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 Jul 01 2140 UTC :Product: documentation at http://www.sidc.be/products/bul #--------------------------------------------------------------------# # SIDC Weekly bulletin on Solar and Geomagnetic activity # #--------------------------------------------------------------------# WEEK 1278 from 2025 Jun 23 Solar Active Regions (ARs) and flares --------------- Solar flaring activity was low over the past week, with only C-class flares identified. The largest flare was a C5.0 flare (SIDC Flare 4739) peaking at 12:23 UTC on June 23, which was produced by SIDC Sunspot Group 523 (NOAA Active Region 4114). During the flare, the source region (SIDC 523) of the flare had beta configuration of its photospheric magnetic field. There were 16 numbered active regions on the visible solar disk throughout the week. SIDC Sunspot Groups 527 and 530 (NOAA Active Regions 4118 and 4120) were the most complex regions with their beta-gamma magnetic configurations. At the end of the week, 10 sunspot groups were visible on the solar disk. Coronal mass ejections --------------------- Narrow coronal mass ejections (CME) were observed on NW limb in SOHO/LASCO-C2 on Jun 25 and Jun 27. They were associated with filament eruptions on NW quadrant of the Sun, which was part of an extended filament in the northern hemisphere. These CMEs did not arrive at Earth. A partial halo CME was observed in SOHO/LASCO-C2 images around 21:00 UTC on Jun 28 with a projected speed of about 500 km/s. It was associated with the C4.0 flare (SIDC Flare 4771, N06 W21, peaked at 19:54 UTC on June 28) produced by SIDC Sunspot Group 537 (NOAA Active Region 4126). Coronal Holes --------------------- At the beginning of the past week, recurrent negative polarity coronal hole (SIDC Coronal Hole 116) which spanned from 20 S to 30 N crossed the central meridian during Jun 21-25. A CIR and following high speed streams related to this coronal hole enhanced the solar wind parameters near Earth during Jun 25-29. Another recurrent negative polarity coronal hole (SIDC Coronal Hole 111) which spanned from 20 to 40 S started to cross the central meridian on Jun 29. 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-19, briefly exceeded the 1000 pfu alert threshold level daily until Jun 25. The greater than 2 MeV electron flux, as measured by GOES-18 satellite, was above the threshold levels daily for few hours until Jun 25. Both the electron fluxes were below the threshold level on Jun 26. From Jun 27, the greater than 2 MeV electron flux, as measured by GOES-19 and GOES-18 satellites, remained above the 1000 pfu threshold level during most of the time. This was due to the high solar wind speed associated with the SIDC Coronal Hole 116 which crossed the central meridian during Jun 21-25. Solar wind --------------------- At the beginning of the past week, the solar wind parameters were transitioning from fast to slow solar wind until Jun 24. A CIR and following high speed streams (HSSs), related to the negative-polarity coronal hole (SIDC Coronal Hole 116) that crossed the central meridian during Jun 21-25, enhanced the solar wind parameters near Earth during Jun 25-29. During the entire past week, the solar wind speed ranged from 355 km/s to 850 km/s. The North-South component (Bz) ranged between -12 nT and 14 nT. The interplanetary magnetic field ranged between 1 nT and 17 nT. Geomagnetism --------------------- At the start of the past week, geomagnetic conditions were at quiet to unsettled conditions (NOAA Kp and K_BEL 1 to 3) both globally and locally. With the arrival of high speed streams (HSSs) associated to the negative-polarity coronal hole (SIDC Coronal Hole 116) that crossed the central meridian during Jun 21-25, geomagnetic conditions were globally at unsettlled to minor storm conditions (NOAA Kp 3 to 5) during Jun 25-27, and locally it was at unsettled to active conditions (K_BEL 3 to 4). At the end of the past week, geomagnetic conditions were at quiet to unsettled conditions (NOAA Kp and K_BEL 1 to 3) both globally and locally. --------------------------------------------------------------------------- DAILY INDICES DATE RC EISN 10CM Ak BKG M X 2025 Jun 23 143 094 122 009 B6.7 0 0 2025 Jun 24 089 085 120 013 B6.0 0 0 2025 Jun 25 113 096 117 016 B4.8 0 0 2025 Jun 26 100 105 117 031 B4.9 0 0 2025 Jun 27 114 118 118 024 B5.1 0 0 2025 Jun 28 /// 137 122 011 B5.1 0 0 2025 Jun 29 /// 152 128 010 B6.3 0 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 NONE #--------------------------------------------------------------------# # 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.