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  • richardmitnick 10:25 am on March 23, 2019 Permalink | Reply
    Tags: , , , , , Solar Flares Waves Jets and Ejections, Solar research   

    From AAS NOVA: “Flares, Waves, Jets, and Ejections” 

    AASNOVA

    From AAS NOVA

    22 March 2019
    Susanna Kohler

    1
    Solar Dynamics Observatory images at 171 Å of a blowout jet erupting in the solar corona on 9 Mar 2011. The dashed white line shows the direction of jet eruption. [SDO/Miao et al. 2018]

    NASA/SDO

    Our Sun often exhibits a roiling surface full of activity. But how do the different types of eruptions and disturbances we see relate to one another? Observations of one explosive jet are helping us to piece together the puzzle.

    Looking for Connections

    2
    A coronal blowout jet captured by the Solar Dynamics Observatory on 9 Mar 2011. [Miao et al. 2018]

    Energy travels through and from the Sun via dozens of different phenomena. We see ultraviolet waves that propagate across the disk, loops and flares of plasma stretching into space, enormous coronal mass ejections that expel material through the solar system, and jets of all different sizes extending from the Sun’s surface and atmospheric layers. A longstanding mission for solar physicists has been to relate these phenomena into a broader picture explaining how energy is released from our closest star.

    3
    Positions of the two STEREO satellites relative to the Sun and the Earth. SDO orbits the Earth. The green arrow shows the eruption direction of the blowout jet. [Miao et al. 2018]

    An Enlightening Explosion

    On 9 March 2011, a coronal blowout jet erupted from the Sun’s surface. Three spacecraft were on hand to watch: the Solar Dynamics Observatory, STEREO Ahead, and STEREO Behind.

    NASA/STEREO spacecraft

    These observatories were each located roughly 90° from each other, providing a view of the Sun’s surface from multiple angles at the moment of the explosion.

    What did they these observatories see?

    The flare
    The eruption of the blowout jet — which lasted ~21 minutes — was accompanied by a class 9.4 solar flare.
    The wave
    Shortly after the jet launch, an arc-shaped extreme ultraviolet (EUV) wave appeared on the southeastern side of the jet. This wave lasted ~4 minutes and propagated away from the site of the jet.
    The jet
    The jet itself contains both bright and dark material. The dark material appears to be due to a mini-filament — a thread of cool, dense gas suspended above the Sun’s surface by magnetic fields — that erupted in the jet base.
    The coronal mass ejection
    The two STEREO spacecraft captured what happened on large scales in the outer corona of the Sun, revealing an explosive coronal mass ejection spewing matter into space. The ejection consisted of two structures: a jet-like component and a bubble-like component.

    Causal Ties?

    4
    STEREO Ahead (left) and Behind (right) images of the coronal mass ejection in the outer corona. Both a jet-like and a bubble-like component can be seen. [Miao et al. 2018]

    These observations provide an unprecedented look at multiple types of solar activity all occurring simultaneously — and they suggest causal ties between the different phenomena.

    In particular, the authors propose a relation in which the EUV wave was a fast-mode magnetohydrodynamic wave driven by the blowout jet eruption. They also suggest that the jet-like component of the coronal mass ejection is the outer-corona extension of the hot part of the blowout jet body, while the bubble-like component might be associated with the eruption of the mini-filament at the jet base.

    More observations like those of this event are needed to draw definitive conclusions, but this explosion has provided some definite clues about the relationship between different phenomena as the Sun lashes out into its surroundings.

    Bonus

    Watch the propagation of the EUV wave (top video), the eruption of the blowout jet (middle video), and the coronal mass ejections (bottom video) in the clips below. Videos can not be
    Copied and presented here. You can view them at the full article.

    Citation

    “A Blowout Jet Associated with One Obvious Extreme-ultraviolet Wave and One Complicated Coronal Mass Ejection Event,” Y. Miao et al 2018 ApJ 869 39.
    https://iopscience.iop.org/article/10.3847/1538-4357/aaeac1/meta

    See the full article here .


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    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 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, , , , 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 research, 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: , , , , , , , Solar research   

    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 3:57 pm on March 1, 2019 Permalink | Reply
    Tags: "Solving a Stellar Abundance Problem (with a Little Help from Our Oceans)", , Solar research   

    From AAS NOVA: “Solving a Stellar Abundance Problem (with a Little Help from Our Oceans)” 

    AASNOVA

    From AAS NOVA

    1 March 2019
    Kerry Hensley

    1
    What do stellar plasma and saltwater have in common? More than you might think. [NASA/SDO (left) and NOAA (right)]

    NASA/SDO

    When solving mysteries about distant astronomical objects, sometimes it pays to take inspiration from sources closer to home. In today’s example, strange fluid behavior in the Earth’s oceans — combined with a healthy helping of magnetic fields — may provide the answer to a long-standing puzzle about the changing composition of red-giant stars.

