Solar Terrestrial Activity Report [Image] Last update June 4, 2000 at 02:10 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update June 2, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update June 2, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update June 2, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update April 12, 2000)] Recent development The geomagnetic field was quiet to unsettled on June 3. Solar wind speed ranged between 385 and 464 km/sec. A minor solar wind shock was observed at ACE at 08:05 UTC. The interplanetary magnetic field was later mostly northwards (with the exception of a moderate southward excursion at 10h UTC) resulting only in a minor increase in geomagnetic activity. It is uncertain if the source of the shock passage was the CME observed on May 31, if not that CME could still arrive during the first half of June 4. Solar flare activity was high. Solar flux was 165.9, the planetary A index was 12 (3-hour K indices: 3223 3333, Boulder K indices: 2223 2333). Region 9017 decayed significantly with the previously large trailing spot almost disappearing by the end of the day. Although the region has been quiet there is a chance of C flares occurring or perhaps even a minor M flare. Region 9022 decayed into spotless plage. Regions 9023 and 9024 were quiet and stable. Region 9026 developed further and has a strong magnetic delta configuration with several umbras of both polarities within the main penumbra. X class flares are possible, as are major proton flares. Region 9027 was quiet and stable. Region 9028 decayed into spotless plage. New region 9029 emerged near the northwest limb. New region 9030 emerged just to the southeast of region 9026. There appears to be another fairly interesting region at the northeast limb. Flares and CMEs A total of 9 C flares and 2 M flares were observed on June 3 with all optically events correlated to activity in region 9026. The region produced a C7.0 flare at 01:49, a C4.6 flare at 06:47, a C3.1/1B flare at 08:04, an M2.1/1F flare at 08:49, a C4.1 flare at 10:25, a C7.6 flare at 14:24, a C3.0 flare at 17:00, a major M6.1/2B flare at 19:24 and a C1.5 flare at 22:46 UTC. June 2: Region 9028 was the origin of a long duration C2.4 event peaking at 09:39 UTC. The flare may have been triggered by a filament eruption extending from the southern edge of the region to the solar equator. LASCO C3 images indicate a very weak full halo CME from approximately 10:30 UTC. This CME could impact Earth on June 5 but will likely not cause a significant disturbance, unsettled to active intervals are possible. Region 9026 produced a long duration major M7.6/2B flare peaking at 19:38 UTC. This event was associated with a very large and wide partial halo coronal mass ejection mainly off the east limb, however, there was material movement off all limbs and both poles and there is a chance Earth could receive a small impact sometime on June 5 or 6. May 31: A filament eruption was observed over the central meridian in the northern hemisphere starting at 06:48 UTC. A nearly full halo coronal mass ejection was observed in LASCO C2 images from 08:06 UTC, the only part of the disk where material motion was not detected was over the central west limb. A terrestrial impact is likely on June 3 or early on June 4. The background x-ray flux is at the class B6 level. Coronal holes A coronal hole in the southern hemisphere could rotate into a geoeffective position on June 5. Forecast The geomagnetic field is expected to be initially quiet to active on June 4-5. 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 9016 20000524 N26W83 plage 9017 20000524 12 S12W49 0480 CKO beta-gamma 9020 20000527 N04W87 plage 9021 20000528 N04W62 plage 9022 20000528 S22W16 plage 9023 20000529 5 S02W79 0020 BXO 9024 20000529 10 S12W17 0090 DSO 9026 20000601 17 N20E48 0910 EKO beta-gamma-delta 9027 20000601 3 N22W22 0010 BXO 9028 20000601 N08W01 plage 9029 20000603 4 N18W69 0010 BXO 9030 20000603 4 N11E58 0010 BXO Total number of sunspots: 55 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.04 117.2 63.9 85.5 (+1.7) 1999.05 148.4 106.3 90.5 (+5.0) 1999.06 169.8 137.7 93.1 (+2.6) 1999.07 165.6 113.5 94.5 (+1.4) 1999.08 170.7 93.7 97.4 (+2.9) 1999.09 135.7 71.5 102.3 (+4.8) 1999.10 164.8 116.7 107.7 (+5.4) 1999.11 191.5 133.2 110.9 (+3.2) 1999.12 169.8 84.6 (111.2 predicted, +0.3) 2000.01 158.1 90.2 (112.4 predicted, +1.2) 2000.02 174.1 112.3 (115.8 predicted, +3.4) 2000.03 208.2 138.2 (119.6 predicted, +3.8) 2000.04 184.2 125.3 (121.7 predicted, +2.1) 2000.05 184.9 120.8 2000.06 167.0 (1) 12.6 (2) 1) Running average based on the daily 20:00 UTC solar flux value at 2800 MHz.. 2) Unofficial, accumulated value. The official value 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 in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]