lunedì 13 dicembre 2010

SIDC Weekly Bulletin

:Issued: 2010 Dec 13 1249 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 519 from 2010 Dec 06 

SOLAR ACTIVITY
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Solar activity was relatively low during the reporting period. The week started with an eruption of a large filament on monday December 6 around 15:35 UT, observed by PROBA2/SWAP and SDO/AIA. The associated CME was seen in STEREO/A COR2 images starting at 18:54 UT. The CME speed as measured by CACTUS was approximately 550 km/s.

On December 8th, the GOES X-ray curve indicated a long duration event, linked to NOAA AR 1133 (Catania 76). SDO/AIA 171 images showed a dimming at that location starting at 09h05. The B-flare was also accompanied by a CME observed through STEREO (by STEREO/A COR2 around 11h39). The CACTus CME detection based on the LASCO images estimated its speed around 450 km/s.

Another long duration B-flare was observed on December 12th. The associated CME is not expected to influence the Earth. Also the other CME observed on December 12th is not expected to hit Earth.

Flaring activity was low during the past week, with no C-flares to report. 


GEOMAGNETIC ACTIVITY
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The filament eruption on Monday December 6 was situated on the south-east side of the Sun, so the associated CME did not affect the Earth.

On the same day, there was a shock in the solar wind speed was observed by ACE due to a sector boundary change. Also the CME on December 8th did not reach the Earth. We are currently experiencing the effects of a fast wind stream originating from long stretched recurrent coronal hole, which was clearly observed during the whole week. The geomagnetic effects of the enhanced wind stream are limited however.

The solar wind speed was low during the week, on average around 350 km/s. The Dourbes K-index did not exceed a maximum of K=3.


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DAILY INDICES
DATE          RC  EISN  10CM  Ak  BKG    M  X
2010 Dec 06  ///    017  89  003  B1.0  0  0
2010 Dec 07  ///    017  87  006  A9.7  0  0
2010 Dec 08  ///    016  87  011  A8.6  0  0
2010 Dec 09  050    015  87  002  A8.8  0  0
2010 Dec 10  034    022  88  000  B1.0  0  0
2010 Dec 11  022    015  87  002  B1.2  0  0
2010 Dec 12  ///    015  89  005  B1.4  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                                          #
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