that had bounced off the shock as it passed by. Analyzing this second population, the scientists found evidence to support a theory of energy transfer first posed in the 1980s.

    MMS consists of four identical spacecraft, which fly in a tight formation that allows for the 3D mapping of space. Since the four MMS spacecraft were separated by only 12 miles at the time of the shock (not hundreds of kilometers as previous spacecraft had been), the scientists could also see small-scale irregular patterns in the shock. The event and results were recently published in the Journal of Geophysical Research.

    3
    Data from the Fast Plasma Investigation aboard MMS shows the shock and reflected ions as they washed over MMS. The colors represent the amount of ions seen with warmer colors indicating higher numbers of ions. The reflected ions (yellow band that appears just above the middle of the figure) show up midway through the animation, and can be seen increasing in intensity (warmer colors) as they pass MMS, shown as a white dot. Credits: Ian Cohen

    Going Back for More

    Due to timing of the orbit and instruments, MMS is only in place to see interplanetary shocks about once a week, but the scientists are confident that they’ll find more. Particularly now, after seeing a strong interplanetary shock, MMS scientists are hoping to be able to spot weaker ones that are much rarer and less well understood. Finding a weaker event could help open up a new regime of shock physics.

    Related Link

    Learn more about NASA’s MMS Mission

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 5:20 pm on July 29, 2019 Permalink | Reply
    Tags: “We’re not re-creating the sun because that’s impossible” says plasma physicist Ethan Peterson of the University of Wisconsin–Madison. “But we’re re-creating some of the fundamental phys, , NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker, Parker spiral named after solar physicist Eugene Parker who predicted the existence of the solar wind in 1958., , , , Solar research, The magnet in the center of the ball mimics the sun’s magnetic field and carefully applied electric currents send the plasma spinning and a wind streaming., The sun spews a constant stream of charged particles-called the solar wind out into space - though scientists aren’t sure exactly how., The team used a 3-meter-wide aluminum vacuum chamber called the Big Red Ball heated to 100000° Celsius at the Wisconsin Plasma Physics Laboratory.,   

    From University of Wisconsin Madison via Science News: “In a first, physicists re-created the sun’s spiraling solar wind in a lab” 

    U Wisconsin

    From University of Wisconsin Madison

    via

    Science News

    July 29, 2019
    Lisa Grossman

    Some of the sun’s fundamental physics have been re-created with plasma inside a vacuum chamber.

    1
    SUN IN A BALL This view shows the inside of the Big Red Ball, a 3-meter-wide aluminum sphere at the University of Wisconsin–Madison that can mimic properties of the sun. Carefully applied magnets and electric currents make the plasma spin and send out streams of charged particles, like the solar wind. Univ. of Wisconsin-Madison

    Physicists have created mini gusts of solar wind in the lab, with hopes that the charged particle streams can help to resolve some mysteries about our nearest star [Nature Physics].

    “We’re not re-creating the sun, because that’s impossible,” says plasma physicist Ethan Peterson of the University of Wisconsin–Madison, who reports the new work July 29 in Nature Physics. “But we’re re-creating some of the fundamental physics that happens near the sun.”

    The sun spews a constant stream of charged particles, called the solar wind, out into space — though scientists aren’t sure exactly how (SN Online: 8/18/17). As the sun rotates, its magnetic field twists the wind into a helical shape called the Parker spiral, named after solar physicist Eugene Parker, who predicted the existence of the solar wind in 1958.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker

    NASA last year launched its Parker Solar Probe to directly investigate the source of the solar wind (SN: 7/21/18, p. 12). But Peterson and colleagues found a way to mimic the Parker spiral much closer to home.

    The team used a 3-meter-wide aluminum vacuum chamber called the Big Red Ball at the Wisconsin Plasma Physics Laboratory to confine a ball of plasma heated to 100,000° Celsius. A magnet in the center of the ball mimics the sun’s magnetic field, and carefully applied electric currents send the plasma spinning and a wind streaming.

    There are some unavoidable differences between the Big Red Ball and the sun, including size, gravity and temperature. Even so, the wind organized itself into a clear Parker spiral, as expected. The wind also occasionally ejected little blobs of plasma, each about 10 centimeters across. The sun ejects similar blobs, called plasmoids, but no one is sure why. The Big Red Ball could help provide an answer, Peterson says.


