Solar Terrestrial Activity Report [Image] Last update June 5, 2000 at 04:50 UTC. Minor update posted at 10:44 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 active on June 4. Solar wind speed ranged between 408 and 573 km/sec. A solar wind shock was observed at 14:02 UTC at SOHO. The interplanetary magnetic field strengthened immediately and was mostly northwards until in the evening when moderate southward excursions occurred and caused the field to become active. The source of the disturbance is probably the halo CME observed on May 31. Solar flare activity was moderate. Solar flux was 169.7, the planetary A index was 12 (3-hour K indices: 2231 2344, Boulder K indices: 2231 1333). Region 9017 decayed further. Early on June 5 the region has only a single spot, a huge leader spot. Region 9023 rotated off the visible disk. Region 9024 was quiet and stable. Region 9026 was mostly unchanged and somewhat less active than it has been over the last few days. Further M class flares are likely and there is a possibility for an X class flare. Region 9027 was quiet and stable. Region 9028 reemerged with a single spot. Region 9029 was quiet and stable and will rotate over the west limb today. Region 9030 was quiet and stable. New region 9031 emerged in the southwest quadrant. A region just behind the northeast limb appears to be capable of M class flaring. Comment added at 10:44 UTC on June 5: An interesting filament eruption was observed starting at 03:12 UTC in LASCO EIT images. The eruption had its origin near region 9024 and spread eastwards almost to the central meridian. A partial halo coronal mass ejection was seen in LASCO C2 images from 04:06 UTC and covered parts of the southeast limb, the south pole, the southwest limb and the northwest limb. There should be a 50-60% chance of a terrestrial impact on June 8 with geomagnetic activity expected to range between unsettled and minor storm. Otherwise region 9031 has been developing quickly today and should be capable of C class flare production, minor M class flares could soon become possible if development continues. The region at the northeast limb has begun to rotate into view and appears to be a moderately large region. A disturbance arrived just after 05h UTC this morning and since then the interplanetary magnetic field has been moderately southwards resulting in increased geomagnetic activity, currently active to minor storm conditions are being observed. The source of the disturbance is probably the full halo CME observed during the first half of June 2. ACE solar wind parameters indicate that yet another CME is approaching Earth ... Flares and CMEs A total of 10 C flares and 1 M flare were observed on June 4. Region 9026 produced a C1.6 flare at 01:16, a C1.7 flare at 01:41, a C8.4 long duration event peaking at 04:36, a C3.1 flare at 06:30, a C1.7 flare at 09:51, a C3.6 flare at 13:18, a C1.8 flare at 20:18 and an M3.2 flare at 22:10 UTC. The latter flare triggered a filament eruption to the north of the region. 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. The background x-ray flux is at the class B7 level. Coronal holes A small coronal hole in the southern hemisphere could rotate into a geoeffective position on June 5 and cause a few unsettled to active intervals on June 8 or 9. Forecast The geomagnetic field is expected to be unsettled to minor storm on June 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 9017 20000524 6 S13W64 0410 CKO 9021 20000528 N04W75 plage 9022 20000528 S22W29 plage 9024 20000529 9 S11W31 0100 DSO 9026 20000601 27 N21E36 0870 FKI beta-gamma-delta 9027 20000601 1 N25W37 0000 AXX 9028 20000601 1 N10W14 0000 AXX 9029 20000603 3 N18W81 0020 CRO 9030 20000603 8 N10E44 0030 BXO 9031 20000604 4 S31W40 0050 DSO Total number of sunspots: 59 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 2000.06 167.7 (1) 17.3 (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]