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  • richardmitnick 9:32 am on March 8, 2019 Permalink | Reply
    Tags: , , , Bernhard Kliem of the University of Potsdam in Germany and his colleagues scrutinized a CME recorded on May 13 2013 by NASA’s Solar Dynamics Observatory, But it was unclear how coronal mass ejections or CMEs get started, CME's - Coronal Mass Ejections, , , Over about half an hour the blobs shot upward and merged into a large flux rope which briefly arced over the solar surface before erupting into space., , Solar plasma eruptions are the sum of many parts a new look at a 2013 coronal mass ejection shows, , Solar scientists have long wondered what drives big bursts of plasma called coronal mass ejections. New analysis of an old eruption suggests the driving force might be merging magnetic blobs, That quick growth supports the idea that CMEs grow through magnetic reconnection, That speedy setup might make it more difficult to predict when CMEs are about to occur, The team led by Tingyu Gou and Rui Liu of the University of Science and Technology of China in Hefei, They found that before it erupted a vertical sheet of plasma split into blobs marking breaking and merging magnetic field lines   

    From Science News: “Merging magnetic blobs fuel the sun’s huge plasma eruptions” 

    From Science News

    March 7, 2019
    Lisa Grossman

    Before coronal mass ejections, plasma shoots up, breaks apart and then comes together again.

    1
    BURSTING WITH PLASMA Solar scientists have long wondered what drives big bursts of plasma called coronal mass ejections. New analysis of an old eruption suggests the driving force might be merging magnetic blobs.

    Solar plasma eruptions are the sum of many parts, a new look at a 2013 coronal mass ejection shows.

    These bright, energetic bursts happen when loops of magnetism in the sun’s wispy atmosphere, or corona, suddenly snap and send plasma and charged particles hurtling through space (SN Online: 8/16/17).

    But it was unclear how coronal mass ejections, or CMEs, get started. One theory suggests that a twisted tube of magnetic field lines called a flux rope hangs out on the solar surface for hours or days before a sudden perturbation sends it expanding off the solar surface.

    Another idea is that the sun’s magnetic field lines are forced so close together that the lines break and recombine with each other. The energy of that magnetic reconnection forms a short-lived flux rope that quickly erupts.

    “We do not know which comes first,” the flux rope or the reconnection, says solar physicist Bernhard Kliem of the University of Potsdam in Germany.

    Kliem and his colleagues scrutinized a CME recorded on May 13, 2013, by NASA’s Solar Dynamics Observatory.

    NASA/SDO

    They found that before it erupted, a vertical sheet of plasma split into blobs, marking breaking and merging magnetic field lines. Over about half an hour, the blobs shot upward and merged into a large flux rope, which briefly arced over the solar surface before erupting into space. That quick growth supports the idea that CMEs grow through magnetic reconnection, the team, led by Tingyu Gou and Rui Liu of the University of Science and Technology of China in Hefei, reports March 6 in Science Advances.

    “This was actually surprising, that this reconnection was rather fast,” Kliem says. That speedy setup might make it more difficult to predict when CMEs are about to occur. That’s too bad because, when aimed at Earth, these bursts cause auroras and can knock out power grids and damage satellites.


    A STAR’S CME IS BORN The sun’s coronal mass ejections seem to result from many small plasma blobs combining. In this video, enhanced data from NASA’s Solar Dynamics Observatory shows a vertical sheet of plasma suddenly break into blobs at about 17 seconds. Shortly after, the blobs rearrange themselves into a loop, and the loop bursts off the sun’s surface. At 30 seconds, more distant observations from the SOHO telescope show the CME’s progress. (A second, unrelated CME erupts off the right side of the sun near the video’s end.)

    See the full article here .


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  • richardmitnick 9:04 am on March 7, 2019 Permalink | Reply
    Tags: , , , CME's - Coronal Mass Ejections, , , ,   

    From COSMOS Magazine: “Mechanics of coronal mass ejections revealed” 

    Cosmos Magazine bloc

    From COSMOS Magazine

    07 March 2019
    Lauren Fuge

    1
    A coronal mass ejection captured by NASA’s Solar Dynamics Observatory in September, 2017. NASA/SDO.

    NASA/SDO

    An international team of astronomers has untangled new insight into the birth of coronal mass ejections, the most massive and destructive explosions from the sun.

    In a paper published in the journal Science Advances, a team led by Tingyu Gou from the University of Science and Technology of China was able to clearly observe the onset and evolution of a major solar eruption for the first time.

