Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Seeing double: NASA missions measure solar flare from 2 spots in space

20.04.2016

Solar flares are intense bursts of light from the sun. They are created when complicated magnetic fields suddenly and explosively rearrange themselves, converting magnetic energy into light through a process called magnetic reconnection - at least, that's the theory, because the signatures of this process are hard to detect. But during a December 2013 solar flare, three solar observatories captured the most comprehensive observations of an electromagnetic phenomenon called a current sheet, strengthening the evidence that this understanding of solar flares is correct.

These eruptions on the sun eject radiation in all directions. The strongest solar flares can impact the ionized part of Earth's atmosphere - the ionosphere - and interfere with our communications systems, like radio and GPS, and also disrupt onboard satellite electronics. Additionally, high-energy particles - including electrons, protons and heavier ions - are accelerated by solar flares.


During a December 2013 solar flare, three NASA missions observed a current sheet form -- a strong clue for explaining what initiates the flares. This animation shows four views of the flare from NASA's Solar Dynamics Observatory, NASA's Solar and Terrestrial Relations Observatory, and JAXA/NASA's Hinode, allowing scientists to make unprecedented measurements of its characteristics. The current sheet is a long, thin structure, especially visible in the views on the left. Those two animations depict light emitted by material with higher temperatures, so they better show the extremely hot current sheet.

Credits: NASA/JAXA/SDO/STEREO/Hinode (courtesy Zhu, et al.)

Unlike other space weather events, solar flares travel at the speed of light, meaning we get no warning that they're coming. So scientists want to pin down the processes that create solar flares - and even some day predict them before our communications can be interrupted.

"The existence of a current sheet is crucial in all our models of solar flares," said James McAteer, an astrophysicist at New Mexico State University in Las Cruces and an author of a study on the December 2013 event, published on April 19, 2016, in the Astrophysical Journal Letters. "So these observations make us much more comfortable that our models are good."

And better models lead to better forecasting, said Michael Kirk, a space scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who was not involved in the study. "These complementary observations allowed unprecedented measurements of magnetic reconnection in three dimensions," Kirk said. "This will help refine how we model and predict the evolution of solar flares."

Looking at Current Sheets

A current sheet is a very fast, very flat flow of electrically-charged material, defined in part by its extreme thinness compared to its length and width. Current sheets form when two oppositely-aligned magnetic fields come in close contact, creating very high magnetic pressure.

Electric current flowing through this high-pressure area is squeezed, compressing it down to a very fast and thin sheet. It's a bit like putting your thumb over the opening of a water hose - the water, or, in this case, the electrical current, is forced out of a tiny opening much, much faster. This configuration of magnetic fields is unstable, meaning that the same conditions that create current sheets are also ripe for magnetic reconnection.

"Magnetic reconnection happens at the interface of oppositely-aligned magnetic fields," said Chunming Zhu, a space scientist at New Mexico State University and lead author on the study. "The magnetic fields break and reconnect, leading to a transformation of the magnetic energy into heat and light, producing a solar flare."

Because current sheets are so closely associated with magnetic reconnection, observing a current sheet in such detail backs up the idea that magnetic reconnection is the force behind solar flares.

"You have to be watching at the right time, at the right angle, with the right instruments to see a current sheet," said McAteer. "It's hard to get all those ducks in a row."

This isn't the first time scientists have observed a current sheet during a solar flare, but this study is unique in that several measurements of the current sheet - such as speed, temperature, density and size - were observed from more than one angle or derived from more than method.

This multi-faceted view of the December 2013 flare was made possible by the wealth of instruments aboard three solar-watching missions: NASA's Solar Dynamics Observatory, or SDO, NASA's Solar and Terrestrial Relations Observatory, or STEREO - which has a unique viewing angle on the far side of the sun - and Hinode, which is a collaboration between the space agencies of Japan, the United States, the United Kingdom and Europe led by the Japan Aerospace Exploration Agency.

Even when scientists think they've spotted something that might be a current sheet in solar data, they can't be certain without ticking off a long list of attributes. Since this current sheet was so well-observed, the team was able to confirm that its temperature, density, and size over the course of the event were consistent with a current sheet.

As scientists work up a better picture of how current sheets and magnetic reconnection lead to solar eruptions, they'll be able to produce better models of the complex physics happening there - providing us with ever more insight on how our closest star affects space all around us.

###

This research was funded by a CAREER grant from the National Science Foundation awarded to James McAteer.

Karen Fox | EurekAlert!

More articles from Physics and Astronomy:

nachricht A tale of two pulsars' tails: Plumes offer geometry lessons to astronomers
18.01.2017 | Penn State

nachricht Studying fundamental particles in materials
17.01.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie

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: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>