    2
    Simulated salt fingers in fluids with decreasing Rayleigh numbers. The Rayleigh number determines whether heat in a system is transferred primarily through diffusion or convection. [Fariarehman]

    A Possibility for Instability

    Red giants undergo a process called dredge-up, during which their outer convective envelopes bring fusion products up to the surface, altering the chemical abundances there. After the dredge-up, surface abundances aren’t expected to change — yet observations show that they continue to evolve long after the dredge-up is complete. What drives this unexpected late-stage mixing in red giants?

    One solution involves an instability called fingering convection. Fingering convection occurs in fluids with vertical gradients in temperature and chemical composition — a setup we see everywhere from the interiors of stars to Earth’s oceans. When the equilibrium of such a fluid is perturbed, the temperature diffuses more quickly than the chemical composition as the system seeks to reestablish equilibrium, triggering a runaway effect.

    What does this look like in practice? Take the ocean as an example. The density of saltwater is determined by temperature and salt content, and warm saltwater often lies atop denser, colder water that is less salty. When a bubble of warmer water is pushed into the colder water beneath it, it cools quickly, but the salt is slow to diffuse outward. The cold, salty water is now denser than the water surrounding it, causing it to sink deeper. As this process continues, salt-rich “fingers” dive downward, eventually depositing the saltier water deep in the ocean.

    The density of the material in stellar interiors depends on temperature, which diffuses rapidly, and chemical composition, which diffuses slowly — the perfect setup for fingering convection.

    3
    Vertical velocity of fluid parcels for three values of the Lorentz force coefficient, HB, which increases as the square of the magnetic field strength. [Harrington & Garaud 2019]

    Peter Harrington and Pascale Garaud (University of California, Santa Cruz) used numerical models to explore the effect of magnetic fields on the rate of convection in stellar interiors.

    In their simulations, the authors apply a vertical background magnetic field of varying strength and randomly impose small perturbations in the temperature and composition. The perturbations grow as the instability takes hold, forming narrow fingers aligned with the magnetic field.

    4
    Evolution of the compositional Nusselt number (a measure of the strength of the vertical compositional transport) over time. Simulations with higher magnetic field strengths saturate more rapidly and reach higher rates of vertical transport. [Harrington & Garaud 2019]

    Implications for Convection

    The authors find that including magnetic fields in their simulations increases the rate of convection, with stronger magnetic fields leading to more rapid convection. For a purely vertical magnetic field of 0.03 Tesla (reasonable for stellar interiors), the convection rate increases by two orders of magnitude — enough to resolve the disagreement between theory and observations.

    Magnetized fingering convection should affect more than just red giants; the authors note that main-sequence stars and white dwarfs should also exhibit this behavior, which needs to be accounted for when interpreting observed surface abundances.

    Citation

    “Enhanced Mixing in Magnetized Fingering Convection, and Implications for Red Giant Branch Stars,” Peter Z. Harrington & Pascale Garaud 2019 ApJL 870 L5.
    https://iopscience.iop.org/article/10.3847/2041-8213/aaf812/meta

    See the full article here .


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    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 2:08 pm on February 23, 2019 Permalink | Reply
    Tags: "New data about spiral waves detected in sunspots", , , , , , Solar research   

    From Instituto de Astrofísica de Canarias – IAC: “New data about spiral waves detected in sunspots” 

    IAC

    From Instituto de Astrofísica de Canarias – IAC

    Jan. 18, 2019

    Tobías Felipe
    tobias@iac.es

    Elena Khomenko
    khomenko@iac.es

    An international study, led by researchers at the IAC, reveal unknown details about the nature of a singular type of oscillatory phenomenon in spiral form detected in sunspots. The research, published in Astronomy & Astrophysics, was carried out using observations with the GREGOR telescope at the Teide Observatory

    KIP telescope GREGOR, on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It is operated by the Instituto de Astrofísica de Canarias

    GREGOR Solar Telescope at Tiede Observatory on Mount Teide at 2,390 metres 7,840 ft, located on Tenerife, Spain. It is operated by the Instituto de Astrofísica de Canarias

    Teide Observatory in Tenerife Spain, home of two 40 cm LCO,telescopes, Altitude 2,390 m (7,840 ft)

    1

    There are many oscillatory phenomena in the Sun which show up from the deepest interior layers to the outermost layers of its atmosphere. The study of these waves is a fundamental problema in solar physics. It is believed that the waves play a key role in the energy balance of our star; they are one of the candidates proposed to explain the high temperatures measured in the chromosphere and the corona of the sun. Also studying the oscillations is a way of characterizing the structure of the Sun using seismological analyses.

    Stars like the Sun show different types of waves. Some are acoustic waves, similar to those on Earth, which allow us to hear sound. However the presence of magnetic fields gives rise to new types of waves with different properties.

    A sudy led by researchers at the IAC and published recently , and picked out as a “highlight” by the journal Astronomy & Astrophysics [A&A above], has studied the propagation of these waves in sunspots and has identified the presence of oscillations in spiral form which start out from the darkest part of the sunspot, called the umbra, and spread into the outer regions, the penumbra. Sunspots are caused by strong concentrations of magnetic field, visible on the solar disc as dark regions, so that these waves can be interpreted as evidence for magneto-acoustic waves which propagate from the interior of the sun out to high layes of the atmosphere, along the direction of the magnetic field.

    This work has used data from the GREGOR telesope, at the Teide Observatory [above], which, with its diameter of 1.5 metres, is the biggest solar telescope in Europe. “ The possibility to use several instruments at a time with the GREGOR has allowed us to obtain the variations in velocity in a two dimensional region, and also a spectropolarimetric map of the sunspot observed” explains Tobías Felipe, the first author of the article, an IAC researcher. “The analysis of the polarization of the light is fundamental for the study of solar magnetic fields; we have been able to work out the geometry of the magnetic field of the sunspot, and relate its orientation to the apparent direction of propagation of the waves”.

    Although previous studies had identified the presence of spiral waves in sunspots, this new study permits the interpretation, for the first time, of these wafes in the contex of a full characterization of the topology of the magnetic field of the sunspot where they are observed. This has allowed us to reject the idea that the spiral is a consequence of the twisting of the magnetic field lines. “The new results suggest that this is the visual pattern of the waves which are propagated upwards from interior layers. Although apparently these waves move in the radial direction, towards the exterior of the spot, what actually happens is that in the outermost regions the front of waves arrive later to the atmospheric layer where they were observed”, says Elena Khomenko, a researcher at the IAC and a co-author of the study.

    This work was carried out in the framework of an international collaboration, in which there was participation by researchers from a German institution (Christoph Kuckein, Leibnitz Institut für Astrophysik, Potsdam) and an Israeli institution ( Irina Thaler, The Hebrew University of Jerusalem).

    See the full article here.


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    The Instituto de Astrofísica de Canarias(IAC) is an international research centre in Spain which comprises:

    The Instituto de Astrofísica, the headquarters, which is in La Laguna (Tenerife).
    The Centro de Astrofísica en La Palma (CALP)
    The Observatorio del Teide (OT), in Izaña (Tenerife).

    These centres, with all the facilities they bring together, make up the European Northern Observatory(ENO).

    The IAC is constituted administratively as a Public Consortium, created by statute in 1982, with involvement from the Spanish Government, the Government of the Canary Islands, the University of La Laguna and Spain’s Science Research Council (CSIC).

    The International Scientific Committee (CCI) manages participation in the observatories by institutions from other countries. A Time Allocation Committee (CAT) allocates the observing time reserved for Spain at the telescopes in the IAC’s observatories.

    The exceptional quality of the sky over the Canaries for astronomical observations is protected by law. The IAC’s Sky Quality Protection Office (OTPC) regulates the application of the law and its Sky Quality Group continuously monitors the parameters that define observing quality at the IAC Observatories.

    The IAC’s research programme includes astrophysical research and technological development projects.

    The IAC is also involved in researcher training, university teaching and outreachactivities.

    The IAC has devoted much energy to developing technology for the design and construction of a large 10.4 metre diameter telescope, the ( Gran Telescopio CANARIAS, GTC), which is sited at the Observatorio del Roque de los Muchachos.

