SIDC Weekly Bulletin

:Issued: 2019 Mar 25 1443 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 951 from 2019 Mar 18
SOLAR ACTIVITY
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Solar activity was dominated by NOAA AR 2736, it was numbered on March 21
although it was already visible (northwest of the more quiet NOAA AR 2735)
at least one day earlier. By March 22 it had beta-gamma-delta magnetic
field configuration. It produced 13 C-class flares  and it was the source
of a halo CME on March 20 at 12:00 UT, mostly directed towards the
northwest but with an Earth directed component and a calculated speed of
750 km/s.
GEOMAGNETIC ACTIVITY
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Geomagnetic activity was quiet to unsettled throughout the week. On March
19 there were some signatures of the compression region in front of a high
speed stream from a positive polarity coronal hole. Nevertheless, the solar
wind speed never went above 420 km/s with also low interplanetary magnetic
field magnitudes (lower than 8 nT). In consequence, no geomagnetic storm
was observed. A flank of the CME from March 20 was calculated to arrive to
the Earth on March 23, but it was slowed down by the extremely slow solar
wind in front (with speeds around 260 km/s) and only a shock arrived on
March 24 at 20:43 UT.
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DAILY INDICES
DATE           RC   EISN  10CM   Ak   BKG    M   X
2019 Mar 18   ///    014   070   002   ////   0   0   
2019 Mar 19   017    016   070   010   A1.5   0   0   
2019 Mar 20   ///    037   077   005   A1.5   0   0   
2019 Mar 21   ///    039   080   002   A5.5   0   0   
2019 Mar 22   ///    031   082   000   B1.7   0   0   
2019 Mar 23   ///    025   079   001   B1.2   0   0   
2019 Mar 24   ///    016   075   002   A9.6   0   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 
NONE
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