There are currently 8 sunspot groups visible. NOAA 2157 seems to be slightly declining and simplifying. NOAA 2158 developed some small spots to the west and south of the main spot. Except for the northern part, this main spot is now completely surrounded by opposite magnetic polarity flux. Both NOAA 2157 and 2158 retained their delta structures. Two C-class flares and 1 M-class flare were recorded. The strongest event was a long duration M4.5 flare peaking at 00:29UT and originating in NOAA 2158. SDO/AIA-imagery indicated post-flare coronal loops, coronal dimming and an EIT-wave. A type II radio-burst with an associated shock speed of 999 km/s was observed. The greater than 10 MeV proton flux, currently still enhanced at 2 pfu, has not increased in response to this flare (so far). The M4.5 flare was associated to a halo CME first observed by SOHO/LASCO on 9 September at 00:06UT, with a plane-of-the-sky speed around 560 km/s . The bulk of the CME is directed away from the Earth (to the northeast), but there’s still a good chance Earth will be impacted by the CME-driven shock. Estimated impact time is 12 September at 03:00UT, with an uncertainty of 12 hours.
There remains a reasonable chance on an M-class flare. The warning condition for a proton event remains in effect.
Solar wind speed was mostly between 350 and 450 km/s, with Bz oscillating between +5 and -5 nT. Geomagnetic conditions were quiet.
Quiet to unsettled geomagnetic conditions are expected for the next three days, possibly modulated by the high speed stream from a coronal hole that passed the central meridian on 5 September. On 10 September, there’s a chance on unsettled conditions with an isolated active period in response to the possible glancing blow from the 6 September CME. On 12 September, the impact of the halo CME related to the M4.5 flare from 9 September may result in active conditions and possibly a brief period of minor
geomagnetic storming.
SIDC
Equipment: Coronado 90 + Imaging Source DMK + LX75
Processing: Photoshop, Avistack 300 frames
Date: 09/08/14
Time UT: 16:00
Exposure 1/500 sec.
Observatory Sponli