    From a distance the sun seems benevolent and life-giving, but on closer inspection it is seething with powerful fury. Its outer layer – the corona – is a hot and wildly energetic place that constantly sends out streams of charged particles in great gusts of solar wind.

    It also emits localised flashes known as flares, as well as enormous explosions of billions of tons of magnetised plasma called coronal mass ejections (CMEs).

    These eruptions could potentially have a big effect on Earth. CMEs can damage satellite electronics, kill astronauts on space walks, and cause magnetic storms that can disrupt electricity grids.

    Studying CMEs is key to improving the capability to forecast them, and yet, for decades, their origin and evolution have remained elusive.

    “The underlying physics is a disruption of the coronal magnetic field,” explains Bernhard Kliem, co-author on the paper, from the University of Potsdam in Germany.

    Such a disruption allows an expanding bubble of plasma – a CME – to build up, driving it and the magnetic field upwards. The “bubble” can tear off and erupt, often accompanied by solar flares.

    The magnetic field lines then fall back and combine with neighbouring lines to form a less-stressed field, creating the beautiful loops seen in many UV and X-ray images of the sun.

    “This breaking and re-closing process is called magnetic reconnection, and it is of great interest in plasma physics, astrophysics, and space physics,” says Kliem.

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

    NASA TRACE spacecraft (1998-2010)

    But the reason why the coronal magnetic field is disturbed at all is a matter of continuing debate.

    “To many, an instability of the magnetic field is the primary reason,” says Kliem. “This requires the magnetic field to form a twisted flux tube, known as magnetic flux rope, where the energy to be released in the eruption can be stored.”

    The theory holds that turbulence causes the magnetic flux ropes to become tangled and unstable, and if they suddenly rearrange themselves in the process of magnetic reconnection, they can release the trapped energy and trigger a CME.

    Others in the field think that it’s the other way around – magnetic reconnection is the trigger that forms the flux rope in the first place.

    It’s a tricky question to tease out because flux ropes and reconnection are so intertwined. Recent studies [Nature] even suggest that there’s another layer of complexity: smaller magnetic loops called mini flux ropes, or plasmoids, which continuously form in a fractal-like fashion and may have a cascading influence on bigger events like a CME.

    To get a better handle on this complex process, the team observed the evolution of a CME that erupted on May 13, 2013. By combining multi-wavelength data from NASA’s Solar Dynamics Observatory (SDO) with modern analysis techniques, they were able to determine the correct sequence of events: that a magnetic reconnection in the solar corona formed the flux rope, which then became unstable and erupted.

    Specifically, they found that the CME bubble continuously evolved from mini flux ropes, bridging the gap between micro- and macro-scale dynamics and thus illuminating a complete evolutionary path of CMEs.

    The next step, Kliem says, is to understand another important phenomenon in the eruption process: a thin, elongated structure known as a “current sheet”, in which the mini flux ropes were formed.

    “We need to study when and where the coronal magnetic field forms such current sheets that can build up a flux rope, which then, in turn, can erupt to drive a solar eruption,” he concludes.

    See the full article here .


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  • richardmitnick 11:21 am on February 19, 2019 Permalink | Reply
    Tags: 24 radio telescopes from the Low Frequency Array (LOFAR), , , , CME's - Coronal Mass Ejections, , , University of Helsinki   

    From University of Helsinki via COSMOS: “Observations reveal new ‘shape’ for coronal mass ejections” 

    From University of Helsinki

    via

    Cosmos Magazine bloc

    COSMOS Magazine

    19 February 2019
    Phil Dooley

    Radiation signatures produced by giant solar storms more complex than previously thought.

    1
    An artist’s impression of a coronal mass ejection. LV4260/Getty Images

    Astronomers using one of the most sensitive arrays of radio telescopes in the world have caught a huge storm erupting on the sun and observed material flung from it at more than 3000 kilometres a second, a massive shockwave and phenomena known as herringbones.

    In the journal Nature Astronomy, Diana Morosan from the University of Helsinki in Finland and her colleagues report detailed observations of the huge storm, a magnetic eruption known as a coronal mass ejection (CME).

    Unlike the herringbones a biologist might find while dissecting, well, a herring, the team found a data-based version while dissecting the radio waves emitted during the violent event.

    The shape of the fish skeleton emerged when they plotted the frequencies of radio waves as the CME evolved. The spine is a band of emission at a constant frequency, while the vertical offshoot “bones” on either side were sudden short bursts of radiation at a much wider range of frequencies.

    Herringbones have been found in the sun’s radio-wave entrails before, but this is the first time that such a sensitive array of radio telescopes has recorded them. The detailed data enabled Morosan and colleagues for the first time to pin down the origin of the radiation bursts.

