SIDC Weekly Bulletin

:Issued: 2024 Apr 15 1213 UTC
:Product: documentation at http://www.sidc.be/products/bul
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# SIDC Weekly bulletin on Solar and Geomagnetic activity             #
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WEEK 1215 from 2024 Apr 08

Solar Active Regions (ARs) and flares
---------------
Solar flaring activity was low between April 8th-11th, with multiple
C-class flares. Solar flaring activity reached moderate levels towards the
end of the week, with three M-class flares. The strongest flare was an M5.4
from beyond the east solar limb, peaking at 17:06 UTC on April 11th. There
was a total of 11 numbered active regions observed on the visible solar
disk over the week. The most complex one was NOAA AR 3634, which evolved
from beta to beta-gamma and back to beta.

Coronal mass ejections
---------------------
A faint Coronal Mass Ejection (CME) from the south-east was observed in
SOHO/LASCO-C2 around 06:30 UTC on April 11th, likely associated with a
filament eruption near the central meridian. A faint partial halo coronal
mass ejection (CME) was observed in SOHO/LASCO-C2 and SOHO/LASCO-C3
starting from 02:30 UTC on April 12th. It was probably associated with the
filament eruption observed in SDO/AIA 304 data at 01:10 UTC on April 12th.
A faint Coronal Mass Ejection (CME) from the north was observed in
SOHO/LASCO-C2 around 18:30 UTC on April 13th. It was probably associated
with a C5.5 flare from NOAA AR 3634. A CME from the north-west limb was
observed in SOHO/LASCO-C2 and SOHO/LASCO-C3 starting from 03:50 UTC on
April 14th. It is possibly related to a prominence eruption on the west
limb.

Coronal Holes
---------------------
Two small coronal holes have crossed the central meridian during the past
week. The first one was a negative polarity, equatorial, south coronal hole
that crossed the central meridian on April 9th. The second one was a
positive polarity, mid-latitude, north coronal hole that crossed the
central meridian on April 10th.

Proton flux levels
---------------------
The greater than 10 MeV GOES proton flux was below the 10 pfu threshold
over the past week.

Electron fluxes at GEO
---------------------
Over the past week, the greater than 2 MeV electron flux remained below the
1000 pfu threshold as measured by GOES 16. The greater than 2 MeV electron
flux measured by the GOES-18 satellite reached the threshold between 17:50
UTC and 23:30 UTC on April 7th. The 24-hour electron fluence was at nominal
levels throughout the week.

Solar wind
---------------------
Over the past week, slow solar wind conditions were observed with speed
values between 300 km/s and 510 km/s. The interplanetary magnetic field
varied between 5 nT and 8 nT. The Bz component varied between -7 nT and 7
nT. The interplanetary magnetic field phi angle was predominantly in the
positive sector.

Geomagnetism
---------------------
Geomagnetic conditions locally and globally were at quiet to unsettled
levels (NOAA Kp and K BEL from 0 to 3).

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DAILY INDICES
DATE           RC   EISN  10CM   Ak   BKG    M   X
2024 Apr 08   110    073   125   006   B3.4   0   0   
2024 Apr 09   072    058   124   010   B3.8   0   0   
2024 Apr 10   069    055   131   009   B6.1   0   0   
2024 Apr 11   096    089   144   006   B9.3   1   0   
2024 Apr 12   084    080   152   005   C1.5   0   0   
2024 Apr 13   ///    120   161   006   C1.2   1   0   
2024 Apr 14   ///    139   178   006   C1.6   1   0   
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# 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)
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NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX  END  LOC    XRAY OP  10CM Catania/NOAA RADIO_BURST_TYPES 
11  1652  1706 1711 ////// M5.4          ///////      III/2IV/1 

13  0458  0502 0506 S10E80 M2.4 SF       ///3637      III/2 

14  0224  0232 0236 S11E67 M4.3 1F       ///3637      III/3 

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