    BALLERINA SKIRT The Parker spiral, which has also been described as a “ballerina skirt,” is the shape that the solar wind takes on as the sun rotates, twisting the wind into a helix as seen in a NASA simulation. Scientists mimicked this spiral in plasma in the lab. This video shows a smaller Parker spiral appearing in a ball of hot, spinning plasma inside a vacuum chamber. The bright spiraling structures follow the plasma’s magnetic field.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
  • richardmitnick 9:09 am on June 22, 2019 Permalink | Reply
    Tags: , PUNCH mission, Solar research, , TRACERS mission   

    From NASA: “NASA Selects Missions to Study Our Sun, Its Effects on Space Weather” 

    NASA image
    From NASA

    June 20, 2019

    Grey Hautaluoma
    Headquarters, Washington
    202-358-0668
    grey.hautaluoma-1@nasa.gov

    Karen Fox
    Headquarters, Washington
    301-286-6284
    karen.c.fox@nasa.gov

    1
    A constant outflow of solar material streams out from the Sun, depicted here in an artist’s rendering. On June 20, 2019, NASA selected two new missions – the Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission and Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) – to study the origins of this solar wind and how it affects Earth. Together, the missions support NASA’s mandate to protect astronauts and technology in space from such radiation. Credits: NASA

    NASA has selected two new missions to advance our understanding of the Sun and its dynamic effects on space. One of the selected missions will study how the Sun drives particles and energy into the solar system and a second will study Earth’s response.

    The Sun generates a vast outpouring of solar particles known as the solar wind, which can create a dynamic system of radiation in space called space weather. Near Earth, where such particles interact with our planet’s magnetic field, the space weather system can lead to profound impacts on human interests, such as astronauts’ safety, radio communications, GPS signals, and utility grids on the ground. The more we understand what drives space weather and its interaction with the Earth and lunar systems, the more we can mitigate its effects – including safeguarding astronauts and technology crucial to NASA’s Artemis program to the Moon.

    2
    NASA’s Artemis spacecraft. The Planetary Society

    “We carefully selected these two missions not only because of the high-class science they can do in their own right, but because they will work well together with the other heliophysics spacecraft advancing NASA’s mission to protect astronauts, space technology and life down here on Earth,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. “These missions will do big science, but they’re also special because they come in small packages, which means that we can launch them together and get more research for the price of a single launch.”

    PUNCH

    The Polarimeter to Unify the Corona and Heliosphere, or PUNCH, mission will focus directly on the Sun’s outer atmosphere, the corona, and how it generates the solar wind.

    3
    PUNCH four satellites

    Composed of four suitcase-sized satellites, PUNCH will image and track the solar wind as it leaves the Sun. The spacecraft also will track coronal mass ejections – large eruptions of solar material that can drive large space weather events near Earth – to better understand their evolution and develop new techniques for predicting such eruptions.

    These observations will enhance national and international research by other NASA missions such as Parker Solar Probe, and the upcoming ESA (European Space Agency)/NASA Solar Orbiter, due to launch in 2020. PUNCH will be able to image, in real time, the structures in the solar atmosphere that these missions encounter by blocking out the bright light of the Sun and examining the much fainter atmosphere.

    Together, these missions will investigate how the star we live with drives radiation in space. PUNCH is led by Craig DeForest at the Southwest Research institute in Boulder, Colorado. Including launch costs, PUNCH is being funded for no more than $165 million.

    TRACERS

    The second mission is Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites, or TRACERS.

    NASA TRACER mission


    NASA TRACER MIssion

    The TRACERS investigation was partially selected as a NASA-launched rideshare mission, meaning it will be launched as a secondary payload with PUNCH. NASA’s Science Mission Directorate is emphasizing secondary payload missions as a way to obtain greater science return. TRACERS will observe particles and fields at the Earth’s northern magnetic cusp region – the region encircling Earth’s pole, where our planet’s magnetic field lines curve down toward Earth. Here, the field lines guide particles from the boundary between Earth’s magnetic field and interplanetary space down into the atmosphere.

    In the cusp area, with its easy access to our boundary with interplanetary space, TRACERS will study how magnetic fields around Earth interact with those from the Sun. In a process known as magnetic reconnection, the field lines explosively reconfigure, sending particles out at speeds that can approach the speed of light. Some of these particles will be guided by the Earth’s field into the region where TRACERS can observe them.

    Magnetic reconnection drives energetic events all over the universe, including coronal mass ejections and solar flares on the Sun. It also allows particles from the solar wind to push into near-Earth space, driving space weather there. TRACERS will be the first space mission to explore this process in the cusp with two spacecraft, providing observations of how processes change over both space and time. The cusp vantage point also permits simultaneous observations of reconnection throughout near-Earth space. Thus, it can provide important context for NASA’s Magnetospheric Multiscale mission, which gathers detailed, high-speed observations as it flies through single reconnection events at a time.

    TRACERS’ unique measurements will help with NASA’s mission to safeguard our technology and astronauts in space. The mission is led by Craig Kletzing at the University of Iowa in Iowa City. Not including rideshare costs, TRACERS is funded for no more than $115 million.

    Launch date for the two missions is no later than August 2022. Both programs will be managed by the Explorers Program Office at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The Explorers Program, the oldest continuous NASA program, is designed to provide frequent, low-cost access to space using principal investigator-led space science investigations relevant to the work of NASA’s Science Mission Directorate in astrophysics and heliophysics. The program is managed by Goddard for the Science Mission Directorate, which conducts a wide variety of research and scientific exploration programs for Earth studies, space weather, the solar system and universe.

    For additional information, and the chance to ask more about the missions, please join us for a Reddit Ask Me Anything at 12:30 – 1:30 p.m. EDT June 21.

    For more information about the Explorers Program, visit:

    https://explorers.gsfc.nasa.gov

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 8:45 am on June 4, 2019 Permalink | Reply
    Tags: "A Twisted Tale of Sunspots", , , Solar research   

    From Medium: “A Twisted Tale of Sunspots” 

    From Medium

    May 28. 2019
    James Maynard

    One of the greatest questions in solar astronomy may have an answer after more than 400 years, thanks to an inquisitive team of German researchers. Every eleven years, the population of sunspots seen on the surface of our local star reaches a maximum, before dying out. Another population of sunspots then begin to appear (this time with their poles reversed from the previous cycle) before they too peak and fade away. This process may be well-known, but the reason for these 11-year peaks has remained a mystery, until now.

    The magnetic field of the Sun may be affected by the gravitational forces of Venus, Earth, and Jupiter, resulting in the cyclical sunspot cycle, a new study suggests. Researchers compared solar cycles to the positions of planets, finding the gravitational forces of these three worlds acts like a cosmic clock, regulating the solar cycle.

    “There is an astonishingly high level of concordance: what we see is complete parallelism with the planets over the course of 90 cycles. Everything points to a clocked process,” explained Frank Stefani of the German-based research institute Helmholtz-Zentrum Dresden-Rossendorf (HZDR).

    1
    The sunspot cycle can be easily seen in this graphic, produced by NASA in 2017. We are currently at a low point in the cycle. Image credit: NASA/ARC/Hathaway

    You Missed a Spot Right There

    Sunspots were first clearly seen between the years 1610 and 1611, in the years following the invention of the telescope. Although Galileo is often given credit for the discovery, several pioneering astronomers of the era reported finding the distinctive dark spots on the Moon around the same time.

    2
    A sunspot, seen by the Solar Dynamics Observatory (SDO) shows off it’s powerful magnetic field. Image credit: NASA’s Goddard Space Flight Center/SDO

    NASA/SDO

    The publication of the first paper recognizing these features, by Dutch astronomer Johannes Fabricius, shocked the zeitgeist of early 17th Century society, which always held a belief in a perfect, unchanging, featureless Sun.

    3
    De Maculis in Sole observatis et Apparente earum cum Sole Conversione Narratio (Narration on Spots Observed on the Sun and their Apparent Rotation with the Sun), published in June 1611, was the first scientific paper published describing sunspots. Public domain image.

    Everybody Line up!

    The greatest gravitational force of planets on the Sun occurs once every 11.07 years, when Venus, Earth, and Jupiter come into alignment. Gravitational pull from this arrangement results in tidal forces on the Sun, similar to the way our own Moon draws oceans upward, creating tides.

    This effect is not strong enough to affect the interior of our stellar companion, so the timing of this alignment was previously overlooked in earlier studies of sunspot cycles. However, a physical effect known as the Tayler instability is capable of altering the behavior of conductive liquids or a plasma.

    The Tayler instability alters the rate of flow of material (the flux) in an object, like the Sun, and can affect magnetic fields. This effect can be triggered by relatively small movements in materials like the plasma found at the surface of the Sun. Due to this effect, these relatively minor tidal forces can alter the relationship of sunspots to their direction of travel. This measurement, known as the helicity of a region of plasma, alters the solar dynamo (the physical process which generates the magnetic field of our parent star).

    “Magnetic fields are a little like rubber bands. They consist of continuous loops of lines of force that have both tension and pressure. Like rubber bands, magnetic fields can be strengthened by stretching them, twisting them, and folding them back on themselves. This stretching, twisting, and folding is done by the fluid flows within the Sun,” The Marshall Space Flight Center explains.


    A video explaining the process resulting in the formation of sunspots. Credit: NASA Goddard

    Stefani had his doubts whether or not tidal forces from the planets could alter an event as powerful as the solar dynamo. However, once he realized the Tayler instability could provide the trigger for the process, Stefani and his team began developing a computer simulation to model the process.

    “I asked myself: What would happen if the plasma was impacted on by a small, tidal-like perturbation? The result was phenomenal. The oscillation was really excited and became synchronized with the timing of the external perturbation,” Stefani explains.

    Sun, Spot, Sun!

    The motion of the sun is complex, with multiple effects contributing to its intricate dance. As the sun rotates, the equator moves faster than the material near the poles. In a process known as the omega effect, lines of the sun’s magnetic field are pulled and stretched near the equator, creating a bend in the direction of the solar equator.

    A little-understood alpha effect then affects the magnetic lines, pushing them toward their original alignment, resulting in a twisting of the lines of force.

    3
    Magnetic lines can be seen above sunspots in this image of charged particles, captured in extreme ultraviolet light. Image credit: NASA/GSFC/Solar Dynamics Observatory.

    These actions create the cool, dark areas we know as sunspots. While most of the surface of the Sun glows around 5,500 degrees Celsius (9,900 Fahrenheit), sunspots remain at a relatively cool 3,200 Celsius (5,800 Fahrenheit). Sunspots are still fairly bright, only appearing dark against the torrid backdrop of the solar surface.

    This new model, folding tidal forces into the complex processes of the solar dynamo, could explain several questions astronomers and physicists have about the solar dynamo, and how it affects our parent star.

    The Parker Solar Probe is currently in orbit around the Sun, in a mission to study our stellar companion up close.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker

    This program could answer a multitude of mysteries concerning Sun over the next few years.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Medium

    Medium is an online publishing platform developed by Evan Williams, and launched in August 2012. It is owned by A Medium Corporation. The platform is an example of social journalism, having a hybrid collection of amateur and professional people and publications, or exclusive blogs or publishers on Medium, and is regularly regarded as a blog host.

    Williams developed Medium as a way to publish writings and documents longer than Twitter’s 140-character (now 280-character) maximum.

     
  • richardmitnick 5:23 pm on April 17, 2019 Permalink | Reply
    Tags: "Exploring Filaments on the Sun", , , , , , Solar research   

    From AAS NOVA: “Exploring Filaments on the Sun” 

    AASNOVA

    From AAS NOVA

    17 April 2019
    Susanna Kohler

    1
    This image of the Sun’s chromosphere reveals dark cuts across its surface: solar filaments. A new study explores how these filaments are built. [NOAA/SEL/USAF]

    Images of the Sun’s chromosphere often reveal dark threads cutting across the Sun’s face. New research has now explored how these solar filaments are built from magnetic fields and plasma.

    Two-Faced Structures

    3
    A solar eruptive prominence as seen in extreme UV light on March 30, 2010, with Earth superimposed for a sense of scale. [NASA/SDO]

    NASA/SDO

    Solar filaments may look like deep cracks in the Sun’s façade, but in reality, they are enormous arcs of hot plasma that extend above the Sun’s surface. Because this plasma is slightly cooler than the solar surface below, they appear dark against the hotter background.

    Unfamiliar with filaments? You’ve likely seen plenty of them in images — but from a different angle! Filaments are the same structures as solar prominences, the loops of plasma we can see suspended above the Sun’s limbs. When prominences appear on the side of the Sun facing us, they take the form of filaments from our point of view.

    Shaped by Fields

    Filaments are often associated with various forms of solar activity. They last for days, frequently hanging above active regions of the Sun; filament channels are often the origin of eruptions from the Sun’s surface. To better understand our active and energetic Sun, understanding the structures of filaments is an important step.

    Unfortunately, this is challenging! We know that filament structure is largely due to the magnetic fields — whose forces suspend the filaments against the downward pull of gravity — but we don’t have the ability to directly measure the magnetic field in the Sun’s atmosphere. A team of scientists at the University of Science and Technology of China has instead taken an indirect approach: they explored filaments by looking at the motion of plasma along them.

