SIDC Weekly Bulletin

:Issued: 2012 May 17 0919 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 593 from 2012 May 07  

SOLAR ACTIVITY
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Several M-flares were produced from Monday May 7 till Thursday May 10. NOAA AR
1471 was active in the beginning 
of  the period (M1.9 flare on May 7) but most flaring and the largest flare of
the period (M5.7 on May 10) was 
produced by NOAA AR 1476.  After that, flaring activity decreased although NOAA
AR 1476 retained a 
beta-gamma-delta configuration till the end of the period.

The ACE low energy proton fluctuated since May 11 suggesting that the Earth
environment was magnetically connected 
to NOAA AR 1476 in the second half of the period. Nevertheless, the NOAA GOES
proton event threshold was not 
reached during the period.


GEOMAGNETIC ACTIVITY
---------------------

Enhanced geomagnetic conditions were observed on May 9 and May 10. KDourbes, as
well as NOAA's planetary 
K-index registered K=4 values. This enhanced activity was a consequence of a
coronal hole passing the solar central 
meridian. The solar wind speed, as recorded by the ACE spacecraft at L1,
gradually rose from 300km/s to nearly 
700 km/s with intermittent episodes in which the Bz component of the
interplanetary magnetic field turned southwards.
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DAILY INDICES
DATE           RC   EISN  10CM   Ak   BKG    M   X
2012 May 07   150    055   122   004   B5.9   1   0
2012 May 08   105    059   123   012   B3.5   1   0
2012 May 09   113    061   127   031   B4.1   3   0
2012 May 10   126    066   131   012   B6.5   2   0
2012 May 11   140    074   136   012   B6.1   0   0
2012 May 12   ///    066   130   012   B4.9   0   0
2012 May 13   ///    068   131   014   B4.2   0   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)
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NOTICEABLE EVENTS
DAY BEGIN MAX  END  LOC    XRAY OP TENCM TYPE                       Cat NOAA
NOTE 
07  1403  1431 1452 S19W46 M1.9 1N 230   IV/1                           1471  
08  1302  1308 1312 N13E44 M1.4 1F 69                                   1476 
09  1221  1232 1236 N13E31 M4.7 1N 110                                  1476 
09  1402  1408 1414 N06E22 M1.8 1B 68    III/2                          1476 
09  2101  2105 2109        M4.1    240                                  1476 
10  0411  0418 0423 N13E22 M5.7 2B 690   III/2                          1476 
10  2020  2026 2030 N12E12 M1.7    100                              25  1476 

 
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