Saturday Morning Fever...
posted: April 16, 2014

During the morning hours of Saturday 12 April, a flare took place near the Sun's southeast limb. It started at 07:15UT and reached its maximum (C5.0) at 07:27UT, then gradually decreased in intensity to end at 08:07UT. It occurred near the trailing part of NOAA 2035, which had shown some low level (C-class) flaring activity during the previous 2 days while rounding the east limb.


This movie shows the evolution of the flare and associated prominence eruption in successively hotter temperature bands: AIA 304 (80.000 degrees, transition region), AIA 171 (700.000 degrees, showing the upper transition zone/lower corona), and AIA 131. The latter is designed to show the hot parts in the corona, i.e. flares, and shows the solar atmosphere at several million degrees. AIA 131 also has a passband at around 400.000 degrees. That's why the relatively cool material of the ejected prominence is also somewhat visible in this filter.

The mosaic underneath shows some stills from this movie, taken at regular intervals and in the three SDO-filters. The flare itself is best and earliest visible in AIA 131 (hottest), whereas the series of post-flare coronal loops ("arcade") gradually become better visible in the cooler AIA 171 band. However, none of these filters can compete with the "cold" AIA 304 band when it comes to imaging the erupting prominence. Though material is clearly ejected, it can also be seen that material is returning to the solar surface along the magnetic field lines.


Aside the combination clip, the movie also contains coronagraphic imagery from SOHO/LASCO. The ejected material can be seen as a narrow coronal mass ejection with no Earth directed component. CACTUS indicates this CME had a speed near 500 km/s. The imagery also seems to show that some of the material which was already a few solar radii away from the Sun, eventually still returned to the solar surface. Indeed, it's not so easy to escape the Sunís gravity!


Credits - Data and imagery were taken from SDO, SOHO/LASCO, CACTUS, and (J)Helioviewer.