Last major update issued on July 7, 2012 at 07:10 UTC.
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The geomagnetic field was quiet to active on July 6. Solar wind speed at SOHO ranged between 421 and 522 km/s..
Solar flux measured at 20h UTC on 2.8 GHz was 157.7 (increasing 29.4 over the last solar rotation and the highest flare unenhanced solar flux in 2012). The Potsdam WDC planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 15.4). Three hour interval K indices: 23222344 (planetary), 23322334 (Boulder).
The background x-ray flux is at the class C3 level.
At midnight UTC the visible solar disk had 11 spotted active regions (in 2K resolution SDO images).
Region 11513 [N15W65] was mostly quiet and unchanged.
Region 11515 [S17W52] is a large and complex region region with strong polarity intermixing and many magnetic delta structures. The region produced its first X class event which currently is associated with a minor proton event. Further major flare are possible and more significant proton flares are possible as the region approaches the southwest limb. Flares: C6.8/1N at 00:21, M2.9 at 01:40 C5.0/1N at 02:31, M1.0 at 02:51, C5.8 at 04:33, C7.4 at 07:07, M1.5 at 08:23, M1.8/1N at 10:29, M1.2 at 13:30, C5.0 at 16:05, C7.2 at 17:43, impulsive major X1.1 at 23:08 and M2.0 at 23:28 UTC. The X1.1 event was associated with a partial halo CME (in LASCO images, STEREO-A displays a full halo CME).
Region 11517 [N18W38] decayed slowly and quietly.
Region 11518 [N09E37] decayed slowly and quietly.
Region 11519 [S15E49] was quiet and stable.
Spotted active regions not numbered or interpreted differently by NOAA/SWPC:
S1767 [N20W50] decayed losing all but one spot. SWPC has decided that spotless AR 11516 suddenly moved northwards and assigned this spot to that AR.
S1769 [N17W21] decayed slowly and quietly.
S1775 [S18E74] rotated fully into view revealing a complex region with a huge central penumbra. That penumbra has a strong magnetic delta structure. X class flares are possible, however, this region is much less active flarewise than AR11515 and may release significantly more energy in the case of a major flare event. Flare: C7.7 at 04:59 UTC. This event was wrongly attributed to AR 11515 by SWPC, not surprising since they somehow managed to overlook this large region.
S1776 [S15E62] was quiet and stable.
S1777 [S13E76] was quiet and stable. This region can be interpreted as being part of AR S1775.
New region S1780 [S22W19] emerged with a few tiny spots and came close to developing rudimentary penumbra by the end of the day.
July 6: While the core CME associated with the X1 event in AR 11515 will
not reach Earth, a flank impact is likely on July 9.
July 5: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
July 4: A weak CME observed after an M1 flare in AR 11513 could reach Earth on July 7.
Coronal hole history (since October
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A coronal hole (CH522] in the northern hemisphere could rotate into an Earth facing position on July 6-7.
The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using this method, the extent and intensity of both CHs are consistent with other data sources.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is fair.
The geomagnetic field is expected to be quiet to active on July 7-8 with a chance of occasional minor storm intervals due to the recent CMEs from ARs 11515 and 11513. Unsettled to major storm is possible from the latter half of July 8 until July 10 due to effects from the CME observed after the X1 event in AR 11515 on July 6.
|Coronal holes (1)||Coronal mass ejection (2)||M and X class flares (3)|
1) Effects from a coronal hole could reach Earth within the
next 5 days. When the high speed stream has arrived the color changes to
2) Effects from a CME are likely to be observed at Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48 hours.
Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability.
Click on image for higher resolution image) Compare to the previous day's image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) is positive.
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.
|Active region||Date numbered
|Spot count||Location at midnight||Area||Classification||SDO / HMI 4K continuum
image with magnetic polarity overlay
SWPC has included AR S1767 in this region
|Total spot count:||71||159||69|
|Sunspot number:||131||269||159||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||99||202||112||(Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10)|
|Relative sunspot number (Wolf number):||79||94||87||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 (changed from 0.45 on March 1, 2011) for STAR SDO 2K, k = 0.55 for STAR SDO 1K|
|Month||Average measured solar flux||International sunspot number (SIDC)||Smoothed sunspot number||Average ap
|2008.07||65.7 (SF minimum)||0.5||2.8 (-0.4)|
|2012.01||132.5||58.3||(65.0 projected, +1.6)||7.15|
|2012.02||106.5||33.1||(66.5 projected, +1.5)||8.81|
|2012.03||114.7||64.2||(67.2 projected, +0.7)||16.08|
|2012.04||113.0||55.2||(66.5 projected, -0.7)||10.10|
|2012.05||121.5||69.0||(64.8 projected, -1.7)||7.06|
|2012.06||119.6||64.5||(64.0 projected, -0.8)||12.58|
|2012.07||146.2 (1)||26.5 (2A) / 136.7 (2B)||(65.0 projected, +1.0)||(17.56)|
1) Running average based on the daily 20:00 UTC observed solar flux value at
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official SIDC international sunspot number is typically 30-50% lower. 2B) Month average to date.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international Potsdam WDC ap indices.
This report has been prepared by Jan Alvestad. It is based on analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.
SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.