Mechanism behind solar flares revealed
Scientists have for the first time witnessed the mechanism behind explosive energy releases in the Sun's atmosphere, which has in turn confirmed new theories about how solar flares are created.
New footage put together by an international 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 discoveries of a gigantic energy build-up bring us a step closer to predicting when and where large flares will occur, which is crucial in protecting the Earth from potentially devastating space weather.
The paper's lead author, Dr. Jaroslav Dudik, Royal Society Newton International Fellow at the University of Cambridge's Center for Mathematical Sciences, said: "We care about this as during flares we can have CMEs and sometimes they are sent in our direction."
Knowing the standard scientific models are right is therefore very important. The standard 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.
In a smooth, none-entangled arc the magnetic energy levels are low but entanglement will occur naturally as the footpoints move about each other. Their movement is caused as they are jostled from below by powerful convection currents rising and falling beneath the photosphere.
As the movement continues the entanglement of field lines causes magnetic energy to build up.
Like a group of straight cords which has been twisted, the lines will hold the energy until it becomes too great and then will release it, "straightening" back to the lower energy state.
The study has been published in The Astrophysical Journal.
(Posted on 29-03-2014)