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
Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)
Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences