:Issued: 2010 Apr 06 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 483 from 2010 Mar 29
SOLAR ACTIVITY
--------------
Two sunspot groups were observed on the Sun during the last week: Catania numbers 54 and 56, NOAA ARs 1057 and 1059 respectively. The Catania sunspot group 54 did not produce any noticeable flaring activity.
Catania sunspot group 56 (NOAA AR 1059) situated at S15E40 was the source of the CME first detected by SOHO/LASCO C2 at 03:08 UT on March 30. The angular extent of the CME was around 110 degrees. It was accelerating to reach the speed of around 350 km/s in the LASCO C3 field of view. The CME was not associated with any reported flare. However, coronal dimmings and post-eruption loops were observed by SECCHI/EUVI onboard STEREO B starting from around 03:00 UT. The CME was the driver of the interplanetary shock wave detected on April 2 (see below).
A partial halo CME (angular width around 243 degrees) was detected on April 3. It was first seen at 10:33 UT (by LASCO) and at 09:54 UT (by SECCHI/COR2 onboard STEREO A). The CME was moving at a projected plane-of-the-sky speed of around 500 km/s (according to the LASCO data). The source region of the CME was the Catania sunspot group 56 (NOAA AR 1059) located at that moment around S25W05. The CME was accompanied by a filament disappearance, a post-eruption arcade, coronal dimmings, an EIT wave (as seen by SOHO/EIT) and a B7.4 flare peaking at 09:54 UT.
The arrival of the corresponding ICME (possibly an interplanetary flux rope) at the Earth was expected to occur late on April 5 - early on April 6 (the corresponding CME-driven shock wave actually arrived at 07:59 UT on April 5 according to the SOHO/CELIAS data). The flux rope orientation as inferred from the SOHO/EIT and SOHO/MDI data is ESW, although it may change during propagation. STEREO A and B data indicate that the bulk of the CME was propagating to the south of the ecliptic (according to the COR2 data). If the ICME will arrive, it may produce a major geomagnetic disturbance (peak Dst around -100 nT, peak K index around 6).
Another partial halo CME first observed by LASCO at 08:54 UT on March 29 was backsided according to the STEREO/SECCHI data.
GEOMAGNETIC ACTIVITY
--------------------
During the whole week, the Earth was situated inside a slow solar wind flow with average interplanetary magnetic field (IMF) magnitude. An interplanetary sector boundary was crossed by ACE on March 29 around noon, but no faster solar wind stream followed.
An interplanetary shock wave was detected by ACE and SOHO/CELIAS at 06:45 UT on April 2. The solar source of this shock is probably the CME detected on March 30 (see above). Due to the position of the erupting active region away from the solar central meridian and non-halo appearance of the CME, the corresponding ICME missed the Earth and only a shock was detected. The IMF magnitude reached 7 nT in the post-shock sheath. However, the IMF north-south component was fluctuating, so the K index reached only 3 (as reported by IZMIRAN and NOAA). Quiet geomagnetic conditions (with isolated intervals of unsettled conditions with K = 4) were thus reported during the whole week.
The shock arrival was not associated with any solar energetic particle event.
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DAILY INDICES
DATE RC EISN 10CM Ak BKG M X
2010 Mar 29 043 020 83 /// A3.6 0 0
2010 Mar 30 034 021 83 008 A3.9 0 0
2010 Mar 31 027 017 81 007 A3.1 0 0
2010 Apr 01 026 017 79 012 A2.8 0 0
2010 Apr 02 035 018 76 014 A2.9 0 0
2010 Apr 03 /// 018 77 014 A3.9 0 0
2010 Apr 04 /// 028 79 018 A4.2 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
#--------------------------------------------------------------------#
# 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 #
#--------------------------------------------------------------------#
:Product: documentation at http://www.sidc.be/products/bul
#--------------------------------------------------------------------#
# SIDC Weekly bulletin on Solar and Geomagnetic activity #
#--------------------------------------------------------------------#
WEEK 483 from 2010 Mar 29
SOLAR ACTIVITY
--------------
Two sunspot groups were observed on the Sun during the last week: Catania numbers 54 and 56, NOAA ARs 1057 and 1059 respectively. The Catania sunspot group 54 did not produce any noticeable flaring activity.
Catania sunspot group 56 (NOAA AR 1059) situated at S15E40 was the source of the CME first detected by SOHO/LASCO C2 at 03:08 UT on March 30. The angular extent of the CME was around 110 degrees. It was accelerating to reach the speed of around 350 km/s in the LASCO C3 field of view. The CME was not associated with any reported flare. However, coronal dimmings and post-eruption loops were observed by SECCHI/EUVI onboard STEREO B starting from around 03:00 UT. The CME was the driver of the interplanetary shock wave detected on April 2 (see below).
A partial halo CME (angular width around 243 degrees) was detected on April 3. It was first seen at 10:33 UT (by LASCO) and at 09:54 UT (by SECCHI/COR2 onboard STEREO A). The CME was moving at a projected plane-of-the-sky speed of around 500 km/s (according to the LASCO data). The source region of the CME was the Catania sunspot group 56 (NOAA AR 1059) located at that moment around S25W05. The CME was accompanied by a filament disappearance, a post-eruption arcade, coronal dimmings, an EIT wave (as seen by SOHO/EIT) and a B7.4 flare peaking at 09:54 UT.
The arrival of the corresponding ICME (possibly an interplanetary flux rope) at the Earth was expected to occur late on April 5 - early on April 6 (the corresponding CME-driven shock wave actually arrived at 07:59 UT on April 5 according to the SOHO/CELIAS data). The flux rope orientation as inferred from the SOHO/EIT and SOHO/MDI data is ESW, although it may change during propagation. STEREO A and B data indicate that the bulk of the CME was propagating to the south of the ecliptic (according to the COR2 data). If the ICME will arrive, it may produce a major geomagnetic disturbance (peak Dst around -100 nT, peak K index around 6).
Another partial halo CME first observed by LASCO at 08:54 UT on March 29 was backsided according to the STEREO/SECCHI data.
GEOMAGNETIC ACTIVITY
--------------------
During the whole week, the Earth was situated inside a slow solar wind flow with average interplanetary magnetic field (IMF) magnitude. An interplanetary sector boundary was crossed by ACE on March 29 around noon, but no faster solar wind stream followed.
An interplanetary shock wave was detected by ACE and SOHO/CELIAS at 06:45 UT on April 2. The solar source of this shock is probably the CME detected on March 30 (see above). Due to the position of the erupting active region away from the solar central meridian and non-halo appearance of the CME, the corresponding ICME missed the Earth and only a shock was detected. The IMF magnitude reached 7 nT in the post-shock sheath. However, the IMF north-south component was fluctuating, so the K index reached only 3 (as reported by IZMIRAN and NOAA). Quiet geomagnetic conditions (with isolated intervals of unsettled conditions with K = 4) were thus reported during the whole week.
The shock arrival was not associated with any solar energetic particle event.
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DAILY INDICES
DATE RC EISN 10CM Ak BKG M X
2010 Mar 29 043 020 83 /// A3.6 0 0
2010 Mar 30 034 021 83 008 A3.9 0 0
2010 Mar 31 027 017 81 007 A3.1 0 0
2010 Apr 01 026 017 79 012 A2.8 0 0
2010 Apr 02 035 018 76 014 A2.9 0 0
2010 Apr 03 /// 018 77 014 A3.9 0 0
2010 Apr 04 /// 028 79 018 A4.2 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
#--------------------------------------------------------------------#
# 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 #
#--------------------------------------------------------------------#
