On 12 and 13 May, important eruptions took place in the southern portion of NOAA 2741. It concerned long-duration, low-level B-class events featuring large-scale coronal dimming and arcades (series of post-eruption coronal loops) - See these STCE newsitems for more examples of these features. The extreme ultraviolet images from SDO (AIA 193) underneath show both eruptions late on 12 May and during the afternoon of 13 May. The events were surprisingly impressive in view of the modest size and relative simple magnetic configuration of the source sunspot group.
Both eruptions were accompanied by coronal mass ejections (CMEs) likely containing an earth-directed component. They are not very obvious in SOHO's coronagraphic imagery (see underneath), but display very well in the above STEREO-A imagery (to the right) where the source region was nearly at the west limb (STEREO-A is currently about 90 degrees trailing the Earth - see the ST-A website). If the CMEs reach the earth environment (currently forecast for 16 and 17 May), geomagnetic activity may increase again, just as it did following the arrival of the last few interplanetary CMEs (ICMEs) generated by NOAA 2740.