    4
    Top: time-distance map characterizing the oscillations at one position on the filament spine. Bottom: a Doppler map, averaged over time, that shows the rotation around the spine of the filament. Blue indicates motion toward the observer, red away. [Adapted from Awasthi et al. 2019]

    A Double Decker?

    Scientists Arun Awasthi, Rui Liu, and Yuming Wang examined observations of a filament that appeared near active region AR 12685 in October 2017, captured with the 1-m New Vacuum Solar Telescope in China. The team used these high-resolution images to explore bulk motions of plasma in the filament.

    Awasthi and collaborators found that the filament displayed two different types of motion: rotation around its central spine, and longitudinal oscillations along its spine. The longitudinal oscillations in the eastern segment of the filament were distinct from those in the west, suggesting that the magnetic field lines underneath these two segments have different lengths and curvatures.

    On the whole, the motions observed in the filament indicate that magnetic structure for filaments is complicated. The authors argue that more than one model is likely at work; they propose a “double-decker” picture for the filament in which a flux rope (a twisted bundle of magnetic field lines) sits on top of a sheared arcade (a series of distorted loops).

    Awasthi and collaborators conclude with specific predictions of indicators we can look for in future filament observations to test this model. If correct, this view of filament structure brings us a little closer to understanding the complex magnetic fields that control solar activity.

    Citation

    “Double-decker Filament Configuration Revealed by Mass Motions,” Arun Kumar Awasthi et al 2019 ApJ 872 109.
    https://iopscience.iop.org/article/10.3847/1538-4357/aafdad/meta

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    1

    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
  • richardmitnick 3:47 pm on April 5, 2019 Permalink | Reply
    Tags: "And the Blobs Just Keep on Coming", , , Solar research, Two German-NASA Helios spacecraft which launched in 1974 and 1976 to study the Sun   

    From NASA Goddard Space Flight Center: “And the Blobs Just Keep on Coming” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    April 4, 2019

    Lina Tran
    lina.tran@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    When Simone Di Matteo first saw the patterns in his data, it seemed too good to be true. “It’s too perfect!” Di Matteo, a space physics Ph.D. student at the University of L’Aquila in Italy, recalled thinking. “It can’t be real.” And it wasn’t, he’d soon find out.

    Di Matteo was looking for long trains of massive blobs — like a lava lamp’s otherworldly bubbles, but anywhere from 50 to 500 times the size of Earth — in the solar wind. The solar wind, whose origins aren’t yet fully understood, is the stream of charged particles that blows constantly from the Sun. Earth’s magnetic field, called the magnetosphere, shields our planet from the brunt of its radiation. But when giant blobs of solar wind collide with the magnetosphere, they can trigger disturbances there that interfere with satellites and everyday communications signals.

    In his search, Di Matteo was re-examining archival data from the two German-NASA Helios spacecraft, which launched in 1974 and 1976 to study the Sun.

    NASA/DLR Helios spacecraft

    1
    Engineers inspect the Helios 2 spacecraft.
    Credits: NASA’s Goddard Space Flight Center

    But this was 45-year-old data he’d never worked with before. The flawless, wave-like patterns he initially found hinted that something was leading him astray.

    It wasn’t until uncovering and removing those false patterns that Di Matteo found exactly what he was looking for: dotted trails of blobs that oozed from the Sun every 90 minutes or so. The scientists published their findings in JGR Space Physics on Feb. 21, 2019. They think the blobs could shed light on the solar wind’s beginnings. Whatever process sends the solar wind out from the Sun must leave signatures on the blobs themselves.

    Making Way for New Science

    Di Matteo’s research was the start of a project NASA scientists undertook in anticipation of the first data from NASA’s Parker Solar Probe mission, which launched in 2018.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker

    Over the next seven years, Parker will fly through unexplored territory, soaring as close as 4 million miles from the Sun. Before Parker, the Helios 2 satellite held the record for the closest approach to the Sun at 27 million miles, and scientists thought it might give them an idea of what to expect. “When a mission like Parker is going to see things no one has seen before, just a hint of what could be observed is really helpful,” Di Matteo said.

    The problem with studying the solar wind from Earth is distance. In the time it takes the solar wind to race across the 93 million miles between us and the Sun, important clues to the wind’s origins — like temperature and density — fade. “You’re constantly asking yourself, ‘How much of what I’m seeing here is because of evolution over four days in transit, and how much came straight from the Sun?’” said solar scientist Nicholeen Viall, who advised Di Matteo during his research at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Helios data — some of which was collected at just one-third the distance between the Sun and Earth — could help them begin to answer these questions.

