:Issued: 2010 Dec 29 0751 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 521 from 2010 Dec 20
SOLAR ACTIVITY
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On Dec 15 however, a plasma structure high in the corona left the Sun.
It was clearly seen in STEREO COR2 images. LASCO on board SOHO
could also capture it but it looked very faint. The CME was not recognized
as a halo in LASCO.
Further, the Sun took a small Christmas holiday: no flares were measured.
GEOMAGNETIC ACTIVITY
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A shock leading the plasma cloud reached ACE on Dec 19. The cloud itself
passed on Dec 20. It was possibly the plasma structure that left the Sun
on Dec 15. The cloud can be recognized by the slowly varying magnetic
field components. Only unsettled conditions were measured on Dec 20.
Further this week, we had also a geomagnetic silence.
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DAILY INDICES
DATE RC EISN 10CM Ak BKG M X
2010 Dec 20 011 000 78 010 A3.7 0 0
2010 Dec 21 022 000 78 003 A3.5 0 0
2010 Dec 22 013 007 78 /// A3.3 0 0
2010 Dec 23 /// 008 80 /// A3.3 0 0
2010 Dec 24 025 008 79 003 A3.4 0 0
2010 Dec 25 /// 013 79 006 A3.5 0 0
2010 Dec 26 /// 016 81 004 A3.5 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
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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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