:Issued: 2005 Jan 25 1230 UTC :Product: documentation at http://www.sidc.be/products/bul #--------------------------------------------------------------------# # SIDC Weekly bulletin on Solar and Geomagnetic activity # #--------------------------------------------------------------------# FORECASTER: ronald DOY: 25 Time: 1339 BODY: Solar Influences Data Center (SIDC) / RWC Belgium Royal Observatory of Belgium E-mail: Ronald.Vanderlinden@oma.be http://sidc.oma.be SIDC WEEKLY BULLETIN -------------------- WEEK 212 from 2005 Jan 17 SOLAR ACTIVITY -------------- The whole week was dominated by one single sunspot group: Catania nr 05, NOAA 0720. We will give an overview of its life and most remarkable achievements, not only restricted to this week. Nr 05, 0720 came in view from Jan 10 onwards, grew very fast in size and complexity, although it was until Jan 13 responsible for only a few B-flares. The group was so big, that it was visible on the solar disk with the naked eye! From Jan 15 onwards, the group marked an M and X-flaring period with a wide impact on us and human technology. We make notice of these events in order of time. Saturday, Jan 15, the group served an X1.2 flare peaking at 00:43UT as a starter. From that moment onwards, flares/CMEs/proton events,… were the ingredients of our main course, on a daily basis: 1) An energetic long duration M8.4-flare, peaked at 04:31 UT, Jan 15. A full halo CME with median/maximum speed of 889/1745 km/s was detected by CACTus. A first glimpse of the CME in LASCO/C2 was seen at 06:06 UT. A strong 10cm flux radiation was measured (3000 sfu, solar flux units). 2) Another long duration flare, in the X-band: X2.6, peaked at 23:02 UT, Jan 15. A full halo CME with median/maximum speed of 1488/1960 km/s was detected by CACTus at 23:06 UT in LASCO/C2. An even stronger output in the 10cm wavelength was measured: 6400 sfu. 3) An X3.8 flare was seen, with a bulb in the X-radiation output curve before the peak time at 09:52 UT, Jan 17. An associated full halo CME at 1567/1974 km/s was detected at 09:30 UT, this is before the peak in X-radiation. 4) A triple M6.7/X1.3/M2.7 flare peaked at 08:22 UT, Jan 19 with an associated full halo CME coming out of the occulting disk of LASCO/C2 at 08:29 with a median/maximum speed of 1516/1977 km/s. The 10cm flux measured at a time linked with the M6.7 flare had the value of 5000 sfu. 5) The last flare was the most energetic one: it peaked at the value of X7.1 at 07:01 UT, Jan 20. A full halo CME was detected at 06:54 UT with median/maximum speed of 994/1689 km/s. The 10cm flux output was 8400 sfu. Together with the flares and associated CMEs, several proton events occurred. We describe the behavior of the proton fluxes measured by GOES11 linked with the corresponding events listed above. 1) The >10, >50, >100MeV curves increased, but did not pass the threshold. 2) Jan 16, just after midnight, all three curves increased, >10MeV passed the threshold a little later, the >50 MeV passed the threshold slightly around 15:00UT. The form of the curves reveal a CME-shockfront driven increase. 3) A more steep increase of all three curves above the threshold was measured on Jan 17 and was related to the X3.8 flare and associated CME. On Jan 18, only the >10 and >50 MeV curves were still above the threshold. 4) All three curves were influenced only slightly because of the triple flare: the decrease which was set from late Jan 17 onwards, was less pronounced because of this triple flare. 5) The X7.0 flare peaking at 07:00UT caused an EXTREME proton event: from 06:55 UT, the >10, >50 and >100 MeV-curves increased instantaneous. The >100 MeV curve went up to almost the same extremely high level as the >10 MeV and >50 MeV curves. This instantaneous increase and fast decrease of all three curves is clearly flare-driven: the flare itself has enough energy to accelerate all particles, including the high energy protons. Once the flare is finished, the flare-driven acceleration stops and the curves decrease rapid. Although, the >100 MeV showed a stronger decrease, contrary to the other two curves. This behaviour of the >10 and >50 MeV curves (i.e. slower decrease compared to the >100 MeV curve), points in the direction of a related CME: the shock front accelerates further the lower energy particles. The passing of this shock-front next to the satellite on Jan 21, 