Watch a solar flare unfold in high resolution
They have the power to knock out GPS and communications systems on Earth, but solar flares are tricky to predict. New images provide valuable information in the life and demise of these burps of radiation from the Sun. Belinda Smith reports.
The Sun's surface is a turbulent mass of super-hot plasma and tangled magnetic fields that blast sudden bursts of radiation million of kilometres into space. Now, scientists have captured unprecedented images of one such solar flare, providing information about how energy is transferred between different regions of the Sun's surface.
Published in Scientific Reports by Ju Jing and her colleagues at the New Jersey Institute of Technology, US, the images of the enormous explosion include bright flare ribbons crossing a sunspot followed by "coronal rain", which showered the surface of the Sun with brilliant explosions.
"We can now observe in very fine detail how energy is transported in solar flares, in this case from the corona where it has been stored to the lower chromosphere tens of thousands of miles below it, where most of the energy is finally converted into heat and radiated away,” Ju says.
Sunspots are slightly cooler patches of the Sun's surface, so appear darker. But just because they're cooler, doesn't mean they're less active – in fact, it's the opposite.
Around midnight, UTC, on Sunday 17 April, a huge sunspot (big enough to fit almost five Earths inside) called Active Region 2529 blasted out what was deemed a "mid-level" solar flare, but still packed enough punch to disturb communications and GPS systems on Earth.
"Ever since a solar flare was first detected by Carrington and Hodgson in 1859, this spectacular phenomenon of solar activity has been a subject of intense research and has served as a natural laboratory for understanding the physical processes of transient energy release throughout the Universe," Ju and her colleagues write.
They tracked a solar flare on 22 June 2015 using the 1.6-metre New Solar Telescope at the Big Bear Solar Observatory in the San Bernardino Mountains, California.
By tracing its initial burst all the way through to its demise, the team was able to glean valuable information about all phases of the flare, including the instability of the magnetic flux tubes that trigger flares.
This information, they hope, will bridge the gap between models and observations, Ju says: "With large, ground-based telescopes, will we be able to measure, for example, these features on the Sun's surface down to their fundamental spatial scale?"
Hopefully, we will soon. Solar flares are difficult to predict, and even a few minutes' warning lets businesses shut down systems which may be affected.
Eventually, communication blackouts, such as the one following this month's solar flare, might be a thing of the past.
An early warning system for solar flares