    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

     
  • richardmitnick 10:05 am on February 21, 2019 Permalink | Reply
    Tags: , , , , , , , , Solar research   

    From European Space Agency via Manu Garcia, a friend from IAC: “The limits of the Earth’s atmosphere” 


    From Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    ESA Space For Europe Banner

    From European Space Agency

    20 February, 2019

    Igor Baliukin
    Space Research Institute
    Russian Academy of Science
    Moscow, Russia
    Email: igor.baliukin@gmail.com

    Jean-Loup Bertaux
    Former principal investigator of SWAN
    Laboratoire Atmospheres Milieux, Observations Spatiales (LATMOS)
    Université de Versailles-Saint-Quentin-en-Yvelines, France
    Email: jean-loup.bertaux@latmos.ipsl.fr

    Bernhard Fleck
    SOHO project scientist
    European Space Agency
    Email: bfleck@esa.nascom.nasa.gov

    Markus Bauer
    ESA Science Program Communication Officer
    Tel: +31 71 565 6799
    Mob: +31 61 594 3 954
    Email: markus.bauer@esa.int

    Earth’s atmosphere reaches the Moon and beyond.
    1
    The extent of land geocorona. Where the atmosphere of the Earth merges with outer space, there is a cloud of hydrogen atoms called geocorona. A recent discovery based on observations of the Solar and Heliospheric Observatory ESA / NASA SOHO shows that geocorona extends far beyond the orbit of the Moon, reaching up to 630 000 km above the surface of the Earth, or 50 times the diameter of our planet. Note: The illustration is not to scale. Credit: ESA.

    The most distant region of our atmosphere extends beyond the lunar orbit, up to twice the distance to our natural satellite.

    Thanks to data collected by the Solar and Heliospheric Observatory (SOHO) of ESA / NASA, a recent discovery shows that the gas layer that surrounds the Earth has a radius of 630,000 km, 50 times the diameter of our planet.

    ESA/NASA SOHO

    “The moon orbits inside the Earth’s atmosphere,” says Igor Baliukin, the Russian Space Research Institute and lead author of the paper presenting the results.

    “We were not aware of it until we recover the observations made over two decades ago by SOHO.”

    In the region where the atmosphere merges into the outer space, there is a cloud of hydrogen atoms called “geocorona”. One of the satellite instruments, SWAN [no image available], used its sensors to track the signing of hydrogen and accurately detect how far the limit of the geocorona arrived.

    These observations could be made only at certain times of the year when the Earth and its geocorona were visible instrument.

    In the planets with their exosferas hydrogen, water vapor often seen near the surface. This is what happens on Earth, Mars and Venus.

    Jean-Loup Bertaux as, former principal investigator and co-author SWAN explains: “This is particularly interesting when we look for planets with possible water deposits beyond our solar system.”

    The first telescope on the Moon, deployed in 1972 by the Apollo astronauts 16 mission captured an image reminiscent of Earth wrapped in geocorona bright ultraviolet light.

    “At that time, the astronauts on the lunar surface did not know that they were actually immersed in the outermost layers of the geocorona” says Jean-Loup.

    The Sun interacts with the hydrogen atoms through a specific wavelength of the ultraviolet spectrum, called Lyman alpha, these atoms can absorb and emit. As this type of light is absorbed by Earth’s atmosphere, it can only be observed from space.

    With its cell uptake of hydrogen, the SWAN instrument could measure light selectively Lyman alpha geocorona and discard the hydrogen atoms located in interplanetary space.

    The new study has revealed that sunlight compresses the hydrogen atoms in the geocorona of the day side of the Earth, while producing a denser region on the night side. Hydrogen daytime region of higher density remains rather low, with only 70 atoms per cubic centimeter to 60,000 kilometers from the earth’s surface, and about 0.2 atoms at the distance of the Moon.

    “On Earth we would call it empty, so this extra source of hydrogen is not enough to provide space exploration,” Igor added.

    The good news is that these particles do not pose a threat to space travelers of future manned missions to orbit the moon.

    “There is also ultraviolet radiation associated -we recalls Jean-Loup geocorona Bertaux- since the hydrogen atoms are dispersed in all directions, but the impact on astronauts in orbit would be minimal mole compared to the main radiation source : the Sun”.

    The bad news is that the Earth’s future geocorona could interfere with astronomical observations near the moon.

    As Jean-Loup warns: “Space telescopes that observe the sky in ultraviolet wavelengths to study the chemical composition of stars and galaxies have to take this into account.”

    The power of files.
    2
    Print Artist Solar and Heliospheric Observatory ESA / NASA SOHO, with the Sun seen by the extreme ultraviolet telescope satellite images on September 14 , 1999. Credit: Spacecraft: ESA / Medialab ATG; Sun: ESA / NASA SOHO, CC BY-SA 3.0 IGO

    Launched in December 1995, the space observatory SOHO has more than two decades studying the sun, from inside its core to the outer corona and solar wind. The satellite orbits in the first Lagrange point (L1), about 1.5 million kilometers from Earth toward the sun.

    LaGrange Points map. NASA

    Its position is perfect to watch the geocorona from outside. The SWAN instrument SOHO captured images of the Earth and its atmosphere on three occasions between 1996 and 1998.

    The team of researchers from Jean-Loup and Igor in Russia decided to recover this data set from the files for analysis. These unique of all the geocorona from SOHO views are now shedding new light on Earth’s atmosphere.

    “It is often possible to take advantage of archived data many years and do new science with them -constata Bernhard Fleck, SOHO Project Scientist of ESA-. This finding underscores the value of some data collected over 20 years and the outstanding performance of SOHO “.

    More information:
    The article ” SWAN / SOHO Lyman-alpha mapping: the Hydrogen geocorona extends well beyond the Moon .” I Baliukin et al, is accepted for publication in Journal of Geophysical Research: Space Physics.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 10:43 am on February 20, 2019 Permalink | Reply
    Tags: "Solar Tadpole-Like Jets Seen With NASA’S IRIS Add New Clue to Age-Old Mystery", , , , , , , , Solar research   

    From NASA Goddard Space Flight Center: “Solar Tadpole-Like Jets Seen With NASA’S IRIS Add New Clue to Age-Old Mystery” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Feb. 19, 2019
    Mara Johnson-Groh
    mara.johnson-groh@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    NASA IRIS spacecraft

    Scientists have discovered tadpole-shaped jets coming out of regions with intense magnetic fields on the Sun. Unlike those living on Earth, these “tadpoles” — formally called pseudo-shocks — are made entirely of plasma, the electrically conducting material made of charged particles that account for an estimated 99 percent of the observable universe. The discovery adds a new clue to one of the longest-standing mysteries in astrophysics.

    1
    Anmated images from IRIS show the tadpole-shaped jets containing pseudo-shocks streaking out from the Sun.
    Credits: Abhishek Srivastava IIT (BHU)/Joy Ng, NASA’s Goddard Space Flight Center

    For 150 years scientists have been trying to figure out why the wispy upper atmosphere of the Sun — the corona — is over 200 times hotter than the solar surface. This region, which extends millions of miles, somehow becomes superheated and continually releases highly charged particles, which race across the solar system at supersonic speeds.

    When those particles encounter Earth, they have the potential to harm satellites and astronauts, disrupt telecommunications, and even interfere with power grids during particularly strong events. Understanding how the corona gets so hot can ultimately help us understand the fundamental physics behind what drives these disruptions.

    In recent years, scientists have largely debated two possible explanations for coronal heating: nanoflares and electromagnetic waves. The nanoflare theory proposes bomb-like explosions, which release energy into the solar atmosphere. Siblings to the larger solar flares, they are expected to occur when magnetic field lines explosively reconnect, releasing a surge of hot, charged particles. An alternative theory suggests a type of electromagnetic wave called Alfvén waves might push charged particles into the atmosphere like an ocean wave pushing a surfer. Scientists now think the corona may be heated by a combination of phenomenon like these, instead of a single one alone.

    The new discovery of pseudo-shocks adds another player to that debate. Particularly, it may contribute heat to the corona during specific times, namely when the Sun is active, such as during solar maximums — the most active part of the Sun’s 11-year cycle marked by an increase in sunspots, solar flares and coronal mass ejections.

    The discovery of the solar tadpoles was somewhat fortuitous. When recently analyzing data from NASA’s Interface Region Imaging Spectrograph, or IRIS, scientists noticed unique elongated jets emerging from sunspots ­— cool, magnetically-active regions on the Sun’s surface — and rising 3,000 miles up into the inner corona. The jets, with bulky heads and rarefied tails, looked to the scientists like tadpoles swimming up through the Sun’s layers.

    “We were looking for waves and plasma ejecta, but instead, we noticed these dynamical pseudo-shocks, like disconnected plasma jets, that are not like real shocks but highly energetic to fulfill Sun’s radiative losses,” said Abhishek Srivastava, scientist at the Indian Institute of Technology (BHU) in Varanasi, India, and lead author on the new paper in Nature Astronomy.

    Using computer simulations matching the events, they determined these pseudo-shocks could carry enough energy and plasma to heat the inner corona.

