:Issued: 2012 Jan 30 1536 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 578 from 2012 Jan 23
SOLAR ACTIVITY
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Solar activity was dominated by the flaring activity of NOAA AR 1402,
which produced a M8.7 flare on Jan. 23 (0359 UT peak time) accompanied
by a fast halo CME (1400 km/s as measured using COR2 A coronagraph)
and a proton event (10 and 50 MeV protons), which ended on Jan. 27.
The >10 MeV proton flux reached quite a high value of 6300 pfu
on Jan. 24 at about 1530 UT, shortly after the arrival of the shock linked
to the halo CME at Earth.
While close to the west limb, AR 1402 produced an X1.7 class flare on Jan. 27,
peaking at 1837 UT. It was linked again to a fast halo CME
(1900 km/s on COR2 A) and a new proton event from 10 to 100 MeV,
although the maximum of the 10 MeV flux was below 1000 pfu.
GEOMAGNETIC ACTIVITY
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Geomagnetic activity reached minor storm levels at planetary level on Jan. 24
due to the arrival of the shock, linked to the halo CME of Jan. 23 around 14:30 UT.
Unsettled to active periods were observed for nearly 24 hours. Apart from a brief
period of active conditions on Jan. 23, which was the tail of a previous minor storm,
the rest of the week was rather quiet.
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DAILY INDICES
DATE RC EISN 10CM Ak BKG M X
2012 Jan 23 149 073 144 008 B6.0 1 0
2012 Jan 24 128 051 136 022 B5.8 0 0
2012 Jan 25 /// 054 126 013 B4.9 0 0
2012 Jan 26 027 031 128 008 B7.3 0 0
2012 Jan 27 095 042 142 006 B5.2 0 1
2012 Jan 28 /// 029 115 008 B5.9 0 0
2012 Jan 29 /// 032 110 008 B2.7 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
23 0338 0359 0434 N28W21 M8.7 2B 5100 VII/2,IV/2 21 1402
27 1737 1837 1856 N27W71 X1.7 1F 810 II/3,IV/2 21 1402
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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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