A New View of Coronal Waves

December 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: The Sun's X-file under the Spotlight

Related Stories

The Sun's X-file under the Spotlight

September 3, 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 ...

SECCHI team obtains images of the solar wind at Earth

December 7, 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

Blue skies, frozen water detected on Pluto

October 8, 2015

Pluto has blue skies and patches of frozen water, according to the latest data out Thursday from NASA's unmanned New Horizons probe, which made a historic flyby of the dwarf planet in July.

Orbiter views Mars surface fractures

October 8, 2015

The High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter often takes images of Martian sand dunes to study the mobile soils. These images provide information about erosion and ...

How to prepare for Mars? NASA consults Navy sub force

October 5, 2015

As NASA contemplates a manned voyage to Mars and the effects missions deeper into space could have on astronauts, it's tapping research from another outfit with experience sending people to the deep: the U.S. Navy submarine ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

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.