Solar Terrestrial Activity Report [Image] Last update October 26, 2001 at 03:05 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 to unsettled on October 25. Solar wind speed ranged between 358 and 508 km/sec. An unimpressive solar wind shock was observed at SOHO at 07:57 UTC. Solar wind speed increased abruptly from 380 to 490 km/sec. The source of the shock was the halo CME observed on October 22. Solar flare activity was high. Solar flux was 238.9, the planetary A index was 7 (3-hour K indices: 0022 2332, Boulder K indices: 0032 3221). Region 9669 decayed slowly, early on October 26 only one spot is visible. Region 9670 decayed significantly and was quiet. Region 9672 developed slowly and could produce further major flares. Multiple spots of both polarities are observed within the main penumbra. Region 9673 was quiet and stable, as were regions 9675 and 9676. Region 9677 decayed slowly and quietly. Region 9678 developed quickly and now has a magnetic delta structure in the north central section. The region was the largest on the visible disk by the end of the day. Major flares including X class flares are possible from this region over the next couple of days. Region 9679 was quiet and stable. New region 9681 emerged quickly in the southeast quadrant and is already capable of producing minor M class flares. New region 9682 at the northeast limb has a large main penumbra and could be capable of producing major flares. Flares and CMEs A total of 14 C and 1 X class events were recorded on October 25. Region 9678 generated a C4.8 flare at 03:31, a C5.7 flare at 07:48, a C7.5 flare at 19:23, a C4.4 flare at 20:49 and a C6.6 flare at 21:20 UTC. Region 9669 was the source of a C4.3 flare at 12:37 UTC. Region 9672 produced a C5.2 flare at 05:21, a C5.4 flare at 06:30 and a major long duration X1.3/2B event peaking at 15:02 UTC. This event was accompanied by a weak type II and a moderate (and long lasting) type IV radio sweep. A full halo CME was observed soon afterwards in LASCO C3 images. The CME will impact Earth, probably during the latter half of October 27 and could cause unsettled to major storm conditions. The background x-ray flux is at the class C1 level. Coronal holes A coronal hole in the northern hemisphere was in a geoeffective position on October 24-25. Forecast The geomagnetic field is expected to be quiet to unsettled on October 26 and most of October 27. Unsettled to major storm conditions are possible when the halo CME observed on October 25 arrives. 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 9667 2001.10.14 N27W74 plage 9669 2001.10.15 3 N14W68 0040 CSO 9670 2001.10.16 21 S19W47 0280 FAI beta-gamma 9671 2001.10.17 N16W75 plage 9672 2001.10.18 23 S18W27 0540 DKI beta-gamma-delta 9673 2001.10.18 5 N04W22 0100 CSO 9674 2001.10.19 S08W45 plage 9675 2001.10.20 3 S12E02 0020 CSO 9676 2001.10.20 2 N15E04 0040 HSX 9677 2001.10.21 6 N21E07 0030 DAO 9678 2001.10.23 35 N08E20 0300 EAI beta-gamma-delta 9679 2001.10.23 7 S11E35 0040 DSO 9680 2001.10.23 N22E35 plage 9681 2001.10.25 6 S25E05 0040 DSO 9682 2001.10.25 4 N09E70 0400 DKO Total number of sunspots: 115 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) 2001.10 203.1 (1) 154.0 (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]