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  • richardmitnick 11:03 am on November 9, 2017 Permalink | Reply
    Tags: , , , , Cloudy with a chance of coronal mass ejections, Coronal Mass Ejections, ,   

    From astrobites: “Cloudy with a chance of coronal mass ejections” 

    Astrobites bloc


    Nov 9, 2017
    Kerrin Hensley

    Title: Using the Coronal Evolution to Successfully Forward Model CMEs’ In Situ Magnetic Profiles
    Authors: Christina Kay and Nat Gopalswamy
    First Author’s Institution: NASA Goddard Space Flight Center

    Status: Accepted to the Journal of Geophysical Research – Space Physics, open access

    Coronal Mass Ejections and You

    An eruption on April 16, 2012 was captured here by NASA’s Solar Dynamics Observatory in the 304 Angstrom wavelength, which is typically colored in red. Credit: NASA/SDO/AIA


    Coronal mass ejections (CMEs) are immense eruptions of solar plasma and magnetic fields. When a CME strikes a planet, it can have huge effects; over billions of years, CMEs can strip away a planet’s atmosphere. In the short term, CMEs wreak havoc at Earth by causing dangerous and costly geomagnetic storms.

    In 1859, a CME impacted the Earth and caused the most intense geomagnetic storm ever recorded, resulting in stunning auroral displays over much of the northern hemisphere (Figure 1) and widespread failure of telegraph systems. An event of this magnitude today would cause huge damage to power grids, satellites, and oil pipelines—resulting in a trillion dollars of damage in the United States alone. So, how can we prevent this from occurring?

    Enter the growing field of space weather forecasting. Although we can’t stop the Sun from ejecting CMEs, we can try to figure out if a given CME will hit the Earth, and how severe the resulting geomagnetic storm will be if it does. The severity of a geomagnetic storm is linked to the CME’s magnetic field conditions, especially the magnitude of the southward-pointing magnetic field (i.e. the component of the magnetic field that opposes the Earth’s magnetic field at the equator). If the CME’s properties can be accurately estimated, the severity of the resulting geomagnetic storm can be estimated too, allowing for power grids and satellites to be put into safe mode if necessary.

    See the full article here .

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    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

  • richardmitnick 8:02 am on December 4, 2016 Permalink | Reply
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    From SPACE.com: “Sun Storm May Have Caused Flare-Up of Rosetta’s Comet” 

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    December 2, 2016
    Nola Taylor Redd

    The ESA/NASA Solar and Heliospheric Observatory spacecraft captured this image of a coronal mass ejection erupting on the sun on Sept. 30, 2015.
    Credit: ESA/NASA/SOHO


    Material from the sun may have caused Comet 67P/Churyumov-Gerasimenko to flare up nearly 100 times brighter than average in some parts of the visual spectrum, new research reports.

    At about the same time that charged solar particles slammed into Comet 67P, the European Space Agency’s (ESA) Rosetta spacecraft observed that the icy wanderer dramatically brightened. Initially, scientists assumed that unusual effect came from jets of material within the comet. However, newly released observations of 67P suggest that a burst of charged particles from the sun, known as a coronal mass ejection (CME), could have caused the change.

    “The [brightening] was characterized by a substantial increase in the hydrogen, carbon and oxygen emission lines that increased by roughly 100 times their average brightness on the night of Oct. 5 and 6, 2015,” John Noonan told Space.com. Noonan, who just completed his undergraduate degree at the University of Colorado at Boulder, presented the research at the Division for Planetary Sciences meeting in Pasadena, California, in October.

    After reading a report of a CME that hit 67P at the same time, Noonan realized that the increased emissions from water, carbon dioxide and molecular oxygen observed by Rosetta’s R-Alice instrument could all be explained by the collision of the comet with material jettisoned from the sun.

    “This doesn’t yet rule out that an outburst could have happened, but it looks possible that all of the emissions could have been caused by the CME impact,” Noonan said.

    A simulation reveals how the plasma of the solar wind should interact with Comet 67P/C-G. Credit: Modelling and simulation: Technische Universität Braunschweig and Deutsches Zentrum für Luft- und Raumfahrt; Visualisation: Zuse-Institut Berlin

    Colliding particles

    Rosetta entered orbit around Comet 67P in August 2014, making detailed observations until the probe deliberately crashed into the icy body at the end of its mission in September 2016.

    So Rosetta was tagging along when Comet 67P made its closest pass to the sun in August 2015. (Such “perihelion passages” occur once every 6.45 years — the time it takes the icy object to circle the sun.)

    As 67P neared the sun, newly warmed jets began to release gas from the surface, building up the cloud of debris around the nucleus known as the coma. Jets continued to spout throughout Rosetta’s observations as different regions of the comet rotated into sunlight. Such spouts were initially credited with the extreme brightening that took place in October 2015.

    In addition to warming the comet, the sun also interacted with it through its solar wind, the constant rush of charged particles streaming into space in all directions. Occasionally, the sun also blows off the collections of plasma and charged particles known as CMEs. When CMEs collide with Earth, they can interact with the planet’s magnetic field to create dazzling auroral displays; this interaction can also damage power grids and satellites.

    Niklas Edberg, a scientist on the Rosetta Plasma Consortium Ion and Electron Spectrometer instrument on the spacecraft, and his colleagues recently reported that RPC/IES observed a CME impact on Rosetta at the same time as the bizarre brightening. The ESA/NASA Solar and Heliospheric Observatory (SOHO) spacecraft detected the CME as it left the sun on Sept. 30, 2015.

    According to Edberg, the CME compressed the plasma material around the comet. Because Rosetta was orbiting within the coma, the probe hadn’t sampled any material streaming from the solar wind since the previous April, and wasn’t expected to do so for several more months. When the CME slammed into the comet, however, the coma was compressed and Rosetta briefly tasted part of the solar wind once again.

    “This suggests that the plasma environment had been compressed significantly, such that the solar wind ions could briefly reach the detector, and provides further evidence that these signatures in the cometary plasma environment are indeed caused by a solar wind event, such as a CME,” Edberg and his team wrote in their study, which was published in the journal Monthly Notices of the Royal Astronomical Society in September 2016.

    Forces at play

    For Noonan, the realization that a CME had impacted the comet at the same time of its unusual brightening had an illuminating effect.

    “I read this [Edberg et al.] paper and realized that the substantial increase in electron density could account for the increased emissions from the coma that R-Alice observed, and set about testing what the density of the coma’s water, carbon dioxide and molecular oxygen components would have to be to match what we saw,” Noonan said.

    Charged particles from the CME may have excited cometary material, causing it to release photons, he added. Some of the observed changes could be created only by interacting electrons, causing what Noonan called “unique fingerprints” that let the scientists know electrons were impacting the material. Of special importance was the transition of oxygen line in the spectra, a change that can only be caused by electrons.

    “During the course of the CME, we saw this line increase in strength by roughly hundredfold,” Noonan said.

    The charged particles were unlikely to have come from the solar wind, which Noonan said would be blocked from ever penetrating this deep.

    While CMEs have been observed around other comets, they have only been viewed remotely. From such great distances, only large-scale changes in the comets’ comas and tails could be observed, Edberg said. Over the course of its two-year mission at Comet 67P, Rosetta’s close orbit allowed it to observe other CMEs interacting with the comet, but Noonan said none were as noticeable as the event of Oct. 5-6, 2015.

    “Prior to Rosetta, these electron impact emissions had never been observed around a comet, and it was these emissions that gave away that the CME might be a factor in causing them,” Noonan said.

    He cautioned that it isn’t a given that the influx of charged particles caused the bizarre brightening, which still could be caused by the jets of material.

    “At this point, we are still working to understand exactly what was the cause to see if it was the CME, and outburst, or both, that caused the emission,” Noonan said.

    Given the timing of the impact, however, it is unlikely that the flare-up was the result of gas released by jets alone.

    “There are more forces at play than just a higher density of gas,” Noonan said.

    See the full article here .

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  • richardmitnick 9:48 am on October 31, 2016 Permalink | Reply
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    From Science: “Solar storms can weaken Earth’s magnetic field” 

    Science Magazine

    A coronal mass ejection in 2015, seen here by NASA’s Solar Dynamics Observatory, ended up weakening Earth’s magnetic field.

    Oct. 31, 2016
    Katherine Kornei

    The sun’s warm glow can sometimes turn menacing. Solar storms can shoot plasma wrapped in bits of the sun’s magnetic field into space, sweeping past Earth and disabling satellites, causing widespread blackouts, and disrupting GPS-based navigation. Now, a new study suggests that one such “coronal mass ejection” in 2015 temporarily weakened Earth’s protective magnetic field, allowing solar plasma and radiation from the same storm to more easily reach the atmosphere, potentially posing a danger to astronauts. The study also suggests a potential way to predict such storms in the future.

    On 21 June 2015, a NASA spacecraft called the Solar and Heliospheric Observatory recorded a coronal mass ejection blasting off the sun at roughly 1300 kilometers per second.


    When the burst reached Earth roughly 40 hours later, its magnetic field was oriented opposite to Earth’s own magnetic field, which caused the fields to be attracted to each other and to interact strongly. “It is like bringing two magnets close together,” says physicist Sunil Gupta of the Tata Institute of Fundamental Research in Mumbai, India, and lead author of the new study.

    The resulting interaction converted magnetic energy into kinetic energy and sent charged particles such as cosmic rays raining down on Earth’s magnetosphere, the region around Earth where its own magnetic field is stronger than other magnetic fields in space. The National Oceanic and Atmospheric Administration (NOAA) rated the geomagnetic storm 4 out of 5 on its scale of storm severity. Radio blackouts were reported, and the aurora borealis was spotted as far south as Texas.

    Gupta and his team collected data from a telescope in India that measures the number of charged particles called muons that are created as byproducts when cosmic rays hit Earth’s atmosphere. Looking at data from 22 June 2015, they found a statistically significant spike in the number of muons that day. This result was consistent with a weakening of Earth’s magnetic field that allowed cosmic rays to stream more freely through Earth’s magnetnosphere and into the atmosphere without being deflected.

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

    “The weakening of Earth’s magnetic field opens up floodgates for low-energy solar plasma to pour into the atmosphere,” says Gupta, whose team reports its findings this month in Physical Review Letters.

    Overall, the team showed that Earth’s magnetic field is susceptible to temporary damage, rendering our planet’s atmosphere the last line of defense against energetic particles from space. Without Earth’s magnetic field, astronauts above the atmosphere are exposed to particles that can rip through human bodies and damage DNA, potentially causing cancer.

