Solar Terrestrial Activity Report [Image] Last update October 18, 2001 at 03:10 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update October 3, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update October 3, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update October 3, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update October 16, 2001)] Recent development The geomagnetic field was quiet on October 17. Solar wind speed ranged between 297 and 365 km/sec. Solar flare activity was moderate. Solar flux was 217.4, the planetary A index was 4 (3-hour K indices: 2111 2222, Boulder K indices: 2111 2122). New flux emerged in the central part of region 9658 and a magnetic delta structure developed. The region could produce further minor M class flares. Region 9659 decayed and was spotless by late evening. Region 9661 developed slowly. The positive and negative polarity spots making up the strong magnetic delta structure in the main penumbra have moved closer resulting in a significant increase in magnetic shear. A very large proton flare (possibly class X10+) could be observed anytime over the next couple of days. Region 9662 decayed slowly and quietly. Region 9663 decayed slowly and quietly and was spotless early on October 18. Region 9667 was quiet and stable. Region 9669 developed slowly and could produce minor M class flares. Region 9670 was quiet and stable, occasional minor M class flares are possible. New region 9671 emerged in the northeast quadrant. A new region has rotated into view at the southeast limb and should be numbered today. Flares and CMEs A total of 5 C and 1 M class events were recorded on October 17. Region 9661 produced a C3.5 flare at 07:21 and a C2.5 flare at 17:21 UTC. Region 9658 generated an M1.1 flare at 11:23 UTC. Region 9659 was the source of a C3.9 flare at 16:21 UTC. The background x-ray flux is at the class C2 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on October 18-19. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair. 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 9655 2001.10.06 S22W76 plage 9657 2001.10.08 N22W49 plage 9658 2001.10.09 12 S15W35 0150 FAO beta-gamma-delta 9659 2001.10.10 2 N05W75 0020 BXO 9660 2001.10.10 N13W62 plage 9661 2001.10.10 28 N16W08 0800 FKI beta-gamma-delta 9662 2001.10.11 10 N10W37 0070 CSO 9663 2001.10.11 1 S16W17 0010 AXX 9664 2001.10.12 N07W49 plage 9666 2001.10.14 S11W08 plage 9667 2001.10.14 5 N25E35 0070 DAO 9668 2001.10.15 N29W25 plage 9669 2001.10.15 14 N13E42 0140 EAO beta-gamma 9670 2001.10.16 4 S18E59 0340 FAO 9671 2001.10.17 5 N15E32 0020 BXO Total number of sunspots: 81 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 2000.09 182.1 109.7 116.3 (-2.3) 2000.10 167.4 99.4 114.5 (-1.8) 2000.11 178.8 106.8 112.7 (-1.8) 2000.12 173.6 104.4 112.0 (-0.7) 2001.01 166.6 95.6 108.7 (-3.3) 2001.02 146.6 80.6 104.1 (-4.6) 2001.03 177.7 113.5 104.8 (+0.7) 2001.04 177.7 107.7 (107.7 predicted, +2.9) 2001.05 147.1 96.6 (108.1 predicted, +0.4) 2001.06 173.0 134.0 (106.3 predicted, -1.8) 2001.07 131.3 82.2 (105.1 predicted, -1.2) 2001.08 162.9 106.8 (105.7 predicted, +0.6) 2001.09 233.2 150.7 (105.1 predicted, -0.6) 2001.10 187.9 (1) 97.5 (2) (102.3 predicted, -2.8) 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 25-40% 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]