    Modeling Blobs

    The first step was tracing Helios’ measurements of the blobs to their source on the Sun. “You can look at spacecraft data all you want, but if you can connect it back to where it came from on the Sun, it tells a more complete story,” said Samantha Wallace, one of the study collaborators and a physics Ph.D. student at the University of New Mexico in Albuquerque.

    Wallace used an advanced solar wind model to link magnetic maps of the solar surface to Helios’ observations, a tricky task since computer languages and data conventions have changed greatly since Helios’ days. Now, the researchers could see what sorts of regions on the Sun were likely to bud into blobs of solar wind.


    In the days before Parker Solar Probe, the record-breaking spacecraft for speed and closest approach to the Sun were the two Helios probes, launched in the mid-1970s. This visualization shows the orbits of Helios 1 and Helios 2, from an oblique view above the ecliptic plane.
    Credits: Tom Bridgman/NASA’s Scientific Visualization Studio

    Sifting the Evidence

    Then, Di Matteo searched the data for specific wave patterns. They expected conditions to alternate — hot and dense, then cold and tenuous — as individual blobs engulfed the spacecraft and moved on, in a long line.

    The picture-perfect patterns Di Matteo first found worried him. “That was a red flag,” Viall said. “The actual solar wind doesn’t have such precise, clean periodicities. Usually when you get such a precise frequency, it means some instrument effect is going on.” Maybe there was some element of the instrument design they weren’t considering, and it was imparting effects that had to be separated from true solar wind patterns.

    Di Matteo needed more information on the Helios instruments. But most researchers who worked on the mission have long since retired. He did what anyone else would do, and turned to the internet.

    Many Google searches and a weekend of online translators later, Di Matteo unearthed a German instruction manual that describes the instruments dedicated to the mission’s solar wind experiment. Decades ago, when Helios was merely a blueprint and before anyone ever launched a spacecraft to the Sun, scientists didn’t know how best to measure the solar wind. To prepare themselves for different scenarios, Di Matteo learned, they equipped the probes with two different instruments that would each measure certain solar wind properties in their own way. This was the culprit responsible for Di Matteo’s perfect waves: the spacecraft itself, as it alternated between two instruments.

    After they removed segments of data taken during routine instrument-switching, the researchers looked again for the blobs. This time, they found them. The team describes five instances that Helios happened to catch trains of blobs. While scientists have spotted these blobs from Earth before, this is the first time they’ve studied them this close to the Sun, and with this level of detail. They outline the first conclusive evidence that the blobs are hotter and denser than the typical solar wind.

    The Return of the Blobs

    Whether blob trains bubble in 90-minute intervals continuously or in spurts, and how much they vary between themselves, is still a mystery. “This is one of those studies that brought up more questions than we answered, but that’s perfect for Parker Solar Probe,” Viall said.

    Parker Solar Probe aims to study the Sun up close, seeking answers to basic questions about the solar wind. “This is going to be very helpful,” said Aleida Higginson, the mission’s deputy project scientist at Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. “If you want to even begin to understand things you’ve never seen before, you need to know what we’ve measured before and have a solid scientific interpretation for it.”

    Parker Solar Probe performs its second solar flyby on April 4, which brings it 15 million miles from the Sun — already cutting Helios 2’s record distance in half. The researchers are eager to see if blobs show up in Parker’s observations. Eventually, the spacecraft will get so close it could catch blobs right after they’ve formed, fresh out of the Sun.

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    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

     
  • richardmitnick 3:00 pm on April 5, 2019 Permalink | Reply
    Tags: , , , Coronal rain, , Emily Mason, Helmet streamers, , , , Solar research,   

    From NASA Goddard Space Flight Center: Women in STEM “Unexpected Rain on Sun Links Two Solar Mysteries” Emily Mason 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    April 5, 2019

    Miles Hatfield
    miles.s.hatfield@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    For five months in mid 2017, Emily Mason did the same thing every day. Arriving to her office at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, she sat at her desk, opened up her computer, and stared at images of the Sun — all day, every day. “I probably looked through three or five years’ worth of data,” Mason estimated. Then, in October 2017, she stopped. She realized she had been looking at the wrong thing all along.

