INFO FROM SIDC - RWC BELGIUM 2015 Apr 22 12:30UTC
Solar X-ray flaring activity reached moderate levels with a total of 5 M-flares, for which Catania group 28 (NOAA 2322) on the west limb was the most significant contributor. The largest flare was an M4.0 flare peaking at 15:45UT followed by an M2.1 flare peaking at 17:00UT, both from Catania group 28 (NOAA 2322). Later, in the decay phase of another M1.8 flare from that region peaking at 21:45UT a secondary peak of M1.2 magnitude at 22:01 UT is hard to attribute to any specific region. Finally, the region caused another M1.1 flare peaking at 8:44UT this morning.
Some further C flaring was observed mainly from Catania groups 32, 33 and 38 (respectively NOAA 2324, 2325 and 2327). The region on the eastern limb (now numbered Catania 44) which was the source of M flaring yesterday, remained remarkably silent today (apart from the eruptions described below). Field separation was observed in Catania group 37 (newly numbered NOAA 2331), as well as slight growth in Catania group 36 (newly numbered NOAA 2332) and Catania 38 (NOAA 2327). All other existing groups appeared stable or in decay. A number (6 in total) of additional small sunspot groups were numbered by Catania (39-43). With Catania group 28 departing behind the western limb, the most important source of M flaring is disappearing. Catania group 44 at the East limb still deserves to be monitored closely despite remaining quiet in the past 24 hours.
Hence C flaring is expected with a chance for M flaring remaining over the next days. Proton levels were at background values. A partial (asymmetric full) halo with primary north-east direction is visible in SoHO/LASCO C2 coronagraph images from 10:36 UT April 21 onwards. The event actually comprises of three consecutive events. At 10:25UT SDO/AIA images show a darkening at the north-east limb. The opening fieldlines appear to be originating from behind the limb. The consecutive post-flare arcades are visible at the limb and are the source of the M2.2 flare with peak time 10:40UT reported earlier. At 11:48 the SoHO/LASCO C2 coronagraph images show a second CME departing the west limb, again with no clearly identifiable on disc source although it appears to coincide with (though slightly preceding) the M2.2 flare observed from Catania group 28 (NOAA region 2322) close to the West limb. This second event is much less powerful than the first but could add to the apparent angular width.