    2
    Animated computer simulation shows how the pseudo-shock is ejected and becomes disconnected from the plasma below (green). Credits: Abhishek Srivastava IIT (BHU)/Joy Ng, NASA’s Goddard Space Flight Center

    The scientists believe the pseudo-shocks are ejected by magnetic reconnection — an explosive tangling of magnetic field lines, which often occurs in and around sunspots. The pseudo-shocks have only been observed around the rims of sunspots so far, but scientists expect they’ll be found in other highly magnetized regions as well.

    3
    The tadpole-shaped pseudo-shocks, shown in dashed white box, are ejected from highly magnetized regions on the solar surface. Credits: Abhishek Srivastava IIT (BHU)/Joy Ng, NASA’s Goddard Space Flight Center

    Over the past five years, IRIS has kept an eye on the Sun in its 10,000-plus orbits around Earth. It’s one of several in NASA’s Sun-staring fleet that have continually observed the Sun over the past two decades. Together, they are working to resolve the debate over coronal heating and solve other mysteries the Sun keeps.

    “From the beginning, the IRIS science investigation has focused on combining high-resolution observations of the solar atmosphere with numerical simulations that capture essential physical processes,” said Bart De Pontieu research scientist at Lockheed Martin Solar & Astrophysics Laboratory in Palo Alto, California. “This paper is a nice illustration of how such a coordinated approach can lead to new physical insights into what drives the dynamics of the solar atmosphere.”

    The newest member in NASA’s heliophysics fleet, Parker Solar Probe, may be able to provide some additional clues to the coronal heating mystery.

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

    Launched in 2018, the spacecraft flies through the solar corona to trace how energy and heat move through the region and to explore what accelerates the solar wind as well as solar energetic particles. Looking at phenomena far above the region where pseudo-shocks are found, Parker Solar Probe’s investigation hopes to shed light on other heating mechanisms, like nanoflares and electromagnetic waves. This work will complement the research conducted with IRIS.

    “This new heating mechanism could be compared to the investigations that Parker Solar Probe will be doing,” said Aleida Higginson, deputy project scientist for Parker Solar Probe at Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. “Together they could provide a comprehensive picture of coronal heating.”

    Related Links:

    Learn more about NASA’s IRIS Mission
    NASA’s Parker Solar Probe and the Curious Case of the Hot Corona
    Learn more about NASA’s Parker Solar Probe

    See the full article here.


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

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


    NASA/Goddard Campus

     
  • richardmitnick 1:24 pm on February 13, 2019 Permalink | Reply
    Tags: , , , , ExtremeTech, , Solar research   

    From ExtremeTech: “Solar Probe Begins Its Second Orbit of the Sun” 

    From ExtremeTech

    Jan 31, 2019
    Ryan Whitwam

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

    NASA’s Parker solar surveyor became a record-setter at the beginning of its mission when it took the title of fastest spacecraft in history from the wildly successful New Horizons probe. It made history again a few weeks later by flying through the sun’s corona and beaming back data. Now, NASA reports that Parker has completed a full orbit of the sun, and it’s diving back for another pass.

    Parker entered full operational status on Jan. 1 with all systems operating normally. It has started relaying mountains of data via the Deep Space network — NASA says it has collected more than 17 gigabytes so far. Parker has collected so much data that it’ll take several more months to get all of it sent back. The data dump from the first orbit should be done just in time for Parker to dive into the sun’s corona again.

    NASA Deep Space Network

    In preparation for the upcoming solar pass, NASA is busily clearing space on the probe’s internal solid state drives. As data makes it back to Earth, NASA deletes the corresponding files on Parker. The spacecraft is also getting new navigational information, which NASA transmits one month at a time.

    NASA says it expects Parker to reach perihelion (the closest approach to the sun) on Apr. 4. This will be the second of 24 planned orbits that promise to advance our understanding of the sun. Parker’s mission has been in the works for years. NASA has long wanted to study the sun’s corona, but the technology to protect a probe was beyond our abilities until just recently. You’d probably expect the surface of the sun to be hotter than the space around it, but that’s not the case. The corona of ionized plasma surrounding the sun is around one million Kelvin, 300 times hotter than the surface.

    1

    See the full article here .

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  • richardmitnick 1:18 pm on December 13, 2018 Permalink | Reply
    Tags: , Solar research, The Parker Solar Probe takes its first up-close look at the sun   

    From Science News: “The Parker Solar Probe takes its first up-close look at the sun” 

    From Science News

    December 12, 2018
    Lisa Grossman

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

    The spacecraft broke speed and distance records on its initial solar flyby.

    1
    FIRST LOOK One of the first images NASA’s Parker Solar Probe took during its close encounter with the sun shows a streamer of plasma in the outer solar atmosphere, or corona. The probe took this image November 8 at a distance of about 27 million kilometers from the sun’s surface. The bright dot below the streamer is Jupiter. Parker Solar Probe/NASA and Naval Research Laboratory

    NASA’s Parker Solar Probe has met the sun and lived to tell the tale.

    The sun-grazing spacecraft has already broken the records for the fastest space probe and the nearest brush any spacecraft has made with the sun. Now the probe is sending data back from its close solar encounter, scientists reported December 12 at the American Geophysical Union meeting in Washington, D.C.

    “What we are looking at now is completely brand new,” solar physicist Nour Raouafi of Johns Hopkins University Applied Physics Lab in Laurel, Md., said at a news conference. “Nobody looked at this before.”

    Parker launched August 12 (SN Online: 8/12/18) and will make 24 close passes by the sun over the next seven years, eventually going to within about 6 million kilometers of the sun’s surface (SN: 7/21/18, p. 12). The spacecraft made its first close flyby November 6, swooping to within roughly 24 million kilometers of the solar surface. That’s about twice as close to the sun as the previous closest spacecraft, the Helios spacecraft in the 1970s. At peak speed, Parker was racing at about 375,000 kilometers per hour, roughly twice Helios’ speed.

    But because the probe was on the opposite side of the sun from Earth during the flyby, Parker didn’t start relaying its observations until December 7.

    After the probe emerged from behind the sun, the Parker team got its first up-close look at the wispy outer solar atmosphere, called the corona. One of the first images from Parker’s camera shows unprecedented detail in a solar streamer, a filament of plasma in the corona. The team hopes that Parker’s data will help solve the mystery of why the corona is about 300 times as hot as the sun’s surface (SN Online: 8/20/17).

    Only about one-fifth of the data recorded during Parker’s initial flyby will reach scientists before the sun gets between Earth and the spacecraft again. The rest of the data will be downlinked next year, between March and May. Scientists hope to start publishing results soon after.

    “If you ask any scientist in the team or even outside what to expect, I think the answer would be, we don’t really know,” Raouafi said. “We are almost certain we’ll make new discoveries.”

    See the full article here .


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  • richardmitnick 9:41 am on December 4, 2018 Permalink | Reply
    Tags: , , , CLASP-Chromospheric Lyman-Alpha Spectro-Polarimeter, , , , Solar chromosphere, Solar research   

    From Instituto de Astrofísica de Canarias – IAC via Manu Garcia: “A Sun more complex than expected” 


    From Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    IAC

    From Instituto de Astrofísica de Canarias – IAC

    Nov. 28, 2018

    Contacts at the IAC:
    Javier Trujillo Bueno
    jtb@iac.es

    Jiri Stepan
    jiri.stepan@asu.cas.cz

    Andrés Asensio Ramos
    aasensio@iac.es

    Tanausú del Pino Alemán:
    tanausu@iac.es

    1
    FIGURE 1: View of the structure of temperature via a vertical section in a three – dimensional (3D) model of the solar atmosphere resulting from a magneto-hydrodynamic simulation chromosphere (see Carlsson et al 2016. A & A, 585, A4 ). The solid curve shows the heights (Z) in this model from which the photons from the center of the Lyman-α observed by CLASP (note that almost coincides with the transition region between the chromosphere and the crown model) line. The summary in this press release research shows that in the solar atmosphere the geometry of the transition region is much more complex. For more details see Trujillo Good and the CLASP team (2018; The Astrophysical Journal Letters, 866, L15).

    2
    FIGURE 2: Negative high image resolution chromosphere obtained
    with an instrument selected central radiation of a cromosférica line,
    which gives information about the structure of the plasma around 300 km
    below the transition region. Credit: J. Harvey (NSO, USA..).

    The CLASP experiment (Chromospheric Lyman-Alpha Spectro-Polarimeter) was launched on 2015 September 3. The instrument, onboard a NASA suborbital rocket, measured with great success and for the first time the linear polarization of the strongest spectral line of the solar ultraviolet spectrum, the hydrogen Lyman-α line.