    Mason, a graduate student at The Catholic University of America in Washington, D.C., was searching for coronal rain: giant globs of plasma, or electrified gas, that drip from the Sun’s outer atmosphere back to its surface. But she expected to find it in helmet streamers, the million-mile tall magnetic loops — named for their resemblance to a knight’s pointy helmet — that can be seen protruding from the Sun during a solar eclipse. Computer simulations predicted the coronal rain could be found there. Observations of the solar wind, the gas escaping from the Sun and out into space, hinted that the rain might be happening. And if she could just find it, the underlying rain-making physics would have major implications for the 70-year-old mystery of why the Sun’s outer atmosphere, known as the corona, is so much hotter than its surface. But after nearly half a year of searching, Mason just couldn’t find it. “It was a lot of looking,” Mason said, “for something that never ultimately happened.”

    1
    Mason searched for coronal rain in helmet streamers like the one that appears on the left side of this image, taken during the 1994 eclipse as viewed from South America. A smaller pseudostreamer appears on the western limb (right side of image). Named for their resemblance to a knight’s pointy helmet, helmet streamers extend far into the Sun’s faint corona and are most readily seen when the light from the Sun’s bright surface is occluded. Credits: © 1994 Úpice observatory and Vojtech Rušin, © 2007 Miloslav Druckmüller

    The problem, it turned out, wasn’t what she was looking for, but where. In a paper published today in The Astrophysical Journal Letters, Mason and her coauthors describe the first observations of coronal rain in a smaller, previously overlooked kind of magnetic loop on the Sun. After a long, winding search in the wrong direction, the findings forge a new link between the anomalous heating of the corona and the source of the slow solar wind — two of the biggest mysteries facing solar science today.

    How It Rains on the Sun

    Observed through the high-resolution telescopes mounted on NASA’s SDO spacecraft, the Sun – a hot ball of plasma, teeming with magnetic field lines traced by giant, fiery loops — seems to have few physical similarities with Earth.

    NASA/SDO

    But our home planet provides a few useful guides in parsing the Sun’s chaotic tumult: among them, rain.

    On Earth, rain is just one part of the larger water cycle, an endless tug-of-war between the push of heat and pull of gravity. It begins when liquid water, pooled on the planet’s surface in oceans, lakes, or streams, is heated by the Sun. Some of it evaporates and rises into the atmosphere, where it cools and condenses into clouds. Eventually, those clouds become heavy enough that gravity’s pull becomes irresistible and the water falls back to Earth as rain, before the process starts anew.

    On the Sun, Mason said, coronal rain works similarly, “but instead of 60-degree water you’re dealing with a million-degree plasma.” Plasma, an electrically-charged gas, doesn’t pool like water, but instead traces the magnetic loops that emerge from the Sun’s surface like a rollercoaster on tracks.

    2
    Coronal rain, like that shown in this movie from NASA’s SDO in 2012, is sometimes observed after solar eruptions, when the intense heating associated with a solar flare abruptly cuts off after the eruption and the remaining plasma cools and falls back to the solar surface. Mason was searching for coronal rain not associated with eruptions, but instead caused by a cyclical process of heating and cooling similar to the water cycle on Earth.
    Credits: NASA’s Solar Dynamics Observatory/Scientific Visualization Studio/Tom Bridgman, Lead Animator

    At the loop’s foot points, where it attaches to the Sun’s surface, the plasma is superheated from a few thousand to over 1.8 million degrees Fahrenheit. It then expands up the loop and gathers at its peak, far from the heat source. As the plasma cools, it condenses and gravity lures it down the loop’s legs as coronal rain.

    Mason was looking for coronal rain in helmet streamers, but her motivation for looking there had more to do with this underlying heating and cooling cycle than the rain itself. Since at least the mid-1990s, scientists have known that helmet streamers are one source of the slow solar wind, a comparatively slow, dense stream of gas that escapes the Sun separately from its fast-moving counterpart. But measurements of the slow solar wind gas revealed that it had once been heated to an extreme degree before cooling and escaping the Sun. The cyclical process of heating and cooling behind coronal rain, if it was happening inside the helmet streamers, would be one piece of the puzzle.

    The other reason connects to the coronal heating problem — the mystery of how and why the Sun’s outer atmosphere is some 300 times hotter than its surface. Strikingly, simulations have shown that coronal rain only forms when heat is applied to the very bottom of the loop. “If a loop has coronal rain on it, that means that the bottom 10% of it, or less, is where coronal heating is happening,” said Mason. Raining loops provide a measuring rod, a cutoff point to determine where the corona gets heated. Starting their search in the largest loops they could find — giant helmet streamers — seemed like a modest goal, and one that would maximize their chances of success.