    The new results also suggest a possible method to detect impending geomagnetic storms. A successful early warning system is key to reducing the economic impact of such storms, which has been estimated by the National Academy of Sciences to be several trillion dollars in the most severe cases. Even with only a few hours of advance warning, power grids could redistribute currents to reduce their vulnerability to currents traveling through Earth and airplanes flying polar routes could be rerouted to avoid losing radio contact with controllers, for example.

    Gupta and his colleagues propose using muons as early detectors of geomagnetic storms. The scientists begin by assuming that particles with lower energies take longer to travel through turbulent magnetic fields, much like a lazy moth takes longer to cross a windy valley than a quick bee. They accordingly reasoned that the highly energetic cosmic rays creating muons would reach Earth’s atmosphere ahead of the solar plasma and lower-energy cosmic rays that can be the brunt of a geomagnetic storm. “The muon burst could in principle serve as an early warning system before a storm,” Gupta says. “But a lot of research needs to be done to make it a practical proposition.”

    James Chen, a plasma physicist at the Naval Research Laboratory in Washington, D.C., says that predicting the future might not be so simple. “[The muon burst] is part of an ongoing storm so it may have little forecasting value,” he says.

    The results of Gupta and his team are timely: NOAA issued an alert last week warning of an impending “strong” geomagnetic storm. However, even when spotted by spacecraft, the predicted arrival times of storms are uncertain because they are based on simulations of how coronal mass ejections propagate through space. An Earth-based early alert system, based on particle data, might give less warning but be significantly more accurate.

    Earlier this month, U.S. President Barack Obama signed an executive order mandating that the U.S. government “mitigate the effects of geomagnetic disturbances on the electrical power grid” and “ensure the timely redistribution of space weather alerts.” Our technological society, for all of its advances, is still susceptible to the whims of our closest star.

    See the full article here .

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  • richardmitnick 4:06 pm on February 10, 2016 Permalink | Reply
    Tags: , , , Coronal Mass Ejections, , Owens Valley Long Wavelength Array, ,   

    From Caltech: “Chasing Extrasolar Space Weather” 

    Caltech Logo

    Lori Dajose

    Earth’s magnetic field acts like a giant shield, protecting the planet from bursts of harmful charged solar particles that could strip away the atmosphere.

    Magnetosphere of Earth
    Earth’s magnetosphere

    Gregg Hallinan, an assistant professor of astronomy, aims to detect this kind of space weather on other stars to determine whether planets around these stars are also protected by their own magnetic fields and how that impacts planetary habitability.

    On Wednesday, February 10, at 8 p.m. in Beckman Auditorium, Hallinan will discuss his group’s efforts to detect intense radio emissions from stars and their effects on any nearby planets. Admission is free.

    What do you do?
    I am an astronomer. My primary focus is the study of the magnetic fields of stars, planets, and brown dwarfs—which are kind of an intermediate object between a planet and a star.

    Brown dwarf
    Brown dwarf

    Stars and their planets have intertwined relationships. Our sun, for example, produces coronal mass ejections, or CMEs, which are bubbles of hot plasma explosively ejected from the sun out into the solar system.

    Solar eruption 2012 by NASA's Solar Dynamic Observatory SDO

    Radiation and particles from these solar events bombard the earth and interact with the atmosphere, dominating the local “space weather” in the environment of Earth. Happily, our planet’s magnetic field shields and redirects CMEs toward the polar regions. This causes auroras—the colorful light in the sky commonly known as the Northern or Southern Lights.

    Auroras from around the world
    Auroras from around the world

    Our new telescope, the Owens Valley Long Wavelength Array, images the entire sky instantaneously and allows us to monitor extrasolar space weather on thousands of nearby stellar systems.

    Caltech Owens Valley Long Wavelength Array
    Caltech Owens Valley Long Wavelength Array

    When a star produces a CME, it also emits a bright burst of radio waves with a specific signature. If a planet has a magnetic field and it is hit by one of these CMEs, it will also become brighter in radio waves. Those radio signatures are very specific and allow you to measure very precisely the strength of the planet’s magnetic field. I am interested in detecting radio waves from exoplanets—planets outside of our solar system—in order to learn more about what governs whether or not a planet has a magnetic field.

    Why is this important?

    The presence of a magnetic field on a planet can tell us a lot. Like on our own planet, magnetic fields are an important line of defense against the solar wind, particularly explosive CMEs, which can strip a planet of its atmosphere. Mars is a good example of this. Because it didn’t have a magnetic field shielding it from the sun’s solar wind, it was stripped of its atmosphere long ago. So, determining whether a planet has a magnetic field is important in order to determine which planets could possibly have atmospheres and thus could possibly host life.

    How did you get into this line of work?

    From a young age, I was obsessed with astronomy—it’s all I cared for. My parents got me a telescope when I was 7 or 8, and from then on, that was it.

    As a grad student, I was looking at magnetic fields of cool—meaning low-temperature—objects. When I was looking at brown dwarfs, I found that they behave like planets in that they also have auroras. I had the idea that auroras could be the avenue to examine the magnetic fields of other planets. So brown dwarfs were my gateway into exoplanets.

    See the full article here .

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    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.”
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  • richardmitnick 7:59 am on January 26, 2016 Permalink | Reply
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    From SPACE.com: “Mysteriously Powerful Particles from Solar Explosions Unveiled in New Study” 

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    January 25, 2016
    Calla Cofield

    Solar eruption 2012 by NASA's Solar Dynamic Observatory SDO
    A photo of a solar eruption from Oct. 14, 2012, as seen by NASA’s Solar Dynamic Observatory. Credit: NASA/SDO


    A couple of times a month — sometimes more, sometimes less — an explosion goes off on the surface of the sun, releasing energy that’s equal to millions of hydrogen bombs.

    Mind boggling as that number is, this tremendous energy output cannot explain how material that is spit out by these explosions gets ramped up to nearly the speed of light. It’s like expecting a golf cart motor to power a Ferrari.

    In a new study, researchers provide a first-of-its-kind look under the hood of these solar eruptions, taking specific aim at the physical process that accelerates the superfast particles.

    Explosions on the sun

    There are currently 18 NASA space missions dedicated to studying our nearest star and its effect on the solar system. Some of these satellites stare directly at the sun almost nonstop, providing a 24/7 stream of images of the sun’s swirling, churning surface.

    When a solar eruption happens, these satellites also see the incredibly bright flashes of light that are called solar flares. Occasionally, the eruptions also hurl a cloud of extremely hot and electrically charged gas (called plasma) out into space. The expelled plasma is called a coronal mass ejection, or CME for short.

    A solar explosion releases roughly the same amount of energy that would come from “millions of 100-megaton hydrogen bombs,” according to NASA, where one hundred megatons equal to one hundred million metric tons of TNT.

    While that certainly sounds impressive, it’s hard to imagine something so enormous. The best way to understand the colossal nature of these events might be to consider an image taken by NASA that shows a particularly massive CME. For comparison, a snapshot of the Earth (to scale) is placed next to this great, flaming ribbon. The planet looks like a daisy in the path of a flamethrower.

    A solar explosion releases roughly the same amount of energy that would come from “millions of 100-megaton hydrogen bombs,” according to NASA, where one hundred megatons equal to one hundred million metric tons of TNT.

    Shockingly fast

    When an airplane breaks the sound barrier — physically overtaking the sound waves traveling in front of it — it creates a shock wave, and a deafening sonic boom. The boom is evidence that the shock wave is a source of energy.

    Bin Chen, a researcher at the Harvard-Smithsonian Center for Astrophysics is the lead author on a new research paper that provides the first solid observational evidence that ultraspeedy particles released during a solar eruption are accelerated by a kind of stationary shock wave called a “termination shock.”

    One of the intriguing elements of solar eruptions is that, unlike most explosions on Earth, they aren’t chemically driven. Rather, these sunshine bombs are detonated by a rapid release of magnetic energy. The same force that makes a magnet stick to a refrigerator or makes a compass needle point north is also responsible for these massive belches of light and material.

    The solar eruptions that create solar flares and CMEs occur when one of the sun’s magnetic-field lines break, and rapidly reconnects, near the surface. During the explosion, plasma is flung out into space, but others go back down toward the surface at incredibly high speeds, where they crash into more magnetic-field loops — kind of like a waterfall crashing into the surface of a pond. At the point of collision, a termination shock forms in the electrically charged plasma.

    “Charged particles that cross a [termination] shock can pick up the energy from the shock and get faster and faster. That’s how shock acceleration works,” Bin told Space.com.

    Chen and his coauthors saw evidence of this termination shock during a solar flare on March 3, 2012, using the Karl G. Jansky Very Large Array (VLA) in New Mexico.

    Karl G. Jansky Very Large Array (VLA)

    The recently upgraded telescope was beneficial for two reasons. First, it detects radio waves, which means it isn’t overwhelmed by the brightest flashes of light emitted during a solar flare. But looking at a solar flare radio frequencies does reveal the particles accelerated by the termination shock.

    Second, the telescope can effectively take around 40,000 images per second. It does this by capturing thousands of radio frequencies at the same time. The frequencies are then separated into individual “images.” Chen told Space.com that in order to see termination shock in action, it was necessary to collect that many images for about 20 minutes.

    “So if you do the math, that’s millions and millions of images [you need] in order to extract the information,” Chen said. “That’s a new capability provided by the upgraded VLA.”

    Chen said the new findings don’t necessarily mean that termination shocks are responsible for accelerating particles in all solar flares. He said he and his colleagues would like to conduct further observations to find out if this is the case in all shocks, or only a subset.

    The termination shock explanation has been part of the “standard” solar-flare theory for years, but there hasn’t been “convincing” observational evidence to back it up, Chen said. Chen’s comment was confirmed by Edward DeLuca, a senior astrophysicist at the Smithsonian Astrophysical Observatory, which is part of the Harvard-Smithsonian Center for Astrophysics (DeLuca works in the same department as Chen, but was not involved with the new research.)

    “[The new result] reveals that we’re on the right track with the standard-flare model,” DeLuca said.

    Look out for powerful particles

    All those NASA satellites studying the sun are not just working to create mesmerizing images; they’re also there to help protect Earth. Solar flares and coronal mass ejections pose a hazard to the planet. The particles they eject can damage satellites and solar panels, and could pose a serious threat to astronauts doing spacewalks outside the International Space Station, on the moon or Mars.

    They can even cause surges in power grids on the ground. In 1989, a CME caused a blackout across the entire province of Quebec, Canada.

    The superfast particles are of particular worry, because their high speeds mean they can penetrate more layers of material than their “slower” counterparts. When those particles penetrate a piece of solid-state equipment, they can cause a “bit flip” — which could not only damage the equipment but also change what it does.

    “If that little flip of the bit means a computer command that normally says, ‘keep taking snapshots of the sun,’ instead says ‘shut down the spacecraft,’ that’s bad,” Young said. “So a lot of times, if there is a large particle event, spacecraft operators will often put their spacecraft into what’s called a ‘safe mode.'”

    That reaction has to happen fast. Light can travel from the sun to the earth in 8 minutes, so the solar energetic particles can reach an orbiting satellite in about 10 to 20 minutes, Young said. Coronal mass ejections leave a little more time, but a delayed response can mean serious consequences.

    For that reason, scientists are trying to get better at predicting when solar flares and CME’s will occur and how intense they will be.

    DeLuca said the new understanding of termination shock will not, most likely, be immediately useful for improving forecasting of solar explosions. But it is a piece of the solar-flare puzzle, and he said it will be incorporated into “next-generation” solar-weather technology and prediction techniques. It’s one more step toward helping humans ride out the solar storm.

    See the full article here .

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  • richardmitnick 2:08 pm on December 23, 2015 Permalink | Reply
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    From PPPL: “Discovering a previously unknown mechanism that halts solar eruptions before they blast into space” 


    December 23, 2015
    John Greenwald

    This solar flare occurred at the peak of the solar cycle in October 2014 with no observed eruptions. PPPL researchers say this is a promising candidate for studying the effect of guide magnetic fields. (Photo by NASA)

    Among the most feared events in space physics are solar eruptions, massive explosions that hurl millions of tons of plasma gas and radiation into space. These outbursts can be deadly: if the first moon-landing mission had encountered one, the intense radiation could have been fatal to the astronauts. And when eruptions reach the magnetic field that surrounds the Earth, the contact can create geomagnetic storms that disrupt cell phone service, damage satellites and knock out power grids.

    NASA is eager to know when an eruption is coming and when what looks like the start of an outburst is just a false alarm. Knowing the difference could affect the timing of future space missions such as journeys to Mars, and show when steps to protect satellites, power systems and other equipment need to be taken.

    At the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL), researchers led by associate research physicist Clayton Myers have identified a mechanism that may halt eruptions before they leave the sun. The finding, reported in the December 24-31 issue of Nature magazine, provides a potentially important way to distinguish the start of explosions from buildups that will fail. This work was supported by the DOE Office of Science.

    Coronal mass ejection

    The violent eruptions, called “coronal mass ejections,” stem from a sudden release of magnetic energy that is stored in the sun’s corona, the outermost layer of the star. This energy is often found in what are called “magnetic flux ropes,” massive arched structures that can twist and turn like earthly twine. When these long-lived structures twist and destabilize, they can either erupt out into the solar system or fail and collapse back toward the sun.

    The researchers found in laboratory experiments that such failures occur when the guide magnetic field — a force that runs along the flux rope — is strong enough to keep the rope from twisting and destabilizing. Under these conditions, the guide field interacts with electric currents in the flux rope to produce a dynamic force that halts the eruptions. PPPL has discovered the importance of this force, called the “toroidal field tension force,” which is missing from existing models of solar eruptions.

    The researchers discovered this importance using the Laboratory’s Magnetic Reconnection Experiment (MRX), the world’s leading device for studying how magnetic fields in plasma converge and violently snap apart. The scientists modified the device to produce both a flux rope, which stores a significant amount of energy that seeks to drive the rope outward, and a “potential magnetic field” like the ones that enclose the rope in the solar corona.

    Potential magnetic field

    This potential magnetic field is composed of magnetic “strapping” and “guide” fields, each of which provides restraining forces. Eruptions burst forth when the restraining forces in the strapping field become too weak to hold the rope down, creating what is called a “torus instability” that shoots plasma into space. The guide field, which reduces the twist in the flux rope, had long been thought to be of secondary importance.

    But the researchers found that the guide field can play an important role in halting eruptions. When the flux rope starts to move outward in the presence of a sufficiently powerful guide field, the plasma undergoes an internal reconfiguration — or “self-organization” — that causes the eruption to lose energy and collapse. “The presence of a substantial guide field should therefore indicate a reduced probability of eruption,” said Myers.

    Solar physicists should thus be on the lookout for guide fields, which can be found in relatively simple reconstructions of the sun’s potential magnetic field. One promising candidate for study is the largest active region in the peak solar cycle that took place in October 2014, which produced many large flares but no observed eruptions. Preliminary analysis of this region shows that a number of these flares were associated with failed eruptions that could have been caused by the mechanism the MRX experiments found.

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    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

  • richardmitnick 9:08 am on October 26, 2015 Permalink | Reply
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    From ESA: “A spooky skyscape to celebrate Halloween” 

    European Space Agency


    B. Jørgensen (http://www.arcticphoto.no/)

    Eerie sheets and ripples of green hang above a deserted rocky landscape in this spooky Space Science Image of the Week. Spikes of neon and emerald seem to form the ominous form of a ghostly celestial eagle, with a sharp beak, bright head and majestic outstretched wings.