    IAC CLASP Chromospheric Lyman-Alpha Spectro-Polarimeter

    This international experiment (Japan, USA and Europe) was motivated by theoretical investigations carried out in 2011 at the Instituto de Astrofísica de Canarias (IAC). Thanks to the unprecedented observations provided by the CLASP instrument, the scientific team was able to confirm most of the theoretical predictions. However, the observed polarization signals, contrary to those calculated in today’s theoretical models of the solar atmosphere, do not show any significant variation in their line-center amplitude when the line of sight goes from the center to the edge of the solar disk. “This was a very interesting surprise that aroused great scientific interest, because the spectral lines of the solar visible spectrum (which can be observed with ground-based telescopes) show such a variation”, says Javier Trujillo Bueno, professor of the Spanish Research Council at the IAC and one of the principal investigators of CLASP.

    The radiation of the Lyman-α line encodes information about the physical properties of the transition region, an enigmatic geometrically thin region where in less than 100 km the temperature suddenly jumps from the ten thousand degrees of the chromosphere to the million degrees of the corona. It is in these regions of the outer solar atmosphere where the explosive phenomena that can affect the Earth’s magnetosphere takes place. “The puzzling lack of a clear variation in the amplitude of the polarization signal when going from the center to the edge of the solar disk hides clues about the structure of the transition region”, says Jiri Stepan of the Astronomical Institute of the Academy of Sciences of the Czech Republic and one of the members of CLASP, presently on a working visit at the IAC.

    The fact that the CLASP observations cannot be reproduced by today’s models of the solar atmosphere suggests that the 3D structure of the chromosphere-corona transition region is much more complex than previously thought. In order to confirm this idea, the scientific team has carried out a complex theoretical investigation in order to determine the magnetization and geometrical complexity of the transition region that best explains the experimental data.

    With the help of the MareNostrum supercomputer of the National Supercomputing Center in Barcelona, the researchers have calculated what would be the expected polarization signals for a large number of 3D atmospheric models, constructed by changing the degree of magnetization and geometrical complexity of the 3D solar model atmosphere illustrated in Figure 1.

    MareNostrum Lenovo supercomputer of the National Supercomputing Center in Barcelona

    Such study has led to two important conclusions, namely, the transition region of the atmospheric model that most likely explains the CLASP observations has a significantly larger degree of geometrical complexity and a smaller degree of magnetization. The results of this investigation make it evident the need to develop more realistic 3D models of the solar atmosphere, by including phenomena such as spicules, ubiquitous in high-resolution observations of the line-core intensity in strong chromospheric lines (see Figure 2), but not present in today’s 3D models of the solar atmosphere.

    The Principal Investigators of the CLASP project are:

    Amy Winebarger (NASA Marshall Space Flight Center, NASA/MSFC)
    Ryouei Kano (National Astronomical Observatory of Japan, NAOJ)
    Frédéric Auchère (Institut d’Astrophysique Spatiale, IAS)
    Javier Trujillo Bueno (Instituto de Astrofísica de Canarias, IAC)

    Related press releases:

    CLASP has a successful mission
    A new research window in Solar Physics: Ultraviolet Spectropolarimetry

    See the full article here.


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    The Instituto de Astrofísica de Canarias(IAC) is an international research centre in Spain which comprises:

    The Instituto de Astrofísica, the headquarters, which is in La Laguna (Tenerife).
    The Centro de Astrofísica en La Palma (CALP)
    The Observatorio del Teide (OT), in Izaña (Tenerife).

    These centres, with all the facilities they bring together, make up the European Northern Observatory(ENO).

    The IAC is constituted administratively as a Public Consortium, created by statute in 1982, with involvement from the Spanish Government, the Government of the Canary Islands, the University of La Laguna and Spain’s Science Research Council (CSIC).

    The International Scientific Committee (CCI) manages participation in the observatories by institutions from other countries. A Time Allocation Committee (CAT) allocates the observing time reserved for Spain at the telescopes in the IAC’s observatories.

    The exceptional quality of the sky over the Canaries for astronomical observations is protected by law. The IAC’s Sky Quality Protection Office (OTPC) regulates the application of the law and its Sky Quality Group continuously monitors the parameters that define observing quality at the IAC Observatories.

    The IAC’s research programme includes astrophysical research and technological development projects.

    The IAC is also involved in researcher training, university teaching and outreachactivities.

    The IAC has devoted much energy to developing technology for the design and construction of a large 10.4 metre diameter telescope, the ( Gran Telescopio CANARIAS, GTC), which is sited at the Observatorio del Roque de los Muchachos.



    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, SpainGran Telescopio CANARIAS, GTC

     
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