Solar Terrestrial Activity Report [Image] Last update May 10, 2002 at 03:40 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 unsettled on May 9. Solar wind speed ranged between 344 and 428 km/sec. There was no obvious solar wind shock but it appears as if the arrival of the CME observed on May 7 may have occurred at approximately 09:40 UTC. The interplanetary magnetic field was northwards for the remainder of the day after an initial confused state (which lasted until about 11h UTC) causing no increase in geomagnetic disturbance levels. Solar flare activity was low. Solar flux was 190.0, the planetary A index was 10 (3-hour K indices: 2233 3322, Boulder K indices: 2332 1312). Region 9931 rotated quietly over the northwest limb. Region 9932 was quiet and stable. Region 9933 decayed slowly and quietly. Region 9934 was mostly quiet. The two distinct parts of the region continued to develop independently of each other. The huge northern penumbra was mostly unchanged. The southern part of the region (having separate positive and negative magnetic areas as compared to the northern part of the region) developed quickly and early on May 10 has a magnetic delta structure. A major flare is possible. Region 9935 decayed and was spotless by early afternoon. Region 9936 decayed and became spotless early in the day. Region 9937 decayed further and was quiet. Region 9938 was quiet and stable. The combined region 9939/9940 decayed and had lost most of its spots by the end of the day. Region 9941 decayed slowly and could become spotless today. Region 9943 decayed and is spotless early on May 10. Region 9944 decayed and appeared to be spotless by the end of the day. Region 9945 developed slowly with the huge penumbra increasing in width. The region was quiet but is capable of M class flaring. Region 9946 (which could be part of region 9945) lost its magnetic delta structure and decayed. A large penumbra is early on May 10 rotating into view at the southeast limb. The positive and negative magnetic areas appear to be closely spaced and the magnetic gradients within the region could be tight. The region is still too close to the limb to allow a better evaluation of its flare potential. Flares and CMEs A total of 5 C class events were recorded on May 9. Region 9937 produced a C1.4 flare at 08:00 UTC. Region 9943 generated a C1.1 flare at 10:51 UTC. 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 B6 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled and May 10-12, possibly with a few active interval on May 11 due to a possible weak CME impact. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair to 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 S23W47 plage 9928 2002.04.29 N19W58 plage 9931 2002.05.01 1 N15W90 0060 HAX area too large 9932 2002.05.01 5 S27W46 0040 CAO 9933 2002.05.01 2 N18W41 0080 HSX 9934 2002.05.01 37 S16W32 0610 EKI two separate regions beta-gamma-delta 9935 2002.05.02 3 S19W64 0030 CSO now spotless 9936 2002.05.02 1 S16W54 0000 AXX now spotless 9937 2002.05.03 12 S08W11 0150 DAO 9938 2002.05.03 1 S05W08 0020 HSX 9939 2002.05.04 1 N19W01 0030 HSX same region as 9940 same region as 9939 9940 2002.05.04 14 N15E03 0080 DSO too high spot number and area 9941 2002.05.05 1 S22W44 0020 HSX 9942 2002.05.05 N21W16 plage 9943 2002.05.05 3 S10E11 0010 CSO now spotless 9944 2002.05.07 5 N08E09 0020 BXO now spotless 9945 2002.05.07 4 S05E40 0370 CKO 9946 2002.05.08 4 S06E52 0100 DAO 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) 2002.05 181.6 (1) 68.4 (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]