    To their surprise, the bones were being created in three different locations, on the sides of the CME.

    “I was very excited when I first saw the results, I didn’t know what to make of them,” Morosan says.

    As the CME erupted, the astronomers were already monitoring the sun, using 24 radio telescopes from the Low Frequency Array (LOFAR) distributed around an area of about 320 hectares near the village of Exloo in The Netherlands.

    ASTRON LOFAR Radio Antenna Bank, Netherlands

    SKA LOFAR core (“superterp”) near Exloo, Netherlands

    “We had seen this really complicated active region – really big ugly sunspots, that had already produced three X-class flares, so we thought we should point LOFAR at it and see if it produces any other eruptions,” explains Morosan.

    A last minute request to the LOFAR director was rewarded with an eight-hour slot on the following Sunday, during which the active region erupted again, emitting X-rays so intense that it was classified as an X-class flare, the most extreme category.

    Flares are caused by turbulence in the plasma that makes up the sun. Plasma is gas that is so hot that the electrons begin to be stripped from the atoms, forming a mixture of charged particles. As it swirls around in the sun the charged particles create magnetic fields. When the turbulence rises the magnetic field lines can get contorted and unstable, a little like a tightly coiled and tangled spring.

    Sometimes the tangled magnetic field suddenly rearranges itself in a violent event called magnetic reconnection, a bit like a coiled spring breaking and thus releasing a lot of trapped energy. It is this energy that powers the flare and propels the plasma out into space to form the CME.

    “The CME is still connected to the solar atmosphere via the magnetic field, so it looks like a giant bubble expanding out,” Morosan says.

    The extreme energy in the CME – the second largest during the sun’s most recent 11-year cycle – accelerated matter away from the sun’s surface to over 3000 kilometres per second, or 1% of the speed of light.

    Because it was so fast the CME formed a shockwave as it travelled through the heliosphere – the atmosphere around the sun. Similar to the sonic boom created by a supersonic aircraft, the shockwave accelerated electrons to extreme speeds and caused them to emit radio waves that Morosan and her colleagues recorded.

    The exact frequency of the radio waves emitted by the electrons depends on the density of their environment. Close to the sun the photosphere density is higher, which creates higher frequency radio waves. The further the electrons are from the sun the lower the frequency of the radio emission.

    So the shape of the herringbones as a plot of frequencies shows where the accelerated electrons are in the sun’s atmosphere.

    The spine represents a constant frequency emission originating from electrons trapped in the shockwave. These escape in bursts from the shock and get funneled along the magnetic field lines on the surface of the CME bubble.

    Some bursts of electrons are funneled back towards the sun. These are the herringbone offshoots to higher frequency, while the ones that get funneled the other way, out into space, create offshoots to lower frequency.

    The sensitivity of the array of radio telescopes allowed the team to clearly identify three sources of herringbone radiation, all of them on the flanks of the CME, not at the front of it, as had been proposed.

    However, the success of the observation was cut short because the timeslot on the LOFAR array came to its end, while the CME was still in full swing.

    “We don’t know what happened after the flare peaked,” Morosan notes. “So we were lucky, and unlucky!”

    See the full article here .

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    U Helsinki main building

    University of Helsinki, Viikki campus focusing on biological sciences

    The University of Helsinki (Finnish: Helsingin yliopisto, Swedish: Helsingfors universitet, Latin: Universitas Helsingiensis, abbreviated UH) is a university located in Helsinki, Finland since 1829, but was founded in the city of Turku (in Swedish Åbo) in 1640 as the Royal Academy of Åbo, at that time part of the Swedish Empire. It is the oldest and largest university in Finland with the widest range of disciplines available. Around 36,500 students are currently enrolled in the degree programs of the university spread across 11 faculties and 11 research institutes.

    As of 1 August 2005, the university complies with the harmonized structure of the Europe-wide Bologna Process and offers Bachelor, Master, Licenciate, and Doctoral degrees. Admission to degree programmes is usually determined by entrance examinations, in the case of bachelor’s degrees, and by prior degree results, in the case of master and postgraduate degrees. Entrance is particularly selective (circa 15% of the yearly applicants are admitted). It has been ranked a top 100 university in the world according to the 2016 ARWU, QS and THE rankings.

    The university is bilingual, with teaching by law provided both in Finnish and Swedish. Since Swedish, albeit an official language of Finland, is a minority language, Finnish is by far the dominating language at the university. Teaching in English is extensive throughout the university at Master, Licentiate, and Doctoral levels, making it a de facto third language of instruction.