    While this photograph may resemble paranormal happenings or alien activity, the dramatic skyscape shown here is actually due to a much more common astronomical event known as a coronal mass ejection, or CME.

    This scene was captured on 24 January 2012 above Grotfjord, Norway, by photographer Bjørn Jørgensen. The day before, the Sun flung a burst of high-speed charged particles – electrons, protons and other ions – out into space. Large CMEs can contain up to a billion tonnes of matter, all streaming through space at speeds of up to 2000 km/s.

    These particles sped towards Earth and some of them became trapped within our planet’s magnetosphere, a region of space in which charged particles are contained by Earth’s magnetic field.

    These particles then began to rain down into our atmosphere, smashing into atoms and molecules of oxygen and nitrogen in the process. These collisions release large amounts of energy in the form of light, painting distinctive colours in the sky.

    The colour depends on the particle hit. The most common colours are the reddish-blue of nitrogen and the red or greenish-yellow hues of atomic and molecular oxygen (as seen here). These colours can mix to produce striking shades of orange, yellow, pink and purple.

    Because of their speed and particle density, CMEs often trigger stunning auroral displays. When the Sun is particularly active it can produce several CMEs per day, dropping to roughly one every five days at lower activity levels. On average, between one and four CMEs hit Earth each month; these are called “Halo CMEs”.

    A flotilla of spacecraft, including the ESA-led SOHO, Proba-2 and Cluster missions, monitor the Sun and its effects on our home planet.


    ESA Proba-2

    ESA Cluster

    See the full article here .

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 2:50 pm on October 5, 2015 Permalink | Reply
    Tags: , , , Coronal Mass Ejections,   

    From AAS NOVA: “A Tornado on the Sun” 


    Amercan Astronomical Society

    5 October 2015
    Susanna Kohler

    SDO/AIA image of a giant tornado that formed on the surface of the Sun. This tornado’s height is four times the diameter of the Earth. [NASA/SDO/AIA; Mghebrishvili et al. 2015]

    On 7 November, 2012 at 08:00 UT, an enormous tornado of plasma rose from the surface of the Sun. It twisted around and around, climbing over the span of 10 hours to a height of 50 megameters — roughly four times the diameter of the Earth! Eventually, this monster tornado became unstable and erupted violently as a coronal mass ejection (CME).

    download the mp4 video here.

    Now, a team of researchers has analyzed this event in an effort to better understand the evolution of giant solar tornadoes like this one.

    Oscillating Axis

    In this study, led by Irakli Mghebrishvili and Teimuraz Zaqarashvili of Ilia State University (Georgia), images taken by the Solar Dynamics Observatory’s Atmospheric Imaging Assembly were used to track the tornado’s motion as it grew, along with a prominence, on the solar surface.


    The team found that as the tornado evolved, there were several intervals during which it moved back and forth quasi-periodically. The authors think these oscillations were due to one of two effects when the tornado was at a steady height: either twisted threads of the tornado were rotating around each other, or a magnetic effect known as “kink waves” caused the tornado to sway back and forth.

    Determining which effect was at work is an important subject of future research, because the structure and magnetic configuration of the tornado has implications for the next stage of this tornado’s evolution: eruption.

    Eruption from Instability

    SDO/AIA 3-channel composite image of the tornado an hour before it erupted in a CME. A coronal cavity has opened above the tornado; the top of the cavity is indicated by an arrow. [NASA/SDO/AIA; Mghebrishvili et al. 2015]

    Thirty hours after its formation, the tornado (and the solar prominence associated with it) erupted as a CME, releasing enormous amounts of energy. In the images from shortly before that moment, the authors observed a cavity open in the solar corona above the tornado. This cavity gradually expanded and rose above the solar limb until the tornado and prominence erupted into the space that had been opened.

    Based on these observations, the authors hypothesize that the eruption could be explained using the following model:

    A tornado and a related solar prominence forms.
    Magnetic field lines within it are gradually twisted by the tornado’s rotation, until the tornado becomes unstable to the kink instability (a magnetic instability).
    The tornado then destabilizes the entire prominence, which expands upwards and erupts into a CME through something known as the “magnetic breakout model.”

    If solar tornadoes such as this one generally cause instabilities of prominences, they could be used to predict when a related CME is about to happen — providing important information for space weather predictions.


    Irakli Mghebrishvili et al 2015 ApJ 810 89. doi:10.1088/0004-637X/810/2/89

    See the full article here .

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  • richardmitnick 2:51 pm on September 12, 2014 Permalink | Reply
    Tags: , , , , , Coronal Mass Ejections, ,   

    From SPACE.com: ” Solar Storms Are Bombarding Earth Now, Amped-up Auroras Possible” 

    space-dot-com logo


    Two waves of solar material blown out by powerful sun eruptions this week are hitting the Earth now, and could amplify the aurora displays for observers in northern regions.

    Images of the aurora australis and aurora borealis from around the world, including those with rarer red and blue lights

    Scientists with NOAA’s Space Weather Prediction Center in Boulder, Colorado, expected the first wave of solar flare particles — unleashed by a so-called coronal mass ejection, or CME, on Monday (Sept. 8) — to reach Earth Thursday night (Sept. 11). A second wave, this one caused by a massive solar flare on Wednesday, is due to arrive between Friday and early Saturday.