16:48 UT is visible as the curves of the proton fluxes show a sudden drop. Finally, not to be forgotten during these times of extreme space weather caused by a single group: a northern hemispheric coronal hole was situated at the central meridian on Jan 20. GEOMAGNETIC ACTIVITY -------------------- >From Jan 16, up till Jan 21, several ICMEs (Interplanetary CME) and shock-fronts passed ACE, situated at the L1 point. As a consequence, we had some severe geomagnetic storms. We will list the events as they are seen in ACE. Unfortunately, the ACE/SWEPAM instrument was contaminated for two periods because of the proton events. From Jan 17, around 13:00UT up till Jan 19, 22:00 UT and from Jan 20, 07:00 UT until Jan 21, around 04:00 UT, no solar wind speed data was available. 1) On Jan 16, ACE data showed a changing in several physical quantities (around 09:30UT): higher density, decreasing temperature, high solar wind speed, increased total interplanetary magnetic field. These are signatures of an ICME passing ACE. The consequence was a K_p of 5-4 on Jan 17, in the time intervals 00/03-03/06 UT. 2) A clear shock can be seen in ACE-data at 7:00UT, Jan 17. The solar wind speed jumped from slightly beneath 600 up to 650 km/s. Around 10:30 UT the speed rose more smoothly to 800 km/s. The total Interplanetary magnetic field (B_t) went up to 40nT, while B_z reached the level up till -20nT. This was the onset for a severe geomagnetic storm as K_p went up to 7 on Jan 17 (9/12-12/15-15/18 UT). 3) In the night between Jan 17 and Jan 18, around 23:00 UT, 02:30 UT, 05:30 UT, several drastic changes in B_t and B_z were visible. (note: SWEPAM was contaminated from around 13:00 UT, Jan 17 until 22:00 UT, Jan 18. Beginning of Jan 19, the solar wind speed was 1000 km/s). The result was two days (Jan 18 and Jan 19) of severe geomagnetic disturbances. 4) Early Jan 20, ACE showed some evidence (in solar wind speed and total magnetic field) for another ICME passing through. From 07:00 UT, the SWEPAM instrument was for a second time contaminated, as a consequence of the X7.1 flare. This ICME caused only active conditions in the second half of Jan 20. 5) A shock in the L1 point was identified at 16:48UT, Jan 21. The solar wind speed made a sudden jump from 600 up to 1000 km/s. The B_z went up to more than -20nT, leading to a sudden severe geomagnetic storm with K_p equal 8 (K_p on Jan 21-Jan 22:31322886-563). These ICMEs and shocks can possibly correspond to the full halo CMEs of the first part of the bulletin (corresponding numbers). Late Jan 22, continuing Jan 23, we experienced active conditions as consequence of the coronal hole mentioned at the end of the first part of this bulletin. The typical wind stream curve coming from a coronal hole is partially visible from Jan 22. The CME arrivals and corresponding increased solar wind speed over plotted the typical coronal hole speed curve. From Jan 24, the solar wind started to decrease gradually. --------------------------------------------------------------------------- DAILY INDICES DATE RC 10CM Ak BKG M X 2005 Jan 17 112 138 /// C1.5 1 1 2005 Jan 18 092 124 /// B7.1 2 0 2005 Jan 19 /// 133 /// B6.8 3 1 2005 Jan 20 065 123 /// B8.7 0 1 2005 Jan 21 068 114 /// B6.2 2 0 2005 Jan 22 044 102 /// B3.0 0 0 2005 Jan 23 /// 96 /// B1.5 1 0 # RC : Sunspot index from Catania Observatory (Italy) # 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 17 0310 0321 0332 N12W19 M2.6 05 0720 SXI-derived loc 17 0659 0952 1007 N15W26 X3.8 05 0720 SXI-derived loc, full halo CME 18 1123 1132 1159 N13W38 M1.6 05 0720 SXI-derived loc 18 1538 1551 1559 N14W40 M4.6 2N 100 05 0720 19 0658 0731 0755 N19W47 M6.7 2N 5000 CTM/1,III/3 05 0720 1st part of triple flare 19 0803 0822 0840 N15W50 X1.3 II/2,IV/2 05 0720 full halo CME (08:22 in LASCO), 2th part of triple flare,SXI-derived loc 19 1019 1024 1029 N18W47 M2.7 1N III/3 05 0720 3th part of a triple flare 19 1532 1540 1548 N13W50 M1.6 2F 05 0720 20 0636 0701 0726 N12W58 X7.1 2B 8400 IV/2,II/2 05 0720 full halo CME 21 1010 1016 1019 N17W73 M1.7 51 III/1 05 0720 SXI-derived loc 21 1347 1355 1410 S07W89 M1.2 04 0718 SXI-derived loc 23 0128 0151 0201 N15W88 M1.0 05 0720 SXI-derived loc #--------------------------------------------------------------------# # 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. 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