:Issued: 2010 Apr 12 2053 UTC :Product: documentation at http://www.sidc.be/products/bul #--------------------------------------------------------------------# # SIDC Weekly bulletin on Solar and Geomagnetic activity # #--------------------------------------------------------------------# WEEK 484 from 2010 Apr 05 SOLAR ACTIVITY -------------- Solar activity was rather low during the week. A halo CME occurred on April 8, in conjunction with a B3.7 flare, which peaked at 0325 UT. The source region was NOAA AR 1060, at that time about 20 degrees East of the central meridian. A southward EUV coronal wave was observed. GEOMAGNETIC ACTIVITY -------------------- Geomagnetic activity was dominated from April 5 to 6 by a major geomagnetic storm (Kp=6), with brief periods of severe storm conditions (Kp=7) on April 5. Geomagnetic conditions were still at active levels (Kp=4) on April 7. The source of such disturbances is a halo CME, which occurred on April 3. A strong interplanetary shock was observed by the ACE spacecraft at 0756 UT on April 5. In addition, a fast solar wind stream linked to a coronal hole quickly followed the arrival of the shock and maintained at active levels an already disturbed situation. Conditions returned to quiet levels on April 8. A weak interplanetary shock was observed by the ACE spacecraft on April 11 at 1215 UT, in relation with the halo CME of April 8. A brief period of active conditions (K=4) was observed at Dourbes station on that day between 18 and 21 UT, while planetary conditions remained at quiet levels. --------------------------------------------------------------------------- DAILY INDICES DATE RC EISN 10CM Ak BKG M X 2010 Apr 05 /// 026 79 050 A4.1 0 0 2010 Apr 06 /// 019 78 039 A3.1 0 0 2010 Apr 07 /// 017 76 024 A3.2 0 0 2010 Apr 08 037 021 76 015 A4.1 0 0 2010 Apr 09 012 007 76 008 A3.5 0 0 2010 Apr 10 011 007 75 003 A4.4 0 0 2010 Apr 11 /// 000 75 018 A2.7 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) --------------------------------------------------------------------------- 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 # # # # For more information, see http://www.sidc.be. Please do not reply # # directly to this message, but send comments and suggestions to # # 'sidctech@oma.be'. If you are unable to use that address, use # # 'rvdlinden@spd.aas.org' instead. # # To unsubscribe, visit http://sidc.be/registration/unsub.php # #--------------------------------------------------------------------#