Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cluster hits the magnetic bull’s-eye

19.07.2006
ESA's spacecraft constellation Cluster has hit the magnetic bull's-eye. The four spacecraft surrounded a region within which the Earth’s magnetic field was spontaneously reconfiguring itself.
This is the first time such an observation has been made and gives astronomers a unique insight into the physical process responsible for the most powerful explosions that can occur in the Solar System: the magnetic reconnection.

When looking at the static pattern of iron filings around a bar magnet, it is difficult to imagine how changeable and violent magnetic fields can be in other situations.

In space, different regions of magnetism behave somewhat like large magnetic bubbles, each containing electrified gas known as plasma. When the bubbles meet and are pushed together, their magnetic fields can break and reconnect, forming a more stable magnetic configuration. This reconnection of magnetic fields generates jets of particles and heats the plasma.

At the very heart of a reconnection event, there must be a three dimensional zone where the magnetic fields break and reconnect. Scientists call this region the null point but, until now, have never been able to positively identify one, as it requires at least four simultaneous points of measurements.

On 15 September 2001, the four Cluster spacecraft were passing behind the Earth. They were flying in a tetrahedral formation with separations between the spacecraft of over 1 000 kilometres. As they flew through the Earth’s magnetotail, which stretches out behind the night-time side of our planet, they surrounded one of the suspected null points.

The data returned by the spacecraft have been extensively analysed by an international team of scientists led by Dr. C. Xiao from Chinese Academy of Sciences, Prof. Pu from Peking University, Prof. Wang from Dalian University of Technogy. Xiao and his colleagues used the Cluster data to deduce the three-dimensional structure and size of the null point, revealing a surprise.

The null point exists in an unexpected vortex structure about 500 kilometres across. "This characteristic size has never been reported before in observations, theory or simulations," say Xiao, Pu and Wang.

This result is a major achievement for the Cluster mission as it gives scientists their first look at the very heart of the reconnection process.

Throughout the Universe, magnetic reconnection is thought to be a fundamental process that drives many powerful phenomena, such as the jets of radiation seen escaping from distant black holes, and the powerful solar flares in our own Solar system that can release more energy than a billion atomic bombs.

On a smaller scale, reconnection at the dayside boundary of the Earth’s magnetic field allows solar gas through, triggering a specific type of aurora called 'proton aurora'.

Understanding what sparks magnetic reconnection will also help scientists trying to harness nuclear fusion for energy production. In tokamak fusion reactors, spontaneous magnetic reconfigurations rob the process of its controllability. By understanding how magnetic fields reconnect, fusion scientists hope to be able to design better reactors that prevent this from taking place.

Having identified one null point, the team now hopes to score future bull’s-eyes to compare nulls and see whether their first detection possessed a configuration that is rare or common.

Philippe Escoubet | alfa
Further information:
http://www.esa.int/esaSC/SEMAYXAUQPE_index_0.html

More articles from Physics and Astronomy:

nachricht Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of Technology

nachricht Physicists discover mechanism behind granular capillary effect
24.05.2017 | University of Cologne

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: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>