:Issued: 2011 Apr 20 1329 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 537 from 2011 Apr 11
SOLAR ACTIVITY
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Six ARs were active in producing mostly C-class flares during the week (NOAA
ARs 1185, 1186, 1189, 1190, 1191 and 1193). There was an M1.3 flare from AR 1190,
at 17:12 UT on April 15. CMEs occurred every day with only one directed partially
towards the Earth, consequence of a filament eruption in the southeast of the
Sun on April 14 around 23:00 UT.
GEOMAGNETIC ACTIVITY
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A fast solar wind stream arrived to the Earth on April 12 and produced a
minor geomagnetic storm with two three-hour periods of Kp=5.
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DAILY INDICES
DATE RC EISN 10CM Ak BKG M X
2011 Apr 11 075 043 106 012 B3.0 0 0
2011 Apr 12 092 055 110 023 B3.9 0 0
2011 Apr 13 132 070 118 011 B5.5 0 0
2011 Apr 14 154 082 119 005 B5.8 0 0
2011 Apr 15 /// 082 129 006 B6.2 1 0
2011 Apr 16 /// 064 119 004 B5.5 0 0
2011 Apr 17 /// 049 114 003 B4.1 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
15 1702 1712 1728 N14W19 M1.3 1F 64 1190
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# Solar Influences Data analysis Center - RWC Belgium #
# Royal Observatory of Belgium #
# Fax : 32 (0) 2 373 0 224 #
# Tel.: 32 (0) 2 373 0 491 #
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