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: 2024 Mar 29 1322 UTC
:Product: documentation at http://www.sidc.be/products/bul
#--------------------------------------------------------------------#
# SIDC Weekly bulletin on Solar and Geomagnetic activity             #
#--------------------------------------------------------------------#
WEEK 1212 from 2024 Mar 18

Solar Active Regions (ARs) and flares
---------------
Solar flaring activity reached very high levels on 23 Mar as an X1.1 flare
was registered at 01:33 UTC. It also reached high levels on 20 Mar as an M7
was detected at 07:36 UTC and on 24 Mar as nine M-class flares were
observed. The remaining days of the past week the flaring activity was at
moderate levels. In total 1 X-class flare and 25 M-class flares were
registered in the past week.
NOAA Active Region (AR) 3614 (magnetic configuration Beta, Catania sunspot
group 21) produced the X-class flare and only an M-class flare, an M1 on 18
Mar. Most of the M-class flaring activity was registered from NOAA 3615
(first with magnetic configuration Beta-Gamma and then Beta-Gamma-Delta,
Catania sunspot group 22), including an M7 flare on 20/3 07:36 UTC.

Coronal mass ejections
---------------------
A halo Coronal Mass Ejection (CME) was registered in LASCO-C2/SOHO images
on 23 Mar. It was associated with the X1.1 flare of the day from NOAA AR
3614. The ejecta was exceptionally fast and arrived on Earth's environment
on 24 Mar.

Coronal Holes
---------------------
A Coronal Hole (CH) with negative polarity crossed the solar central
meridian on 21 Mar.

Proton flux levels
---------------------
A major proton event took place starting from 23 Mar to the end of the
week. The greater than 10 MeV proton flux started increasing at 23 Mar
04:00 UTC and crossed the 10 pfu alert threshold level at 08:25 UTC the
same day. It became a major event when it crossed the 100 pfu threshold
level later that day at 14:10 UTC. It peaked twice, the first time at 23
Mar 18:25 UTC at 870 pfu and the second time at 24 Mar 12:25 UTC at 880
pfu, as measured by GOES 16. The flux dropped below the 100 pfu level at 24
Mar 19:45, but remain above the 10 pfu threshold for the rest of the past
week.

Electron fluxes at GEO
---------------------
The greater than 2 MeV electron flux, as measured by the GOES-16 satellite,
was bellow the 1000 pfu threshold throughout the past week. The 24h
electron fluence was at nominal levels during the same period.

Solar wind
---------------------
On 18 Mar the Solar Wind conditions registered a short-lived disturbance
that was either due to a stealth CME or a compression region caused by a
faster stream on the process of compressing a slower stream ahead of it.
The SW speed increased from 300 km/s to 400 km/s, the total interplanetary
magnetic field (Bt) varied between 2 nT and 11 nT, and its North-South
component (Bz) fluctuated between -11 nT and 5 nT. The interplanetary
magnetic field phi angle was directed both towards and away from the Sun
during the disturbance.
The conditions returned to the slow SW regime the next day only to be
excited again with the arrival of a CME on 21 Mar that lasted until 22 Mar
17:30 UTC. The SW speed increased again from 300 km/s to 400 km/s, Bt
varied between 1 nT and 15 nT, and Bz fluctuated between -12 nT and 11 nT.
The interplanetary magnetic field phi angle was directed both towards and
away from the Sun during the same period.
A High Speed Stream (HSS), associated with the CH crossing of the 21 Mar,
arrived later the same day (22 Mar 23:00 UTC). It caused the SW speed to
increase to 500 km/s, while Bt was constant at 10 nT and Bz at 5 nT. The
interplanetary magnetic field phi angle was directed away from the Sun
during the event.
A fast forward shock ahead of the halo CME of 23 Mar reached the Earth's
environment at 24 Mar 14:11 UTC. The solar wind speed jumped from 628 km/s
to 821 km/s and the Bt jumped from 11 nT to 17 nT and started to fluctuate
reaching a maximum value of 34 nT at 24 Mar 16:05 UTC. Initially, between
14:30 and 15:50 UTC, the Bz component was mostly negative with a minimum
value of -27 nT and then from 15:50 UTC turned mostly positive. The Bt
started to decrease slowly from 31 nT at 19:30 UTC.  After the initial
shock, the solar wind speed increased further and reached a maximum value
of 880 km/s at 24 Mar 18:21 UTC and remained above 800 km/s for the rest of
the day.

