Solar Terrestrial Activity Report [Image] Last update May 11, 2002 at 04:40 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update May 3, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update May 3, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update May 3, 2002)] [Historical solar and geomagnetic data charts 1954-2002 (last update April 13, 2002)] Recent development The geomagnetic field was quiet to active on May 10. Solar wind speed ranged between 315 and 411 km/sec. A weak to moderate solar wind shock was observed at SOHO at 10:28 UTC. Solar wind speed increased abruptly from 330 to 410 km/sec. Solar flare activity was low. Solar flux was 191.0, the planetary A index was 17 (3-hour K indices: 2234 4434, Boulder K indices: 2233 3333). Region 9932 decayed and could become spotless later today. Region 9933 decayed slowly and quietly. Region 9934A (the northern part of region 9934) was quiet and stable, no significant changes were noted in or near the huge penumbra. Region 9934B (the southern part of region 9934) continued to develop early in the day, some minor decay was observed towards the end of the day. The region has at least two magnetic delta structures, one in the southeastern part of the largest penumbra, another one in a central penumbra. A major flare is possible. Region 9937 developed quickly and currently has a magnetic delta structure. An M class flare is possible. Region 9938 was quiet and stable. The combined region 9939/9940 decayed further and was quiet. Region 9941 decayed further and had only a very small spot left by the end of the day, the region is likely to become spotless soon. Region 9943 was once again spotless early in the day, only to reemerge with a few spots. Region 9945 developed slowly with the huge penumbra widening further. The region was quiet but is capable of M class flaring. Region 9946 developed slowly and could produce C flares. New region 9947 emerged in the northwest quadrant, but is already decaying and could soon become spotless. New region 9948 rotated into view at the southeast limb. The large penumbra has a magnetic delta structure. An M class flare is possible. Flares and CMEs A total of 11 C class events were recorded on May 10. Region 9946 produced a C4.0 flare at 00:39 and a C1.6 flare at 12:54 UTC. Region 9937 generated a C3.9 flare at 09:40, a C1.9 flare at 10:27 and a C1.6 flare at 14:32 UTC. Region 9934 became fairly active towards the end of the day and produced a C1.2 flare at 17:10, a C1.6 flare at 21:28, a C1.1 flare at 21:54 and a C3.3 flare at midnight. May 8: Region 9934 was the source of a long duration C4.2 event peaking at 13:27 UTC. A faint halo CME may have been associated with this LDE. This CME was first observed in LASCO C2 images at 13:50 UTC off the southwest limb and soon became a full halo CME. The CME was fairly slow and is not expected to reach the Earth until May 11. The background x-ray flux is at the class B9 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on May 11 and quiet to unsettled on May 12-13. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor. Coronal holes (1) Coronal mass M and X class flares (3) ejections (2) [Coronal hole indicator][CME indicator] [M and X class flare indicator] 1) Effects from a coronal hole could reach earth within the next 5 days. 2) Material from a CME is likely to impact 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. Active solar regions (Recent map) Solar Date Actual Location region numbered no. at Area Classification Comment sunspots midnight 9927 2002.04.29 S23W60 plage 9928 2002.04.29 N19W71 plage 9932 2002.05.01 1 S27W56 0020 HSX 9933 2002.05.01 1 N18W54 0060 HSX 9934 2002.05.01 32 S16W46 1050 EKI two separate regions beta-gamma-delta 9935 2002.05.02 S19W77 plage 9936 2002.05.02 S16W67 plage 9937 2002.05.03 20 S08W25 0190 DAO beta-gamma-delta 9938 2002.05.03 1 S05W21 0030 HSX 9939 2002.05.04 17 N19W12 0060 CSO same region as 9940 way too many spots 9940 2002.05.04 13 N17W11 0040 DSO same region as 9939 way too many spots 9941 2002.05.05 1 S22W58 0020 AXX 9942 2002.05.05 N21W29 plage 9943 2002.05.05 3 S10W03 0010 BXO 9944 2002.05.07 N08W04 plage 9945 2002.05.07 6 S04E27 0400 CKO 9946 2002.05.08 14 S06E38 0050 CSO 9947 2002.05.10 3 N23W46 0020 BXO 9948 2002.05.10 3 S21E71 0280 CHO beta-gamma-delta Total number of sunspots: 94 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.8 2001.04 177.7 107.7 107.5 (+2.7) 2001.05 147.1 96.6 108.6 (+1.1) 2001.06 173.0 134.0 109.8 (+1.2) 2001.07 131.3 82.2 111.7 (+1.9) 2001.08 162.9 106.8 113.6 (+1.8) 2001.09 233.2 150.7 114.1 (+0.5) 2001.10 207.6 125.5 114.0 (-0.1) 2001.11 210.6 106.5 (114.7 predicted, +0.7) 2001.12 235.1 132.2 (112.5 predicted, -2.2) 2002.01 226.6 113.9 (109.8 predicted, -2.7) 2002.02 205.0 108.0 (108.4 predicted, -1.4) 2002.03 179.5 98.1 (104.2 predicted, -4.2) 2002.04 189.8 120.4 (98.3 predicted, -3.9) 2002.05 182.5 (1) 76.3 (2) (93.8 predicted, -4.5) 1) Running average based on the daily 20:00 UT solar flux value at 2800 MHz. 2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-45% less. This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News]