After more than 60 years, NASA scientists have developed a theory that explains how explosions occur on the Sun and helps better predict geomagnetic storms and solar flares that can impact Earth.
A solar flare can release enough energy to power the entire world for 20,000 years.
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Solar flares are caused by an explosive process called magnetic reconnection, scientists say. Scientists have spent the past half century trying to figure out how this process occurs.
NASA’s Multiscale Magnetospheric Mission (MMS) team has a new theory that explains how the most explosive type of magnetic reconnection – called rapid reconnection – occurs and why it happens at a constant speed.
Magnetic reconnection is a process that occurs in plasma – a fluid-like energetic material that is extremely sensitive to magnetic fields.
From flares on the Sun to near-Earth space to black holes, plasmas throughout the universe undergo magnetic reconnection, which rapidly converts magnetic energy into heat and acceleration.
Although there are several types of magnetic reconnection, one particularly confusing variation is known as rapid reconnection, which occurs at a predictable rate.
“We’ve known for some time that rapid reconnection happens at a certain rate that seems to be pretty constant,” said Barbara Giles, MMS project scientist and research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “But what really drives this rate has been a mystery until now.”
The new research, published in an article in the journal Nature’s Communications Physics, explained how quickly reconnection occurs specifically in collisionless plasmas – a type of plasma whose particles are spread out enough that individual particles do not enter. colliding with each other.
Where reconnection occurs in space, most plasmas are in this collisionless state, including plasma from solar flares and space around Earth.
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The team showed the theory using a common magnetic effect called the Hall effect – a common magnetic phenomenon used in everyday technology, such as vehicle wheel speed sensors and 3D printers, where the sensors measure speed, proximity, positioning or electrical currents.
During rapid magnetic reconnection, charged particles in a plasma – namely ions and electrons – stop moving as a group. When ions and electrons begin to move apart, they give rise to the Hall effect, creating an unstable energy vacuum where reconnection occurs.
The pressure of the magnetic fields around the energy vacuum causes the vacuum to implode, which rapidly releases immense amounts of energy at a predictable rate.
“Ultimately, if we can understand how magnetic reconnection works, then we can better predict events that can affect us on Earth, like geomagnetic storms and solar flares,” Giles said.
“And if we can understand how reconnection is initiated, it will also help energy research because researchers could better control magnetic fields in fusion devices.”
(With contributions from the agency)