    NASA Captures Image of M1 Coronal Mass Ejection April 18, 2012

    On August 31, 2012 a long prominence/filament of solar material that had been hovering in the Sun’s atmosphere, the corona, erupted out into space at 4:36 p.m. EDT

    “We do expect these storm levels to cause significant auroral displays across much of the northern U.S. on Friday night,” SWPC Director Thomas Berger told reporters on Thursday. “With clear skies currently forecast for much of these regions, this could be a good opportunity for auroral sightings.”

    The enhanced auroras would likely be most visible across the northern tier U.S. states, along the U.S.-Canada border, as well as in New England, added SWPC program coordinator William Murtagh. Clear, dark skies far from city light pollution are vital to observe any auroras.

    The first of the two solar storm waves reached Earth late Thursday right on time, space weather center officials wrote in an update late Thursday. Also on Thursday, NASA released a new video of the X1.6 solar flare from its sun-watching Solar Dynamics Observatory, showing the event in two different wavelengths.

    Coronal mass ejections are powerful eruptions of super-hot plasma than can be blown out from the sun during major solar flares. This week, the an active sunspot known as AR2158 sun fired off a moderate M4.6 solar flare on Monday, followed by a much more powerful X1.6-class flare on Wednesday, Sept. 10. X-class flares are the most powerful flares the sun experiences.

    Sunspot AR2158 is about the size of between 10 and 20 Earths, but appears to be in the process of breaking up, Berger said. The huge X1.6 solar flare may have been its swan song as it breaks down, he added.

    This NASA image shows the active sunspot AR2158, which unleashed a massive X1.6 solar flare on Sept. 10, 2014, as it appeared on Sept. 8, when it fired off a moderate M4.6 solar flare. On the right, Jupiter and Earth are superimposed to give a sense of the sunspot’s size. Credit: NASA Solar Dynamics Observatory (Little SDO)

    The two solar flares this week were accompanied by coronal mass ejections, and both were aimed at Earth. When directly aimed at Earth, the most powerful solar flares — events stronger than the X1.6 storm on Wednesday — can pose a danger to satellites and astronauts in space, and interfere with communication, navigation and even power distribution surfaces on the Earth’s surface.

    Berger said that the two CMEs from this week’s solar storms could cause some radio and GPS navigation system hiccups, as well as voltage irregularities in power grids of the northern United States, but nothing too extreme.

    “We don’t expect any unmanageable impacts to national infrastructure from these solar events at this time, but we are watching these events closely,” Berger said.

    The huge X1.6-class solar flare is seen erupting from the sun in this three-wavelength composite image captured by NASA’s Solar Dynamics Obervatory on Sept. 10, 2014. The solar flare occurred at 1:45 p.m. ET. Credit: NASA Solar Dynamics Observatory (Little SDO)

    Berger did say that it is fairly rare for two significant coronal mass ejections to hit Earth head-on at nearly the same time. A minor radiation storm was detected from the solar flares, as well as temporary radio blackouts, space weather officials said.

    Space weather officials did say that the most intriguing aspect of this week’s solar flares are their potential for boosting this weekend’s northern lights displays.

    When charged particles from solar storms reach Earth, they are funneled to the polar regions by the planet’s magnetic field and can great so-called geomagnetic storms.

    A minor G1-class storm is underway now, with levels expected to rise to a potentially strong G3-class by Saturday evening, Berger said.

    When solar particles collide with the Earth’s upper atmosphere, they let create a glow that can be visible from the ground as auroral light. In the northern regions of Earth, this glow is known as the aurora borealis, or northern lights. In the south, it is called the aurora australis, or southern lights. Significant solar flares can amplify those displays into dazzling dances of ethereal light.

    See the full article, with videos, here.

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  • richardmitnick 1:46 pm on August 28, 2014 Permalink | Reply
    Tags: , , , Coronal Mass Ejections, , , Solar Storms   

    From NASA/Goddard: “Researchers Use NASA and Other Data to Look Into the Heart of a Solar Storm” 

    NASA Goddard Banner

    August 28, 2014

    Karen C. Fox
    NASA’s Goddard Space Flight Center, Greenbelt, Maryland

    A space weather storm from the sun engulfed our planet on Jan. 21, 2005. The event got its start on Jan. 20, when a cloud of solar material, a coronal mass ejection or CME, burst off the sun and headed toward Earth. When it arrived at our planet, the ring current and radiation belts surrounding Earth swelled with extra particles, while the aurora persisted for six hours. Both of these are usually signs of a very large storm – indeed, this was one of the largest outpouring of solar protons ever monitored from the sun. But the storm barely affected the magnetic fields around Earth – disturbances in these fields can affect power grids on the ground, a potential space weather effect keenly watched for by a society so dependent on electricity.

    A filament of cold dense solar material moved toward the front of a Jan. 20, 2005, coronal mass ejection, which led to an unusually large amount of solar material funneling into near-Earth space during a Jan. 21 solar storm.
    CreditJanet Kozyra

    Twelve spacecraft in Earth’s magnetosphere – in addition to other missions — helped scientists better observe and understand an unusual January 2005 solar storm. The four Cluster spacecraft were in the solar wind, directly upstream of Earth. Picture not to scale.
    Image Credit: ESA

    Janet Kozyra, a space scientist at the University of Michigan in Ann Arbor, thought this intriguing combination of a simultaneously weak and strong solar storm deserved further scrutiny. In an effort to better understand — and some day forecast — such storms and their potential effects on human technology, an unusual event like this can help researchers understand just what aspects of a CME lead to what effects near Earth.

