Featured Research

from universities, journals, and other organizations

Magnetic 'ropes' tie down solar eruptions

Date:
April 26, 2010
Source:
Royal Astronomical Society (RAS)
Summary:
Over the last century, astronomers have become very aware of how just dynamic the Sun really is. One of the most dramatic manifestations of this is a coronal mass ejection (CME) where billions of tons of matter is thrown into space. If a CME reaches the Earth it creates inclement ‘space weather’ that can disrupt communications, power grids and the delicate systems on orbiting satellites. This potential damage means there is a keen interest in understanding exactly what triggers a CME outburst. Now researchers have used data from the Hinode spacecraft, revealing new details of the formation of an immense magnetic structure that erupted to produce a CME on the 7th December 2007.

The three images reveal gases trapped in the flux rope at different temperatures, from 1.5 million degrees Celsius in the image on the left through to 2.5 million degrees Celsius in the right hand image. These were made with data taken by the EIS telescope, an instrument built by a team led by UCL-MSSL and deployed on the Hinode spacecraft (a joint JAXA/UK/NASA mission).
Credit: JAXA/ISAS/NASA/STFC

Over the last century, astronomers have become very aware of how just dynamic the Sun really is. One of the most dramatic manifestations of this is a coronal mass ejection (CME) where billions of tons of matter is thrown into space. If a CME reaches the Earth it creates inclement 'space weather' that can disrupt communications, power grids and the delicate systems on orbiting satellites. This potential damage means there is a keen interest in understanding exactly what triggers a CME outburst.

Now a team of researchers from University College London (UCL) has used data from the Hinode spacecraft, revealing new details of the formation of an immense magnetic structure that erupted to produce a CME on the 7th December 2007. Lead researcher Dr Lucie Green will present their results April 12 at the RAS National Astronomy Meeting in Glasgow.

The Sun's behaviour is shaped by the presence of magnetic fields that thread through the solar atmosphere. The magnetic fields may take on different shapes from uniform arches to coherent bundles of field lines known as 'flux ropes'. Understanding the exact structure of magnetic fields is a crucial part of the effort to determine how the fields evolve and the role they play in solar eruptions. In particular, flux ropes are thought to play a vital role in the CME process, having been frequently detected in interplanetary space as CMEs reach the vicinity of the Earth.

Dr. Green says, "Magnetic flux ropes have been observed in interplanetary space for many years now and they are widely invoked in theoretical descriptions of how CMEs are produced. We now need observations to confirm or reject the existence of flux ropes in the solar atmosphere before an eruption takes place to see whether our theories are correct."

The formation of the flux rope requires that significant energy is stored in the solar atmosphere. The rope is expected to remain stable whilst the solar magnetic field in the vicinity holds it down.

But at some point the structure becomes unstable and it erupts to produce a CME. Using data from the Hinode spacecraft Dr. Green has shown that a flux rope formed in the solar atmosphere over the 2.5 days that preceded the December 2007 event. Evidence for the flux rope takes the form of S shaped structures which are clearly seen by one of the Hinode instruments, the UK-led Extreme-Ultraviolet Imaging Telescope.

The key point to understanding and predicting the formation of CMEs is to know when the flux rope becomes unstable. Combining the observations of the S shaped structure with information on how the magnetic field in the region evolves has enabled Dr.Green to work out when this happened. The work shows that over 30% of the magnetic field of the region had been transformed into the flux rope before it became unstable, three times what has been suggested in theory.

Dr Green sees a better understanding of magnetic flux ropes and their role in emissions from the Sun and other stars as one of the most pressing questions not just for solar physics but astronomy as a whole.

She comments, "Flux ropes are thought to play a vital role in the evolution of the magnetic field of the Sun. However, the physics of flux ropes is applied across the Universe. For example, a solar physics model of flux rope ejection was recently used to explain the jets driven by the accretion disks around the supermassive black holes found in the centre of galaxies."


Story Source:

The above story is based on materials provided by Royal Astronomical Society (RAS). Note: Materials may be edited for content and length.


Cite This Page:

Royal Astronomical Society (RAS). "Magnetic 'ropes' tie down solar eruptions." ScienceDaily. ScienceDaily, 26 April 2010. <www.sciencedaily.com/releases/2010/04/100412084549.htm>.
Royal Astronomical Society (RAS). (2010, April 26). Magnetic 'ropes' tie down solar eruptions. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/2010/04/100412084549.htm
Royal Astronomical Society (RAS). "Magnetic 'ropes' tie down solar eruptions." ScienceDaily. www.sciencedaily.com/releases/2010/04/100412084549.htm (accessed September 19, 2014).

Share This



More Earth & Climate News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Wildfires in CA Burn Forest Asunder

Raw: Wildfires in CA Burn Forest Asunder

AP (Sep. 18, 2014) An out-of-control Northern California wildfire has nearly 2,800 people from their homes as it continues to grow, authorities said Thursday. Authorities said a man has been arrested on suspicion of arson for starting the fire on Saturday. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins