Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hotspots in Fountains on the Sun's Surface May Help Explain Coronal Heating Mystery

07.01.2011
Observations from NASA's Solar Dynamics Observatory (SDO) and the Japanese satellite Hinode show that some gas in the giant, fountain-like jets in the sun's atmosphere known as spicules can reach temperatures of millions of degrees. The finding offers a possible new framework for how the sun's high atmosphere gets so much hotter than the surface of the sun.

What makes the high atmosphere, or corona, so hot – over a million degrees, compared to the sun surface's 10,000 degrees Fahrenheit -- remains a poorly understood aspect of the sun's complicated space weather system. That weather system can reach Earth, causing auroral lights and, if strong enough, disrupting Earth's communications and power systems. Understanding such phenomena, therefore, is an important step towards better protecting our satellites and power grids.

"The traditional view is that all the heating happens higher up in the corona," says Dean Pesnell, who is SDO's project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "The suggestion in this paper is that cool gas is being ejected from the sun's surface in spicules and getting heated on its way to the corona."

Spicules were first named in the 1940s, but were hard to study in detail until recently, says Bart De Pontieu of Lockheed Martin's Solar and Astrophysics Laboratory, Palo Alto, Calif. who is the lead author on a paper on this subject in the January 7, 2011 issue of Science magazine.

In visible light, spicules can be seen to send large masses of so-called plasma – the electromagnetic gas that surrounds the sun – up through the lower solar atmosphere or photosphere. The amount of material sent up is stunning, some 100 times as much as streams away from the sun in the solar wind towards the edges of the solar system. But nobody knew if they contained hot gas.

"Heating of spicules to the necessary hot temperatures has never been observed, so their role in coronal heating had been dismissed as unlikely," says De Pontieu.

Now, De Pontieu's team -- which included researchers at Lockheed Martin, the High Altitude Observatory of the National Center for Atmospheric Research (NCAR) in Colorado and the University of Oslo, Norway -- was able to combine images from SDO and Hinode to produce a more complete picture of the gas inside these gigantic fountains.

The scientists found that a large fraction of the gas is heated to a hundred thousand degrees, while a small fraction is heated to millions of degrees. Time-lapsed images show that this material spews up into the corona, with most falling back down towards the surface of the sun. However, the small fraction of the gas that is heated to millions of degrees does not immediately return to the surface. Given the large number of spicules on the Sun, and the amount of material in the spicules, the scientists believe that if even some of that super hot plasma stays aloft it would make a contribution to coronal heating.

Astrophysicist Jonathan Cirtain, who is the U.S. project scientist for Hinode at NASA's Marshall Space Flight Center, Huntsville, Ala., says that incorporating such new information helps address an important question that reaches far beyond the sun. "This breakthrough in our understanding of the mechanisms which transfer energy from the solar photosphere to the corona addresses one of the most compelling questions in stellar astrophysics: How is the atmosphere of a star heated?" he says. "This is a fantastic discovery, and demonstrates the muscle of the NASA Heliophysics System Observatory, comprised of numerous instruments on multiple observatories."

Hinode is the second mission in NASA's Solar Terrestrial Probes program, the goal of which is to improve understanding of fundamental solar and space physics processes. The mission is led by the Japan Aerospace Exploration Agency (JAXA) and the National Astronomical Observatory of Japan (NAOJ). The collaborative mission includes the U.S., the United Kingdom, Norway and Europe. NASA Marshall manages Hinode U.S. science operations and oversaw development of the scientific instrumentation provided for the mission by NASA, academia and industry. The Lockheed Martin Advanced Technology Center is the lead U.S. investigator for the Solar Optical Telescope on Hinode.

SDO is the first mission in a NASA science program called Living With a Star, the goal of which is to develop the scientific understanding necessary to address those aspects of the sun-Earth system that directly affect our lives and society. NASA Goddard built, operates, and manages the SDO spacecraft for NASA's Science Mission Directorate in Washington.

Susan Hendrix | EurekAlert!
Further information:
http://www.nasa.gov
http://www.nasa.gov/centers/goddard/news/releases/2011/11-001.html

More articles from Physics and Astronomy:

nachricht Structured light and nanomaterials open new ways to tailor light at the nanoscale
23.04.2018 | Academy of Finland

nachricht On the shape of the 'petal' for the dissipation curve
23.04.2018 | Lobachevsky University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Structured light and nanomaterials open new ways to tailor light at the nanoscale

23.04.2018 | Physics and Astronomy

On the shape of the 'petal' for the dissipation curve

23.04.2018 | Physics and Astronomy

Clean and Efficient – Fraunhofer ISE Presents Hydrogen Technologies at the HANNOVER MESSE 2018

23.04.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>