SIDC Weekly Bulletin
Review of past solar and geomagnetic activity.| Source | SIDC (RWC-Belgium) |
| Frequency | Weekly |
| Format | Plain text |
| Mail header | SIDC Weekly Bulletin |
| SIDC code | bul |
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:Issued: 2025 Apr 14 1526 UTC :Product: documentation at http://www.sidc.be/products/bul #--------------------------------------------------------------------# # SIDC Weekly bulletin on Solar and Geomagnetic activity # #--------------------------------------------------------------------# WEEK 1267 from 2025 Apr 07 Solar Active Regions (ARs) and flares --------------- The solar flaring activity over started at low levels and increased to high levels at the end of the week. A total of 20 active regions were numbered on the visible solar disk with SIDC Sunspot Group 461 (NOAA Active Region 4048) and SIDC Sunspot Group 469 (NOAA Active Region 4055) being the most notable. These regions were the largest and most complex ones (classified as magnetic type beta-gamma-delta) contributing to most of the flaring activity throughout the week. The strongest activity registered was an M2.7 flare, SIDC flare 4099, with peak time 11:45 UTC on April 12, produced by SIDC Sunspot Group 469. Coronal mass ejections --------------------- Multiple filament were observed throughout the week with two major eruptions, resulting in coronal dimming and Earth-directed coronal mass ejections (CMEs). A wide slow south-eastward CME was observed in the LASCO/C2 imagery around 23:36 UTC on April 12. The CME had a projected velocity around 300 km/s and is associated with a long filament crossing the central meridian to the east of the disk center, which erupted around 23:00 UTC on April 12. A faster partial halo CME with estimated projected velocity around 550 km/s was observed in the LASCO/C2 data starting at 07:12 UTC on April 13. The CME is related to a neighbouring filament eruption to the south of SIDC Sunspot Group 398 (NOAA Active Region 4056). Both CMEs are expected to arrive at Earth in a combined shock arrival in the upcoming week. Coronal Holes --------------------- Three negative polarity and two small and compact positive-polarity coronal holes have have crossed the central meridian throughout the week. High speed streams related to the negative polarity coronal holes were detected at Earth throughout the week. Proton flux levels --------------------- The greater than 10 MeV GOES proton flux was at nominal levels throughout the entire week. Electron fluxes at GEO --------------------- The greater than 2 MeV electron flux as measured by GOES 18 was above the 1000 pfu threshold for prolonged periods throughout the entire week. The corresponding electron fluence started at high levels and reduced to moderate levels for the rest of the week. Solar wind --------------------- The solar wind conditions throughout the week reflected several high speed stream (HSS) arrivals. The magnitude of the interplanetary magnetic field (B) reached a maximum value of 11.5 nT with a minimum Bz of -11.3 nT. The B field phi angle was predominantly in the negative sector (directed towards the Sun) throughout the entire week reflecting the polarity of the geo-effective coronal holes. The solar wind speed varied in the range of 358 km/s to 724 km/s. Geomagnetism --------------------- The geomagnetic conditions throughout the week varied between quiet to minor storm levels. Locally over Belgium mostly quiet to active conditions were observed with a short isolated minor storm level registered late on April 08. --------------------------------------------------------------------------- DAILY INDICES DATE RC EISN 10CM Ak BKG M X 2025 Apr 07 /// 150 162 018 C1.3 0 0 2025 Apr 08 148 138 159 023 C1.6 1 0 2025 Apr 09 182 135 167 016 C1.6 0 0 2025 Apr 10 155 132 153 018 C1.0 0 0 2025 Apr 11 148 125 170 016 C1.4 2 0 2025 Apr 12 /// 115 165 019 C3.1 7 0 2025 Apr 13 /// 098 164 013 C4.1 10 0 --------------------------------------------------------------------------- # RC : Sunspot index (Wolf Number) from Catania Observatory (Italy) # EISN : Estimated International Sunspot Number # 10cm : 10.7 cm radioflux (DRAO, Canada) # Ak : Ak Index Wingst (Germany) # BKG : Background GOES X-ray level (NOAA, USA) # M,X : Number of X-ray flares in M and X class, see below (NOAA, USA) --------------------------------------------------------------------------- NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM Catania/NOAA RADIO_BURST_TYPES 08 2208 2222 2236 S15W52 M1.5 1B 19/4048 11 1640 1650 1701 ////// M1.0 26/4055 11 2208 2220 2233 N07W50 M1.0 SF 26/4055 12 0441 0445 0455 ////// M1.1 26/4055 12 0536 0549 0555 N05W57 M1.2 SF 26/4055 12 0711 0719 0722 N06W56 M1.0 SF 26/4055 12 1105 1117 1125 ////// M2.0 26/4055 12 1135 1143 1145 ////// M2.7 26/4055 12 1233 1240 1252 ////// M2.3 26/4055 12 1500 1512 1519 N07W61 M1.3 SF 26/4055 13 0121 0129 0137 ////// M1.0 26/4055 13 0401 0405 0425 ////// M1.1 26/4055 13 0425 0428 0431 ////// M1.1 26/4055 13 0448 0452 0454 N07W69 M2.3 SF 26/4055 13 0638 0652 0721 N07W67 M1.0 S 26/4055 III/1 13 0943 0955 1003 N06W73 M1.4 1 26/4055 13 1003 1007 1010 ////// M1.2 26/4055 13 1528 1542 1556 ////// M1.2 26/4055 13 1838 1851 1900 ////// M3.2 26/4055 13 2155 2202 2211 N09W77 M1.6 1F 26/4055 #--------------------------------------------------------------------# # Solar Influences Data analysis Center - RWC Belgium # # Royal Observatory of Belgium # # # # Website http://www.sidc.be. # # E-mail sidc-support@oma.be # # To unsubscribe http://www.sidc.be/registration/unsub.php # # # # Legal notices: # # - Intellectual Property Rights: # # http://www.astro.oma.be/common/internet/en/data-policy-en.pdf # # - Liability Disclaimer: # # http://www.astro.oma.be/common/internet/en/disclaimer-en.pdf # # - Use and processing of your personal information: # # http://www.astro.oma.be/common/internet/en/privacy-policy-en.pdf # #--------------------------------------------------------------------#
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This report is sent once a week, typically on a monday.The weekly bulletin gives an overview of solar and geomagnetic activity of the past week and includes a noticeable solar events list.
Check the ISES code book for information on ISES codes.