A New View of Coronal Waves

Dec 11, 2009
Images of a solar eruption, each seen before and after the event, in three ways: optical light, X-ray emission, and in the magnetic field strength. Credit: NASA, YNAO, HINODE, and SOHO

(PhysOrg.com) -- The corona is the hot outer region of the sun's atmosphere. The corona is threaded by magnetic fields that loop and twist upwards from the sun's surface, driven by motions of its dense atmosphere.

When one of these magnetic loops snaps open, it can produce a mass ejection and a flare whose X-rays and ejected particles can disrupt communications on earth. It has been known for about fifteen years that there are roughly circular waves rippling through the corona on a scale that spans the entire solar disk. The possible relationship between these waves and solar eruptions or other active phenomena is an active area of research because of the interest in being able to predict solar storm activity.

Coronal waves are suspected of having significant depth into the , but observations from a single orbiting telescope only obtain a two-dimensional picture of wave activity. In 2006, NASA launched the STEREO mission: two identical satellites but in different orbits, to study the three-dimensional structure of solar eruptions.

CfA astronomers Suli Ma, Meredith Wills-Davey, Ting Lin, Gemma Attrill, and Leon Golub used STEREO, together with other sun-observing spacecraft, to investigate the 3-D behavior of coronal waves. In a paper appearing in this week's , they present their analysis of a wave that appeared two years ago, on December 7, 2007, and that produced an eruption and ejection a few minutes later.

The ultraviolet images of the coronal wave obtained from each STEREO satellite are quite different at the start of the observations, but look more and more alike with time. By considering projection effects and the physics of coronal ejections, the scientists conclude that the three-dimensional structure of the waves can significantly influence their observed physical properties.

Provided by Harvard-Smithsonian Center for Astrophysics (news : web)

Explore further: Image: Multicoloured view of supernova remnant

add to favorites email to friend print save as pdf

Related Stories

NASA releases first 3-D images of the sun from STEREO

Apr 23, 2007

NASA's twin Solar Terrestrial Relations Observatory (STEREO) spacecraft have made the first three-dimensional images of the sun. The new view will greatly aid scientists' ability to understand solar physics ...

The Sun's X-file under the Spotlight

Sep 03, 2004

One of the Sun's greatest mysteries is about to be unravelled by UK solar astrophysicists hosting a major international workshop at the University of St Andrews from September 6-9th 2004. For years scientists have been baffled ...

Hinode's X-Ray Telescope Reveals the Sun's Secrets

Mar 21, 2007

Even though the sun is the closest star to Earth and has been studied for hundreds of years, it still holds surprises. The recently launched Hinode spacecraft is one of the latest observatories to probe the ...

The Spooky Sun

Oct 31, 2006

Just in time for Halloween, astronomers have taken a haunting new portrait of the sun. In this color-coded image from the Hinode spacecraft (formerly Solar-B), the sun glows eerily orange as though celebrating ...

Scientists find elusive waves in sun's corona

Aug 30, 2007

Scientists for the first time have observed elusive oscillations in the Sun's corona, known as Alfvén waves, that transport energy outward from the surface of the Sun. The discovery is expected to give researchers ...

SECCHI team obtains images of the solar wind at Earth

Dec 07, 2007

Using the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) instruments on board NASA’s Solar Terrestrial Relations Observatory (STEREO) spacecraft, a consortium of scientists has seen, for the first ...

Recommended for you

Image: Multicoloured view of supernova remnant

9 hours ago

Most celestial events unfold over thousands of years or more, making it impossible to follow their evolution on human timescales. Supernovas are notable exceptions, the powerful stellar explosions that make ...

Ultra-luminous X-ray sources in starburst galaxies

9 hours ago

Ultra-luminous X-ray sources (ULXs) are point sources in the sky that are so bright in X-rays that each emits more radiation than a million suns emit at all wavelengths. ULXs are rare. Most galaxies (including ...

When a bright light fades

10 hours ago

Astronomer Charles Telesco is primarily interested in the creation of planets and stars. So, when the University of Florida's giant telescope was pointed at a star undergoing a magnificent and explosive death, ...

Image: Horsehead nebula viewed in infrared

10 hours ago

Sometimes a horse of a different color hardly seems to be a horse at all, as, for example, in this newly released image from NASA's Spitzer Space Telescope. The famous Horsehead nebula makes a ghostly appearance ...

The Milky Way's new neighbour

10 hours ago

The Milky Way, the galaxy we live in, is part of a cluster of more than 50 galaxies that make up the 'Local Group', a collection that includes the famous Andromeda galaxy and many other far smaller objects. ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

omatumr
1 / 5 (1) Dec 11, 2009
Congratulations on an important study.

Although the Coronal waves may only start at significant depths in the atmosphere, the magnetic fields themselves likely arise from far greater depths - near the solar core.

With kind regards,
Oliver K. Manuel

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.