Tag Archives: active regions

The Sun Online and solar activity. September 12, 2014

Over the last 24 hours, 2 M-class flares were produced by a currently unnumbered region at the northeast limb: an M2.1 flare peaking at 15:26UT, and an M1.4 flare peaking at 21:26UT. NOAA 2157 and 2158 produced 2 C-class flares each. The strongest was a C9.5 flare peaking at 02:24UT in NOAA
2157. Both of these regions have no longer a delta structure, but spots of opposite magnetic polarity are still close together. Based on the currently available imagery, no CMEs seem to have been associated to these flares. M-class flares are expected, with a chance on an X-class event.
On 11 September around 23:00UT, ACE observed a shock in the solar wind. Wind speed abruptly changed from about 350 to 480 km/s. Bz oscillated between -14 and +11nT. This was the arrival of the halo CME related to the M4-flare from 9 September. The impact resulted in active geomagnetic conditions (Dourbes), while Kp reached minor geomagnetic storm levels. Also the proton flux slightly increased. The arrival of the halo CME from the X1 flare is expected for later today. Pending the orientation of the CME’s magnetic field, this may result in a major geomagnetic storm, with locally severe geomagnetic storming possible.
SIDC

Equipment: Coronado 90 + Imaging Source DMK + LX75
Processing: Photoshop, Avistack 300 frames
Date: 12/08/14
Time UT: 16:00
Exposure 1/500 sec.

Observatory Sponli

The Sun Online and solar activity. September 9, 2014

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

The Sun Online and solar activity. September 8, 2014

There are currently 8 sunspot groups visible, with both NOAA 2157 and 2158 dominating the outlook of the solar disk. Five C-class flares were recorded, with the strongest a C7.8 flare peaking at 19:43UT. All C-class flares originated from active region NOAA 2157. No earth-directed CMEs were observed. The greater than 10 MeV proton flux is still enhanced, and currently at a steady 4 pfu. Both NOAA 2157 and 2158 have gained some sunspot area overnight, with magnetic delta structures prominently present.
There’s still a reasonable chance on an M-class flare. The warning condition for a proton event remains in effect.
On 8 September around 04:00UT, ACE observed a transient in the solar wind with wind speeds gradually increasing from a steady 340 km/s up to 430 km/s. The IMF continued pointing towards the Sun, with Bz evolving from an initial -3 nT towards its current +5 nT. Geomagnetic conditions remained 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.
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

The Sun Online and solar activity. September 4, 2014

Since yesterday’s bulletin, solar activity was on the C-level, with the strongest flare being the C5.2 flare peaking yesterday at 21:24 UT in the Catania sunspot group 44 (NOAA AR 1255) close to the east-south-east limb. The same active region yesterday produced the M2.5 flare that was accompanied only by a weak and narrow CME. The solar background X-ray flux is currently around the C1 level. We expect flaring activity up the M-level, in particular from the Catania sunspot group 44. The former
NOAA AR 2139 (that was responsible for the major eruption on the far side of the Sun on September 1) is now appearing from behind the east limb. The solar proton flux, although increased, has stabilized below the SEP event threshold. We maintain the warning condition for a proton event. The Earth is currently inside a slow (around 390 km/s) solar wind flow with average (around 5 nT) interplanetary magnetic field magnitude. The geomagnetic conditions are quiet and are expected to remain so.
SIDC

Equipment: Coronado 90 + Imaging Source DMK + LX75
Processing: Photoshop, Avistack 300 frames
Date: 09/04/14
Time UT: 16:00
Exposure 1/500 sec.

Observatory Sponli

The Sun Online and solar activity. September 3, 2014

A partial halo CME was detected yesterday in association with the eruption of a long filament in the northern hemisphere. The CME first appeared in the SOHO/LASCO C2 field of view at 16:36 UT, had angular width around 190 degrees and the projected plane-of-the-sky speed around 450 km/s. Despite
the position of the CME source region not far from the solar disk center, the bulk of the CME material went northward of the ecliptic plane. The arrival of the corresponding ICME and even of the ICME-driven shock at the Earth is unlikely, so no resulting geomagnetic disturbance is expected. This CME is a far side event as seen from Venus, so it will not affect Venus either.
SIDC

Equipment: Coronado 90 + Imaging Source DMK + LX75
Processing: Photoshop, Avistack 300 frames
Date: 09/03/14
Time UT: 16:00
Exposure 1/500 sec.

Observatory Sponli

The Sun Online and solar activity. August 27, 2014

Solar activity has decreased in the past 24 hours. Only a few C-class flares were observed, with NOAA ARs 2146, 2149 and 2151 as source regions. The largest flare was a C5.6 flare, peaking at 23:25 UT on August 26. No Earth-directed CMEs were observed. Flaring activity is expected to continue at the level of C-flares, with a slight chance for an isolated M-class flare. The risk for a proton event has reduced, but for the time being we leave the warning condition due to position of AR 2146 which still has a delta component.Solar wind observations indicate the arrival of an ICME around 0:00 UT of August 27, related to the CMEs of August 22. The magnitude of the magnetic field has smoothly increased from about 5 to 15 nT. The Bz component is southward with values up to -14 nT. Solar wind speed increased from 280 to 320 km/s, while there were only small variations in density and temperature. Geomagnetic conditions are currently unsettled (local K at Dourbes=3) to active (NOAA Kp=4), which is expect to persist for the next few hours, till quiet conditions return. The potential arrival of the August 25 CMEs might cause active conditions again from the UT afternoon of August 28 onwards.
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The Sun Online and solar activity. August 23, 2014