    Remaining true to its traditionally strong Humboldtian ethos, the University of Helsinki places heavy emphasis on high-quality teaching and research of a top international standard. It is a member of various prominent international university networks, such as Europaeum, UNICA, the Utrecht Network, and is a founding member of the League of European Research Universities.

     
  • richardmitnick 10:50 am on August 23, 2018 Permalink | Reply
    Tags: , Carrington Event of 1859, CME's - Coronal Mass Ejections, Earth’s protective magnetic field has undergone relatively rapid shifts in the past, , , Researchers find fast flip in Earth’s magnetic field   

    From ANU via EarthSky: “Researchers find fast flip in Earth’s magnetic field” 

    ANU Australian National University Bloc

    Australian National University

    via

    1

    EarthSky

    August 22, 2018
    Deborah Byrd

    By studying the magnetic record left behind in earthly rocks, researchers found a magnetic field reversal – where magnetic north became magnetic south – lasting only 2 centuries.

    1
    Artist’s concept of Earth’s magnetic field, which surrounds and protects our planet, and which sometimes flips. Image via NASA/Peter Reid, University of Edinburgh/astrobio.net.

    A research team led by scientists in Taiwan and China announced on August 21, 2018, that Earth’s protective magnetic field has undergone relatively rapid shifts in the past, including one lasting just two centuries.

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

    That’s fast in contrast to the thousands of years thought to be needed for a magnetic pole reversal, an event whereby magnetic south becomes magnetic north and vice versa. Such an event might leave Earth with a substantially reduced magnetic field for some unknown period of time, exposing our world to dangerous effects from the sun. If it occurred in today’s world of ubiquitous electric power and global interconnected communications, a reduced magnetic field could cost us trillions of dollars. The peer-reviewed journal Proceedings of the National Academy of Sciences published this new work on August 20.

    Co-author Andrew Roberts of Australian National University (ANU) said in a statement that Earth’s magnetic strength could decrease by about 90 percent during a magnetic reversal. He said:

    “Earth’s magnetic field, which has existed for at least 3.45 billion years, provides a shield from the direct impact of solar radiation.
    Even with Earth’s strong magnetic field today, we’re still susceptible to solar storms that can damage our electricity-based society.”

    Roberts contributed to the study via precise magnetic analysis and radiometric dating of a stalagmite from a cave in southwestern China. Via this study, he and his colleagues added to the known paleomagnetic record from 107,000 to 91,000 years ago. A close look at this 16,000-year-long data set revealed that, during this period, the polarity flipped within only a couple of centuries some 98,000 years ago. Roberts commented:

    “The record provides important insights into ancient magnetic field behavior, which has turned out to vary much more rapidly than previously thought.”

    As the researchers described it, the flip was nearly 30 times faster than a generally accepted time required for polarity flips and 10 times faster than the fastest known rate of change.

    Magnetic pole reversals are natural events, and earthly life has evolved for billions of years with them going on in the background. What’s different today is that humans have developed technologies susceptible to events on the sun. To give you an idea of how powerful the sun is, watch a bit of the video below, showing a July 19, 2012, eruption on the sun. The eruption produced a moderately powerful solar flare, exploding on the sun’s lower right hand limb, sending out light and radiation. It then produced a coronal mass ejection, or CME, which shot off to the right out into space. It’s the CMEs that are so dangerous to earthly technologies.

    As do so many discussions of this kind, the ANU statement about the new work harked back to what’s called the Carrington Event of 1859. It’s named for the British astronomer Richard Carrington, who spotted the preceding solar flare. It’s the largest-ever solar super-storm on record (but, remember, our human record doesn’t last very long in contrast to the millions of years of human existence). According to an article in Physics World in 2014:

    “This massive CME released … the equivalent to 10 billion Hiroshima bombs exploding at the same time. [It] hurled around a trillion kilograms [a million tons] of charged particles towards the Earth at speeds of up to 3,000 km/s [1900 miles/sec]. Its impact on the human population, though, was relatively benign as our electronic infrastructure at the time amounted to no more than about 200,000 kilometers [120,000 miles] of telegraph lines.”

    The Carrington Event took place long before our vast electric power grids and satellites in orbit. A more recent event – the biggest earthly effect from a solar storm in living memory – happened on March 13, 1989. A storm on the sun that day caused auroras that could be seen as far south as Florida and Texas. It caused some satellites in orbit to lose control temporarily, and – most significantly – it sparked an electrical collapse of the Hydro-Québec power grid, causing a widespread electrical blackout for about nine hours.

