:Issued: 2010 Mar 23 1002 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 481 from 2010 Mar 15
SOLAR ACTIVITY
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Solar activity was low to very low over the full week, with
just a few B subflares. The GOES X-ray background flux was
mostly at A level. The largest sunspot group was Catania#52
(NOAA11054), which had spawned a halo CME on March 14. It
reached its largest development on March 15 (type D,
beta/gamma) but then decayed continuously until it disappeared
at the West limb on March 20, without producing any further
flaring activity.
GEOMAGNETIC ACTIVITY
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The geomagnetic field was quiet to unsettled over the entire
week, with just a brief active interval on March 17. This weak
disturbance was associated with a temporary enhancement of
the solar wind speed that peaked at 500km/s early on March 17.
This weak solar wind enhancement could be due either to a
recurrent fast solar wind stream or to the glacing blow of the
slow halo CME released at the Sun on March 14. The solar wind
speed then declined with a plateau at 400km/s on March 19-20,
causing temporary unsettled geomagnetic levels. On March 21,
all parameters finally returned to very quiet levels.
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DAILY INDICES
DATE RC EISN 10CM Ak BKG M X
2010 Mar 15 026 015 86 004 A5.2 0 0
2010 Mar 16 040 015 85 006 A3.8 0 0
2010 Mar 17 027 019 87 008 A4.3 0 0
2010 Mar 18 039 019 86 006 A4.8 0 0
2010 Mar 19 030 015 84 006 A3.8 0 0
2010 Mar 20 016 010 84 006 A6.1 0 0
2010 Mar 21 /// 017 85 002 A6.6 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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