Solar activity was dominated by two C6 flares from NOAA AR 2146 and 2149. The first one, a C6.4 flare from NOAA AR 2149 peaked at 12:57 UT. The second one, a C6.2 flare from NOAA AR 2146 peaked at 15:52 UT. Flaring at C level is expected to continue with a fair chance for an M flare. Yesterdays C2.2 flare peaking at 10:27UT from NOAA AR 2146 was associated with type II radio bursts and with a CME visible in SOHO/LASCO C2 from 11:24 UT onwards. Despite the location of the source region near the
central meridian, the bulk of the mass was expelled in western direction from the sun earth line. The angular width was however underestimated by CACTUS, which due to the weaker additional north-eastern and south-eastern components is almost full halo. The projected speed is around 400 km/s. It was followed by a second partial halo CME first visible in SOHO/LASCO C2 images at 16:36 UT associated to the C6.2 flare peaking at 15:52 from the same region (NOAA AR 2146) and associated type II radio emission. The appearance of the second CME is roughly comparable with the first CME. A
dominant westward component with an additional north-eastern component, but now lacking the south-eastern component. A glancing blow from the combination of both CME’s may be expected around
UT midnight August 26/27.Solar wind conditions were nominal with speeds around 350 km/s (with a maximum of just over 380 km/s around 15:00 UT, and a minimum of just under 310 km/s around 8:30 UT). The total magnetic field is around 4.5 nT with a peak period of around 6 nT and a minimum of around
2 nT. Bz was variable within the +-4nT range. The phi angle was steadily in a positive (away) sector.
Geomagnetic conditions were quiet (both local K Dourbes and NOAA Kp in the 0-2 range). Over the next three days nominal solar wind conditions and quiet geomagnetic conditions are expected. Afterwards, near UT midnight 26/27 we may expect the impact of the August 22 CME’s.
SIDC

Equipment: Coronado 90 + Imaging Source DMK + LX75
Processing: Photoshop, Avistack 300 frames
Date: 08/23/14
Time UT: 16:00
Exposure 1/500 sec.

Observatory Sponli

The Sun Online and solar activity. August 20, 2014

There are 6 active regions on the visible side of the solar disk. Only NOAA AR 12146 (in NE quadrant) has shown a significant growth in the past 24 hours. We expect it will push up solar activity to C-class flaring levels, though further growth in size, complexity and thus flaring levels cannot be excluded. Note also that flaring activity is observed from behind the NE solar limb.Quiet geomagnetic conditions are expected in the coming 3 days: there are no high speed wind streams expected from coronal holes, nor are there any new CMEs on the way to the Earth. The arrival yesterday (Aug 19) of the Aug 15 CME resulted in a Kp=6 episode. The Bz component of the IMF has now turned fully Northward, thereby ending the geomagnetic storm.
SIDC

Equipment: Coronado 90 + Imaging Source DMK + LX75
Processing: Photoshop, Avistack 300 frames
Date: 08/20/14
Time UT: 16:00
Exposure 1/500 sec.

Observatory Sponli

The Sun Online and solar activity. August 18, 2014

Solar activity was low with only an isolated C1.8 flare peaking at 19:48UT from NOAA AR 2146 while NOAA AR 2144 continued to produce a couple of moderate to high level B class flares. No Earth directed CME’s were recorded.
Solar activity is expected to remain low with only a slight chance for an M class flare.Solar wind speed remained around the 300 km/s level. The reporting period was marked by a couple of sector boundary crossings. After a short excursion in the negative sector at the start of the reporting period, the phi angle restored to a positive sector. It was later steadily negative between approximately 20:00 UT and 5:00 UT, but is now again positive. These sector boundary crossings were associated with some magnetic field variabilities. A negative Bz of up to -6nT just before the reporting period was associated with unsettled geomagnetic conditions after UT noon August 17 (both NOAA Kp and local K Dourbes 3). Another local period of unsettled conditions was recorded around 9:00 UT (local K Dourbes 3). Nominal wind conditions, and corresponding quiet to unsettled geomagnetic conditions are expected to continue at first. But late August 19 some period of active conditions can be expected associated with the arrival of the August 15 CME.
SIDC

Equipment: Coronado 90 + Imaging Source DMK + LX75
Processing: Photoshop, Avistack 300 frames
Date: 08/18/14
Time UT: 16:00
Exposure 1/500 sec.

Observatory Sponli

The Sun Online and solar activity. August 17, 2014

No C flares were registered during the past 24 hours. In the next 48 hours, eruptive conditions (C flaring) are possible, especially from beta-gamma regions NOAA AR 2144 and 2139.Over the past 24 hours, solar wind speed as observed by ACE was stable around 280 km/s until it jumped to a plateau of
about 300 km/s around 23h UT on August 16. Meanwhile, the magnitude of the Interplanetary Magnetic Field (IMF) increased from about 2 to 8 nT. Over the past 24 hours, geomagnetic conditions were quiet (K Dourbes between 0 and 2; NOAA Kp between 0 and 2). Quiet geomagnetic levels (K Dourbes < 4)
are expected on August 17, 18 and 19. The expected arrival of the halo CME of August 15 at the end of August 19 may induce active geomagnetic conditions.
SIDC

Equipment: Coronado 90 + Imaging Source DMK + LX75
Processing: Photoshop, Avistack 300 frames
Date: 08/17/14
Time UT: 16:00
Exposure 1/500 sec.

Observatory Sponli

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