    “There were features appearing that we generally only see during extreme space weather events, when by other measures the storm was moderate,” said Kozyra. “We wanted to look at it holistically, much like terrestrial weather researchers do with extreme weather. We took every single piece of data that we could find on the solar storm and put it together to see what was going on.”

    With observations collected from ground-based networks and 20 different satellites, Kozyra and a group of colleagues, each an expert in different aspects of the data or models, found that the CME contained a rare piece of dense solar filament material. This filament coupled with an unusually fast speed led to the large amount of solar material observed. A fortuitous magnetic geometry, however, softened the blow, leading to reduced magnetic effects. These results were published in the Aug. 14, 2014, issue of Journal of Geophysical Research, Space Physics.

    The researchers gathered data from spacecraft orbiting in Earth’s ionosphere, which extends up to 600 miles above the planet’s surface, and satellites above that, orbiting through the heart of Earth’s magnetic environment, the magnetosphere. The massive amount of data was then incorporated into a variety of models developed at the University of Michigan’s Center for Space Environment Modeling, which are housed at the Community Coordinated Modeling Center at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, a facility dedicated to providing comprehensive access to space weather models.

    With the models in hand, the team could put together the story of this particular solar storm. It began with the CME on Jan. 20, 2005. The European Space Agency and NASA’s Solar and Heliospheric Observatory, or SOHO, captured images of the CME.


    At their simplest, CMEs look like a magnetic bubble with material around the outside. In this case, there was an additional line of colder, denser solar material – an electrically charged gas called plasma – inside called a solar filament. Solar filaments are ribbons of dense plasma supported in the sun’s outer atmosphere – the corona — by strong magnetic fields. Filament material is 100 times denser and 100 times cooler than the surrounding atmosphere. When the supporting magnetic fields erupt, the filaments are caught up in the explosive release that forms the CME. Despite observations that the majority of eruptions like this involve solar filaments, the filaments are rarely identified in disturbances that reach Earth. Why this might be, is a mystery – but it means that the presence of the solar filament in this particular event is a rare sighting.

    Subsequent observations of the CME showed it to be particularly fast, with a velocity that peaked at around 1800 miles per second before slowing to 600 miles per second as it approached Earth. Just how many CMEs have filaments or how the geometry of such filaments change as they move toward Earth is not precisely known. In this case, however, it seems that the dense filament sped forward, past the leading edge of the CME, so as it slammed into the magnetosphere, it delivered an extra big dose of energetic particles into near-Earth space.

    What happened next was observed by a flotilla of Earth-orbiting scientific satellites, including NASA’s IMAGE, FAST and TIMED missions, the joint European Space Agency, or ESA, and NASA’s Cluster, the NASA and ESA’s Geotail, the Chinese and ESA’s Double Star-1; other spacecraft 1 million miles closer to the sun including SOHO and NASA’s Advanced Composition Explorer, Wind various other spacecraft; as well as the National Science Foundation-supported ground-based SuperDARN radar network. At the time Cluster was in the solar wind directly upstream of Earth. Meanwhile, Double Star-1 was passing from the outer region of the planet’s magnetic field and entering the magnetosphere. This enabled it to observe the entry of the solar filament material as it crossed into near-Earth space.

    “Within one hour of the impact, a cold, dense plasma sheet formed out of the filament material,” said Kozyra. “High density material continued to move through the magnetosphere for the entire six hours of the filament’s passage.”

    Despite the intense amount of plasma carried by the CME, it still lacked a key component of a super storm. The magnetic fields embedded in this CME generally pointed toward Earth’s north pole, just as Earth’s own magnetic fields do. This configuration causes far fewer disruptions to our planet’s system than when the CME’s fields point southward. When pointing south, the CME’s fields clash with Earth’s, peeling them back and setting off magnetic perturbations that cascade through the magnetosphere.

    The magnetic field orientation is what kept this solar storm to low levels. On the other hand, the extra solar material from the filament catalyzed long-term aurora over the poles and enhanced the particle filled radiation belts around Earth, characteristic of a larger storm.

    “This event, with its unusual combination of space weather effects really demonstrates why it’s important to look at the entire system, not just individual elements,” said Kozyra. “Only by using all of this data, by watching the event from the beginning to the end, can we begin to understand all the different facets of an extreme storm like this.”

    Understanding what created the facets of this particular 2005 storm adds to a much larger body of knowledge about how different kinds of CMEs can affect us here at Earth. By knowing what factors lead to the total strength of a storm, we can better learn to predict what the sun is sending our way.

    A coronal mass ejection on Jan. 20, 2005, produced an extreme amount of solar particles, seen as white static in this imagery from ESA/NASA’s Solar and Heliospheric Observatory. Closer to Earth, it created a solar storm with an unusual combination of strong and weak effects.
    Image Credit: ESA/NASA/SOHO

    This work was supported by NASA’s Heliophysics Division, in combination with the National Science Foundation’s Division of Atmospheric and Geospace Sciences.

    See the full article here.

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

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


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