    And that is the issue. Events on the sun, and their accompanying CMEs, aren’t harmful to earthly life. After all, life on Earth has evolved for billions of years, as occasional solar super-storms took place. But these space weather events are harmful to human technologies, such as satellites and electrical grids.

    3
    Boom! A CME lifts off from the sun’s surface to space. This image was obtained in 2001 by the Solar and Heliospheric Observatory (SOHO) and is via ESA and NASA.

    ESA/NASA SOHO


    ESA/NASA SOHO

    For the most part, our magnetic field protects us. With Earth’s magnetic field in place, you would need an exceedingly strong solar flare to create a Carrington Event. But if Earth’s magnetic field were diminished due to an ongoing magnetic field reversal, our technologies would be left vulnerable. Roberts commented:

    “Hopefully such an event is a long way in the future and we can develop future technologies to avoid huge damage, where possible, from such events.”

    I think we can and will! What do you think?

    4
    Northern lights (aurora borealis) seen on Earth from orbit. The same events on the sun that cause these beautiful auroras have the potential to damage earthly electrical grids and satellites in orbit. Image via NASA/ESA.

    Bottom line: Researchers have learned that magnetic field reversals on Earth can happen on a relatively fast timescale. They have evidence for one that took place over only two centuries. Prior to this work, it was thought that magnetic reversals took thousands of years.

    ANU Campus

    ANU is a world-leading university in Australia’s capital city, Canberra. Our location points to our unique history, ties to the Australian Government and special standing as a resource for the Australian people.

    Our focus on research as an asset, and an approach to education, ensures our graduates are in demand the world-over for their abilities to understand, and apply vision and creativity to addressing complex contemporary challenges.

    See the full article here .


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    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 11:41 am on April 25, 2018 Permalink | Reply
    Tags: , , , , CME's - Coronal Mass Ejections, , ,   

    From Eos: “Capturing Structural Changes of Solar Blasts en Route to Earth” 

    AGU
    Eos news bloc

    Eos

    4.25.18
    Sarah Stanley

    Comparison of magnetic field structures for 20 coronal mass ejections at eruption versus Earth arrival highlights the importance of tracking structural evolution to refine space weather predictions.

    1
    Coronal mass ejections erupt when flux ropes—the blue loops seen here—lose stability, resulting in a blast of plasma away from the Sun. New research [AGU Space Weather] emphasizes the importance of changes in the magnetic field structure of flux ropes between eruption of plasma blasts and their arrival at Earth. Credit: NASA/Goddard Space Flight Center/SDO, CC BY 2.0

    NASA/SDO

    Huge clouds of plasma periodically erupt from the Sun in coronal mass ejections. The magnetic field structure of each blast can help determine whether it might endanger spacecraft, power grids, and other human infrastructure. New research by Palmerio et al. highlights the importance of detecting any changes in the magnetic field structure of a coronal mass ejection as it races toward Earth.

    Coronal mass ejections often erupt in the form of a flux rope—a twisted, helical magnetic field structure that extends outward from the Sun. A flux rope can come in a variety of types that depend on the direction of the magnetic field axis and whether its helical component curves to the left or right. While the direction of the helical curve remains unchanged, the axis can alter direction after eruption from the Sun.

    In the new study, the researchers analyzed observations of 20 different coronal mass ejections, comparing their flux rope structure at eruption to their structure once they reached satellites near Earth. They used a variety of satellite and ground-based observations to reconstruct the eruption structures, and they directly observed structures close to Earth as the plasma blasts washed over NASA’s Wind spacecraft.

    NASA Wind Spacecraft

    The analysis showed that between Sun eruption and Earth arrival, flux rope structure changed axis direction by more than 90° for 7 of the 20 coronal mass ejections. The rest of the blasts had an axis rotation of less than 90°, with five changing by less than 30° after eruption.

    These results highlight the importance of capturing posteruption changes in flux rope magnetic field structures of coronal mass ejections to refine space weather predictions. Such rotations can result from a variety of causes, including deformations in the Sun’s corona and interaction with other coronal mass ejections.

    However, capturing these changes remains a challenge. Reconstructions of flux rope structure from direct spacecraft observations may vary depending on which reconstruction technique is used. In addition, such observations depend on the spacecraft’s particular path through a coronal mass ejection, which might not give an accurate picture of the overall structure.

    And although posteruption structural changes are important, the researchers emphasize that the flux rope structure of a coronal mass ejection at eruption is still a good approximation for its structure upon Earth arrival and serves as a key input for space weather forecasting models.

    See the full article here .

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

     
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