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: 2017 Apr 25 0710 UTC
:Product: documentation at http://www.sidc.be/products/bul
#--------------------------------------------------------------------#
# SIDC Weekly bulletin on Solar and Geomagnetic activity             #
#--------------------------------------------------------------------#
WEEK 851 from 2017 Apr 17
SOLAR ACTIVITY
---------------
The week started with NOAA AR 2651 rotating over the east limb and
producing 3 C-class flares, the strongest one was a C5.5 on 18 April at
20:10 UT. This region presented a beta-gamma magnetic field configuration
but then decayed into beta configuration on April 20 and did not produce
any more flares after that. Other two ARs were present, NOAA ARs 2652 and
2653 but did not produce any activity. The C5.5 flare was related to a
partial halo CME with speeds of around 900 km/s directed towards the east.
GEOMAGNETIC ACTIVITY
---------------------
On April 19-20 the high speed stream from an equatorial (positive) coronal
hole arrived to the Earth. The solar wind speed raised to 600 km/s with
interplanetary magnetic fields of 15 nT. It produced major storm at
planetary levels (Kp = 6) and active conditions locally at Dourbes (K = 4).
On April 21 a short glancing blow from the CME on April 18 was seen at the
Earth, together with the arrival of the high speed stream from another
(negative) coronal hole with speeds reaching 800 km/s and interplanetary
magnetic fields of 12 nT. The influence of this high speed stream continued
until the end of the week (and beyond) and it produced Kp = 6 and K =5.
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DAILY INDICES
DATE           RC   EISN  10CM   Ak   BKG    M   X
2017 Apr 17   ///    000   075   004   B1.1   0   0   
2017 Apr 18   ///    024   080   008   A9.7   0   0   
2017 Apr 19   ///    016   081   017   B1.3   0   0   
2017 Apr 20   033    029   081   025   B1.1   0   0   
2017 Apr 21   ///    041   082   024   B1.1   0   0   
2017 Apr 22   ///    031   084   039   B1.0   0   0   
2017 Apr 23   ///    042   083   040   A9.9   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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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.