Tracking the constantly moving material requires state-of-the-art telescopes with the highest resolution possible. By combining images from NASA's Solar Dynamics Observatory (SDO) and a new generation telescope called the New Solar Telescope (NST) at Big Bear Solar Observatory in Big Bear City, Calif. scientists have for the first time observed a new facet of the system: especially narrow loops of solar material scattered on the sun's surface, which are connected to higher lying, wider loops. These ultrafine loops, and their wider cousins may also help with the quest to determine how temperatures rise throughout the corona.
Left: An image of a magnetic loop complex as captured on July 22, 2011 by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory. The image shows light in the 193 Angstrom wavelength. Credit: NASA/SDO/AIA
Right: This covers the area of the sun roughly in the middle of that shown in the SDO image on the left, as captured by the New Space Telescope. Together the images were used to observe and analyze ultrafine loops of magnetized material in the sun's atmosphere. Credit: NST
"We're used to seeing magnetic loops on the sun," says Philip Goode of the New Jersey Institute of Technology in Newark, NJ, who was a co-author on a paper on these results in the Astrophysical Journal on May 1, 2012. "But we've never seen ones lying so low, that were so cold, or that were so narrow. These loops are 10 times narrower and at least 10 times cooler than the higher loops often seen by SDO."
Goode and his colleagues, Wenda Cao and Haisheng Ji used the two telescopes to observe these loops in data from July 22, 2011. The combination of NST and SDO allowed the researchers to trace the flow of energy from the cooler ultrafine loops observed with NST to cospatial and cotemporal brightenings seen by SDO in the overlying million degree corona. In the NST observations, the loops show a nearly consistent width of what Goode says is a "surprisingly narrow diameter" of only about 60 miles across. The team aligned images from the NST, which can measure magnetic fields to high resolution, with the SDO images to find the magnetic footprint of these loops on the sun. The magnetic maps showed that the loops lined up with fine lanes on the sun that separate what's known as granules – cells on the star's surface that can be loosely understood as bubbles of boiling solar material that rise up from below. After the material, or plasma, rises up into the granules, it sweeps out to the sides, and flows back down these intergranular lanes. The lanes are consequently believed to contain concentrated magnetic fields, the perfect place for the origin of these newly spotted magnetic loops. The very position and shape of the ultrafine loops, therefore, help confirm models of the sun's surface.
Goode and his colleagues did more than just categorize the size and shape of the loops, however. They also tracked the loops through time as they rose up into the sun's corona, a process that may help solve a persistent question in solar physics, namely why the sun's atmosphere, or corona is so hot.
Scientists in the early 1940s discovered that the sun's atmosphere is some thousand times hotter than its surface. Determining just what processes heat those gases up to millions of degrees has been a key research area ever since.
"There have been many suggestions over the years as to what mechanism can make the atmosphere a thousand times hotter than the surface of the sun," says Goode. "They basically come in two categories. The first is that there's some kind of continuous magnetic energy adding heat. The second is that there's an impulsive, intermittent movement that adds heat. And there are, of course, all kinds of variations and mixtures of each theme."
In this case, the appearance of the ultrafine loops seems to be correlated to intense magnetic field collisions. The largest groups of loops also corresponded to solar phenomena called Type II spicules, which some theories postulate contribute to coronal heating.
"We observe an impulsive event at the sun's surface, and this excites low-lying and higher-lying, wider loops almost simultaneously," says Goode. "It's just a correlation at this point, but for the first time we've observed something happen at the surface and we can track it up through heating of the corona. This doesn't answer the question of whether it's the only mechanism that heats the corona, but it certainly seems to be at least one mechanism."
In addition to the value of having seen such fine structures for the first time, Goode and his colleagues believe this is a great example of how the NST can coordinate with other instruments, such as an upcoming NASA Explorer called the Interface Region Imaging Spectrograph or IRIS, due to launch no earlier than December 2012. IRIS will focus exclusively on the area of the sun's atmosphere at the base of the corona, an area crucial for coronal heating. The NST's capabilities will mesh nicely with this since it can measure magnetic fields in the same regions IRIS will be observing.For more information about the IRIS mission, visit:
Susan Hendrix | EurekAlert!
UNH scientists help provide first-ever views of elusive energy explosion
16.11.2018 | University of New Hampshire
NASA keeps watch over space explosions
16.11.2018 | NASA/Goddard Space Flight Center
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences