3D model reveals secret behind gigantic solar flares

In a first, scientists have witnessed the mechanism behind explosive energy releases in the sun's atmosphere - confirming new theories about how solar flares are created.

New footage put together by a team led by University of Cambridge researchers shows how entangled magnetic field lines looping from the sun's surface slip around each other and lead to an eruption 35 times the size of the earth and an explosive release of magnetic energy into space.

The discovery of a gigantic energy build-up brings us a step closer to predicting when and where large flares would occur which is crucial in protecting the earth from potentially devastating space weather.

Solar flares have long been a spectacular reminder of our star's power.

They are also associated with Coronal Mass Ejections (CMEs) - eruptions of solar material flying out of the sun and into interplanetary space.

"During solar flares, we can have CMEs and sometimes they are sent in our direction. The technology on earth is vulnerable to space weather. Indeed, CMEs can damage satellites and therefore have an enormous financial cost," explained Jaroslav Dudik, a Royal Society Newton International Fellow at University of Cambridge's centre for mathematical sciences.

These can also threaten airlines by disturbing the earth's magnetic field. Very large flares can even create currents within electricity grids and knock out energy supplies.

The new 3D model of solar flares has shown that they occur in places where the magnetic field is highly distorted.

In these places, the magnetic field lines can continuously reconnect while slipping and flipping around each other.

In doing so, new magnetic structures are created.

Long before the flare, the magnetic field lines are un-entangled and they appear in a smooth arc between two points on the photosphere (the sun's visible surface) - areas called field line footpoints.

As the movement continues, the entanglement of field lines causes magnetic energy to build up.

"You build the stress slowly until a point where they are no longer sustainable. The field lines say they have had enough and 'ping', they go back to something simple," said co-author Helen Mason, head of the atomic astro-physics group at University of Cambridge.

"That 'ping' creates the solar flare and CME," added the study published in The Astrophysical Journal.

Temperatures in the hotspots of the ejection can reach almost 20 million degrees Celsius.

The technology that created the 3D model is part of the Solar Dynamics Observatory (SDO) satellite mission launched in 2010 by NASA.