    She had the best data for the job: Images taken by NASA’s Solar Dynamics Observatory, or SDO, a spacecraft that has photographed the Sun every twelve seconds since its launch in 2010. But nearly half a year into the search, Mason still hadn’t observed a single drop of rain in a helmet streamer. She had, however, noticed a slew of tiny magnetic structures, ones she wasn’t familiar with. “They were really bright and they kept drawing my eye,” said Mason. “When I finally took a look at them, sure enough they had tens of hours of rain at a time.”

    At first, Mason was so focused on her helmet streamer quest that she made nothing of the observations. “She came to group meeting and said, ‘I never found it — I see it all the time in these other structures, but they’re not helmet streamers,’” said Nicholeen Viall, a solar scientist at Goddard, and a coauthor of the paper. “And I said, ‘Wait…hold on. Where do you see it? I don’t think anybody’s ever seen that before!’”

    A Measuring Rod for Heating

    These structures differed from helmet streamers in several ways. But the most striking thing about them was their size.

    “These loops were much smaller than what we were looking for,” said Spiro Antiochos, who is also a solar physicist at Goddard and a coauthor of the paper. “So that tells you that the heating of the corona is much more localized than we were thinking.”

    3
    Mason’s article analyzed three observations of Raining Null-Point Topologies, or RNTPs, a previously overlooked magnetic structure shown here in two wavelengths of extreme ultraviolet light. The coronal rain observed in these comparatively small magnetic loops suggests that the corona may be heated within a far more restricted region than previously expected. Credits: NASA’s Solar Dynamics Observatory/Emily Mason

    While the findings don’t say exactly how the corona is heated, “they do push down the floor of where coronal heating could happen,” said Mason. She had found raining loops that were some 30,000 miles high, a mere two percent the height of some of the helmet streamers she was originally looking for. And the rain condenses the region where the key coronal heating can be happening. “We still don’t know exactly what’s heating the corona, but we know it has to happen in this layer,” said Mason.

    A New Source for the Slow Solar Wind

    But one part of the observations didn’t jibe with previous theories. According to the current understanding, coronal rain only forms on closed loops, where the plasma can gather and cool without any means of escape. But as Mason sifted through the data, she found cases where rain was forming on open magnetic field lines. Anchored to the Sun at only one end, the other end of these open field lines fed out into space, and plasma there could escape into the solar wind. To explain the anomaly, Mason and the team developed an alternative explanation — one that connected rain on these tiny magnetic structures to the origins of the slow solar wind.

    In the new explanation, the raining plasma begins its journey on a closed loop, but switches — through a process known as magnetic reconnection — to an open one. The phenomenon happens frequently on the Sun, when a closed loop bumps into an open field line and the system rewires itself. Suddenly, the superheated plasma on the closed loop finds itself on an open field line, like a train that has switched tracks. Some of that plasma will rapidly expand, cool down, and fall back to the Sun as coronal rain. But other parts of it will escape – forming, they suspect, one part of the slow solar wind.

    Mason is currently working on a computer simulation of the new explanation, but she also hopes that soon-to-come observational evidence may confirm it. Now that Parker Solar Probe, launched in 2018, is traveling closer to the Sun than any spacecraft before it, it can fly through bursts of slow solar wind that can be traced back to the Sun — potentially, to one of Mason’s coronal rain events.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker

    After observing coronal rain on an open field line, the outgoing plasma, escaping to the solar wind, would normally be lost to posterity. But no longer. “Potentially we can make that connection with Parker Solar Probe and say, that was it,” said Viall.

    Digging Through the Data

    As for finding coronal rain in helmet streamers? The search continues. The simulations are clear: the rain should be there. “Maybe it’s so small you can’t see it?” said Antiochos. “We really don’t know.”

    But then again, if Mason had found what she was looking for she might not have made the discovery — or have spent all that time learning the ins and outs of solar data.

    “It sounds like a slog, but honestly it’s my favorite thing,” said Mason. “I mean that’s why we built something that takes that many images of the Sun: So we can look at them and figure it out.”

    Related:

    IRIS Spots Plasma Rain on Sun’s Surface

    NASA IRIS spacecraft, a spacecraft that takes spectra in three passbands, allowing us to probe different layers of the solar atmosphere


    And the Blobs Just Keep on Coming

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    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

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: