Washington: Two NASA spacecrafts have provided the most comprehensive movie ever of a mysterious process at the heart of all explosions on the sun - magnetic reconnection.
Magnetic reconnection happens when magnetic field lines come together, break apart and then exchange partners, snapping into new positions and releasing a jolt of magnetic energy.
This process lies at the heart of giant explosions on the sun, such as solar flares and coronal mass ejections, which can fling radiation and particles across the solar system.
Scientists want to better understand this process so they can provide advance warning of such space weather, which can affect satellites near Earth and interfere with radio communications.
One reason why it`s so hard to study is that magnetic reconnection can`t be witnessed directly, because magnetic fields are invisible.
Instead, scientists use a combination of computer modeling and a scant sampling of observations around magnetic reconnection events to attempt to understand what`s going on.
"The community is still trying to understand how magnetic reconnection causes flares," Yang Su, a solar scientist at the University of Graz in Austria, said.
"We have so many pieces of evidence, but the picture is not yet complete," Su said
Now Su has added a new piece of visual evidence.
When searching through observations from NASA`s SDO, short for Solar Dynamics Observatory, Su saw something particularly hard to pull from the data: direct images of magnetic reconnection as it was happening on the sun.
While a few tantalizing images of reconnection have been seen before, this paper shows the first comprehensive set of data that can be used to constrain and improve models of this fundamental process on the sun.
In the SDO movies, light illuminates the arcade of loops as the reconnection process cascades along the length of them. Bright loops lean into the reconnection region from each side.
As the magnetic field lines reconfigure, new loops are ejected downward, while a rope of plasma separates and surges upward. In certain cases, the rope achieves escape velocity and becomes a coronal mass ejection, sending billions of tons of matter out into space.
The research is published in the journal Nature Physics.