In most cases, the appearance of the flare ribbons in the solar atmosphere is related to the rising and eruption of a solar filament. This can occur suddenly. EST will help to understand this rapid phenomenon, writes Dr. Francesca Zuccarello from University of Catania (Italy).
In most cases the appearance of the flare ribbons in the solar atmosphere is related to the rising and eruption of a solar filament. Filaments (or prominences when observed at the solar limb) are plasma condensations characterized by a lower temperature and a higher density with respect to the surrounding atmosphere. They are located along the polarity inversion line that separates opposite magnetic polarities.
The movie shows the development of ribbons in the chromosphere and the eruption of a (dark) filament during a flare that occurred on 7 November 2014. In turn, the eruption of a filament can be associated with coronal mass ejections (CMEs) that will propagate in the interplanetary space and, in some circumstances, can affect the Earth’s magnetic field and cause aurorae.
The sequence “filament eruption – flare – CME” can occur suddenly: a filament that was quietly sitting in an active region for hours/days gets destabilized and erupts in a few tens of minutes. Many models have been considered to explain these phenomena (mainly involving magnetic reconnection), but in order to really understand what can cause such rapid and sudden phenomena, we need a telescope with a large aperture, like the 4-m European Solar Telescope!