Credit: NASA/ SDO/ University of Glasgow.
Movies of giant loops projecting from the surface of the Sun are giving new insights into the complex mechanisms that drive solar flares and Coronal Mass Ejections (CMEs).
These eruptions release vast energy and electrically charged particles that can affect the Earth through space weather.
Imagery from NASA's Solar Dynamics Observatory (SDO), used in two separate studies, shows the dynamics of loops before, during and after eruptions.
Results have been presented at the National Astronomy Meeting in St Andrews.
Coronal loops are giant magnetic arches filled with hot plasma at temperatures of over a million degrees Celsius.
The structures are anchored in the dense photosphere, the visible surface of the Sun. The loops form the building blocks of the corona, the halo surrounding the Sun that can be seen during a total eclipse.
They are dynamic structures that oscillate back and forth after explosive events such as solar flares.
Researchers from the University of Glasgow observed four groups of loops that contracted rapidly during a flare on 9 March 2012.
The loops had a 'staggered start' to their collapse, showing delays of 60–80 seconds from the inner to the outer loops.
"This event is a great example of a simultaneous implosion and explosion," said Dr Paulo Simões.
"Our interpretation is that energy is transferred from the magnetic field to power the flare, leaving a pocket of reduced magnetic support that causes an implosion.
The staggering between the loop contractions is caused by the time delay needed for the 'information' about the loss of support to travel outwards."
More information: R.S. White, E. Verwichte & C. Foullon, First observation of a transverse vertical oscillation during the formation of a hot post flare loop, A&A, 545, A129 (2012)
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