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 Earths atmosphere and called "dayside proton auroral spots," they are now known to occur when fractures appear in the Earths 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 Earths atmosphere and created a bright "spot" seen by NASAs IMAGE spacecraft, just as the European Space Agencys (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.
Earths 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 Earths 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 Earths atmosphere, creating the dayside proton aurora.
Philippe Escoubet, ESA’s Cluster Project Scientist, comments, "Thanks to Clusters 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 Earths 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 Earths magnetosphere."
Proton auroras were globally imaged for the first time by NASAs IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) spacecraft, which revealed the presence of dayside proton auroral spots. ESAs 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
Innovative LED High Power Light Source for UV
22.06.2017 | Omicron - Laserage Laserprodukte GmbH
Spin liquids − back to the roots
22.06.2017 | Universität Augsburg
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.
New Manufacturing Technologies for New Products
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
22.06.2017 | Life Sciences
22.06.2017 | Materials Sciences
22.06.2017 | Materials Sciences