Featured Research

from universities, journals, and other organizations

New Discovery On Magnetic Reconnection To Impact Future Space Missions

Date:
January 31, 2008
Source:
European Space Agency
Summary:
ESA's Cluster mission has, for the first time, observed the extent of the region that triggers magnetic reconnection, and it is much larger than previously thought. This gives future space missions a much better chance of studying it. Space is filled with plasma (a gas composed of ions and electrons, globally neutral) and is threaded by magnetic fields. These magnetic fields store energy which can be released explosively, in a process called magnetic reconnection.

In a plasma (a gas of charged particles), during magnetic reconnection, magnetic field lines of opposite direction break and then reconnect, forming an X-line magnetic topology. The newly reconnected field lines accelerate the plasma away from the X-line.
Credit: Center for Visual computing, Univ. of California Riverside

ESA’s Cluster mission has, for the first time, observed the extent of the region that triggers magnetic reconnection, and it is much larger than previously thought. This gives future space missions a much better chance of studying it.

Space is filled with plasma (a gas composed of ions and electrons, globally neutral) and is threaded by magnetic fields. These magnetic fields store energy which can be released explosively, in a process called magnetic reconnection.

This process plays a key role in numerous astrophysical phenomena: star formation, solar flares and intense aurorae, to name a few. On Earth, magnetic reconnection prevents the efficient production of electricity in controlled fusion reactors, potential sources of electricity for the future.

Schematic of magnetic field lines during reconnection

At the heart of magnetic reconnection is the ‘electron diffusion region’, where reconnection is thought to be triggered. Here, a kink in newly-reconnected magnetic field lines produces large-scale high-velocity jets of plasma.

“Understanding the structure of the diffusion region and its role in controlling the rate at which magnetic energy is converted into particle energy remains a key scientific challenge,” says Dr Michael Shay, University of Delaware, USA.

Until recently, theoretical scientists believed that the electron diffusion region was relatively tiny (width about 2 km, length about 10 km). In the vastness of space, the chance of a spacecraft encountering this region would therefore be exceedingly small.

With increased computational power, simulations showed electron diffusion regions that were a lot more elongated than those seen earlier. It was not possible to judge whether the new finding was real because the length of the region increased with more powerful simulations. Nor it was known whether such a layer would be stable in the real, 3D world.

Comparison between observations and simulation

On 14 January 2003, the four Cluster satellites were crossing the magnetosheath, a turbulent plasma region located just outside Earth’s magnetosphere, when they encountered an electron diffusion region. The length of the observed region measured 3000 km, 300 times longer than the earlier theoretical expectations and four times longer than seen in recent simulations. Nevertheless, the observations strongly support new simulations.

“These Cluster observations are very significant since they are the first measurements of the length of the electron diffusion region in the space environment. The finding drastically changes the way we understand the physics of reconnection,” noted Dr James Drake, University of Maryland, USA.

“This discovery of a large electron diffusion region gives future ESA and NASA missions a much better chance to study it,” said Tai Phan at the University of California at Berkeley, USA, lead author of the paper on the findings.

Magnetic reconnection simulation

Cluster was able to detect the region based on its high-resolution magnetic field, electric field and ion measurements. But to understand the fundamental physics of the electron diffusion region responsible for reconnection, higher time resolution measurements are needed to resolve the layer.

The four spacecraft of NASA’s Magnetospheric Multi-Scale mission, planned for launch in 2014, are being designed for such measurements. Cross-scale, a mission under study at ESA in collaboration with other space agencies, would use 12 spacecraft to probe the diffusion region, whilst simultaneously measuring the consequences of energy released by reconnection in the surrounding environment.

“With the higher probability of encountering the electron diffusion region, we can be confident that future missions will be able to fully understand magnetic reconnection,” said Dr Philippe Escoubet, ESA’s Cluster and Double Star Project Scientist and Cross-scale Study Scientist.

The findings appear in, ‘Evidence for an elongated (> 60 ion skin depths) electron diffusion region during fast magnetic reconnection,’ by T. Phan, J. Drake, M. Shay, F. Mozer and J. Eastwood, published in the Physical Review Letters, on 21 December 2007.


Story Source:

The above story is based on materials provided by European Space Agency. Note: Materials may be edited for content and length.


Cite This Page:

European Space Agency. "New Discovery On Magnetic Reconnection To Impact Future Space Missions." ScienceDaily. ScienceDaily, 31 January 2008. <www.sciencedaily.com/releases/2008/01/080125230056.htm>.
European Space Agency. (2008, January 31). New Discovery On Magnetic Reconnection To Impact Future Space Missions. ScienceDaily. Retrieved August 28, 2014 from www.sciencedaily.com/releases/2008/01/080125230056.htm
European Space Agency. "New Discovery On Magnetic Reconnection To Impact Future Space Missions." ScienceDaily. www.sciencedaily.com/releases/2008/01/080125230056.htm (accessed August 28, 2014).

Share This




More Space & Time News

Thursday, August 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Experiment Tests Whether Universe Is Actually A Hologram

Experiment Tests Whether Universe Is Actually A Hologram

Newsy (Aug. 27, 2014) Researchers at Fermilab are using a device called "The Holometer" to test whether our universe is actually a 2-D hologram that just seems 3-D. Video provided by Newsy
Powered by NewsLook.com
SpaceX’s Falcon 9 Rocket Explodes After Liftoff

SpaceX’s Falcon 9 Rocket Explodes After Liftoff

Newsy (Aug. 23, 2014) The private spaceflight company says it is preparing a thorough investigation into Friday's mishap. Video provided by Newsy
Powered by NewsLook.com
Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Newsy (Aug. 21, 2014) Russian cosmonauts say they've found evidence of sea plankton on the International Space Station's windows. NASA is a little more skeptical. Video provided by Newsy
Powered by NewsLook.com
Space to Ground: Hello Georges

Space to Ground: Hello Georges

NASA (Aug. 18, 2014) Europe's ATV-5 delivers new science and the crew tests smart SPHERES. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
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