Geomagnetism
---------------------
At the start of the past week, geomagnetic conditions were globally and
locally quiet to unsettled (NOAA Kp 0+ to 3+ and K BEL 1 to 3) until the
arrival of the CME of 21 Mar. 
Minor storm conditions were registered globally (NOAA Kp 5 at 12:00-18:00
UTC and Kp 5- at 18:00-21:00 UTC) as a result, but during the same period
the local conditions only reached active to unsettled levels (K BEL 4 at
12:00-18:00 UTC and at 21:00-24:00 UTC). 
The conditions went back to quiet to unsettled levels globally (NOAA Kp 1+
to 3-) from 22 Mar 03:00 UTC to 23 Mar 03:00 UTC, while locally the quiet
to unsettled levels (K BEL 1 to 3) lasted from 22 Mar 00:00 UTC to 23 Mar
12:00 UTC.
A new period of globally minor storm conditions started at 23 Mar 03:00 UTC
(NOAA Kp 5 03:00-06:00 UTC, 5- 06:00-09:00 UTC  and 18:00-21:00 UTC) that
reached the moderate storm level (NOAA Kp 6-) at 21:00-24:00 UTC and
dropped to minor storm (NOAA Kp 5-) at 24 Mar 00:00-03:00 UTC. Locally
minor storm conditions (K BEL 5) where only observed that day during the
18:00-24:00 UTC period.
The arrival of the fast halo CME on 24 Mar caused a further major increase
to the geomagnetic conditions. At the global level, moderate storm
conditions were first registered (NOAA Kp 6 at 12:00-15:00 UTC), which
increased to the severe storm level (NOAA Kp 8) for a short period
(15:00-18:00 UTC) as they fast subsided to moderate storm (NOAA Kp 6+) at
18:00-21:00 UTC and active levels (NOAA Kp 4) at 21:00-24:00 UTC. At the
local level, minor storm conditions (K BEL 5) were recorded at 12:00-15:00
UTC, that were increased to major storm (K BEL 7) at 15:00-18:00 and then
were reduced to minor storm conditions (K BEL 5) at 18:00-21:00 UTC.

---------------------------------------------------------------------------
DAILY INDICES
DATE           RC   EISN  10CM   Ak   BKG    M   X
2024 Mar 18   147    123   177   005   C1.3   3   0   
2024 Mar 19   168    135   169   008   C1.3   2   0   
2024 Mar 20   147    126   176   006   C1.4   2   0   
2024 Mar 21   219    166   197   022   C1.7   0   0   
2024 Mar 22   ///    160   198   012   C2.2   2   0   
2024 Mar 23   ///    159   209   033   C4.3   13   1   
2024 Mar 24   ///    166   195   062   C2.7   9   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 
18  0321  0332 0345 ////// M2.7          15/3612      III/1 

18  0406  0414 0424 ////// M1.0          21/3614      

18  1902  1919 1928 ////// M6.7          ///3615      

19  0224  0229 0238 ////// M1.4          22/3615      

19  2317  2327 2332 S16E57 M2.1 SN       22/3615      

20  0723  0736 0747 S10E51 M7.4 3B       22/3615      

20  2246  2255 2300 ////// M1.9          22/3615      

22  2018  2032 2045 S13E22 M4.2 2B       22/3615      

22  2120  2122 2125 S14E18 M1.1 SN       22/3615      

23  0058  0133 0221 N27E08 X1.1 2F       21/3614      VI/2CTM/1II/2 

23  0647  0655 0659 S13E04 M1.1 SF       22/3615      

23  0701  0709 0726 ////// M2.4          22/3615      

23  0726  0738 0747 ////// M3.1          22/3615      

23  1122  1129 1136 S15E10 M1.0 SF       22/3615      CTM/1 

23  1236  1247 1256 S15E09 M1.3 1B       22/3615      

23  1304  1311 1320 ////// M1.1          22/3615      

23  1331  1337 1344 ////// M1.9          22/3615      III/2 

23  1351  1402 1415 ////// M5.3          22/3615      

23  1449  1453 1458 ////// M1.5          22/3615      

23  1501  1513 1517 ////// M3.8          22/3615      

23  1517  1522 1527 ////// M3.7          ///////      

23  1622  1651 1707 ////// M2.8          22/3615      

23  2330  2349 0003 S12E01 M2.4 2N       22/3615      

24  0112  0125 0130 ////// M1.4          22/3615      

24  0143  0154 0157 S14W00 M2.1 2N       22/3615      

24  0157  0205 0209 ////// M2.3          22/3615      CTM/1 

24  0209  0218 0229 ////// M2.7          22/3615      

24  0559  0606 0610 S14W03 M2.2 1B       22/3615      

24  0736  0751 0806 S14W03 M1.3 2N       22/3615      III/1 

24  1210  1218 1222 S14W05 M1.1 1N       22/3615      

24  1227  1234 1239 S13W07 M1.0 SF       22/3615      

24  1300  1313 1328 ////// M1.2          22/3615      CTM/1 

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Details

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.