SIDC Weekly Bulletin

:Issued: 2018 Sep 18 1357 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 924 from 2018 Sep 10
SOLAR ACTIVITY
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Solar activity was at very low levels. Only two inactive sunspot group were
observed: NOAA 2721 and NOAA 2722. No coronal mass ejections (CMEs) were
observed. The greater than 10 MeV proton flux was at nominal levels. A
trans-equatorial negative polarity coronal hole (CH) transited the central
meridian on 13-14 September.
GEOMAGNETIC ACTIVITY
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Solar wind conditions started the week under the influence of a positive
polarity coronal hole high speed stream (HSS). Solar wind speeds reached a
maximum of 620 km/s on 11-Sep-2018 and 650 km/s on 15-Sep-2018 before
starting a gradual decline. The total magnetic field strength has
fluctuated around 5 nT. The Bz component has fluctuated between -5 and +5
nT. 

Geomagnetic conditions ranged between Kp index 1-6 (NOAA) and local K index
0-5 (Dourbes) over the past week. The geomagnetic conditions reached storm
levels on a planetary level on Tuesday (11-Sep-2018), due to a jump in the
solar wind speed combined with a Southward orientation of the magnetic
field, caused by the HSS from the positive polarity coronal hole that
transited the central meridian on 8-Sep-2018.
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DAILY INDICES
DATE           RC   EISN  10CM   Ak   BKG    M   X
2018 Sep 10   ///    011   069   026   ////   0   0   
2018 Sep 11   016    015   069   034   ////   0   0   
2018 Sep 12   013    013   070   014   ////   0   0   
2018 Sep 13   ///    000   070   022   ////   0   0   
2018 Sep 14   000    000   069   018   ////   0   0   
2018 Sep 15   ///    000   069   009   ////   0   0   
2018 Sep 16   ///    000   069   007   ////   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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