Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Five Spacecraft Join to Solve an Auroral Puzzle

20.05.2003

Five spacecraft have made a remarkable set of observations, leading to a breakthrough in understanding the origin of a peculiar and puzzling type of aurora. Seen as bright spots in Earth’s atmosphere and called "dayside proton auroral spots," they are now known to occur when fractures appear in the Earth’s magnetic field, allowing particles emitted from the Sun to pass through and collide with molecules in our atmosphere.

On March 18, 2002, a jet of energetic solar protons collided with the Earth’s atmosphere and created a bright "spot" seen by NASA’s IMAGE spacecraft, just as the European Space Agency’s (ESA) four Cluster spacecraft passed overhead and straight through the proton jet. This is the first time that a precise and direct connection between the proton jet and bright spot has been made, and it results from the simultaneous observations by Cluster and IMAGE. The results of the study are published May 21 in Geophysical Research Letters, a journal of the American Geophysical Union, in a paper by Tai Phan of the University of California in Berkeley and 24 international colleagues.

Earth’s magnetic field acts as a shield, protecting the planet from the constant stream of tiny particles ejected by the Sun, known as the solar wind. The solar wind itself is a stream of hydrogen atoms, separated into their constituent protons and electrons. When electrons find routes into our atmosphere, they collide with and "excite" the atoms in the air. When these excited atoms release their energy, it is emitted as light, creating the glowing "curtains" we see as the aurora borealis in the far north and aurora australis in the far south. Dayside proton auroral spots are caused by protons "stealing" electrons from the atoms in our atmosphere.

An extensive analysis of the Cluster results has now shown that the region was experiencing a turbulent event known as "magnetic reconnection." Such a phenomenon takes place when the Earth’s usually impenetrable magnetic field fractures and has to find a new stable configuration. Until the field mends itself, solar protons leak through the gap and jet into Earth’s atmosphere, creating the dayside proton aurora.

Philippe Escoubet, ESA’s Cluster Project Scientist, comments, "Thanks to Cluster’s observations, scientists can directly and firmly link for the first time a dayside proton auroral spot and a magnetic reconnection event."

Tai Phan, leader of the investigation, now looks forward to a new way of studying the Earth’s protective shield. He says, "This result has opened up a new area of research. We can now watch dayside proton aurorae and use those observations to know where and how the cracks in the magnetic field are formed and how long the cracks remain open. That makes it a powerful tool to study the entry of the solar wind into the Earth’s magnetosphere."

Proton auroras were globally imaged for the first time by NASA’s IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) spacecraft, which revealed the presence of dayside proton auroral spots. ESA’s Cluster is a collection of four spacecraft, launched on two Russian rockets during the summer of 2000. They fly in formation around the Earth, relaying the most detailed information ever about how the solar wind affects the planet.

The principal investigators for the instruments in the current study were Henri Reme of CESR/Toulouse, France (Cluster Proton Detectors), Andre Balogh of Imperial College, London, United Kingdom (Cluster Magnetic Field Instrument), and Stephen Mende of University of California, Berkeley (IMAGE/FUV).

The current study was funded by NASA and other organizations.

Harvey Leifert | AGU
Further information:
http://www.agu.org

More articles from Physics and Astronomy:

nachricht NASA's Fermi catches gamma-ray flashes from tropical storms
25.04.2017 | NASA/Goddard Space Flight Center

nachricht DGIST develops 20 times faster biosensor
24.04.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017 | Physics and Astronomy

Researchers invent process to make sustainable rubber, plastics

25.04.2017 | Materials Sciences

Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017

25.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>