Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 23 - 29.04.2012, Forecast on 30.04 - 06.05.2012, ëüòòéîçôïîï÷óëéå ïâïòïôù 2122, 2123 (31,93.03, 28,19.04.2012) SUNSPOT ACTIVITY OF THE PAST PERIOD GRADUALLY CHANGEDED FROM HIGH TO AVERAGE LEVELS. ESTIMATED, RATING, WEEKLY THE AVERAGE OF SUNSPOT NUM- BER IN THE INTERNATIONAL SYSTEM FOR THE PERIOD WAS MADE W=078+23/-19. ON THE VISIBLE DISK OF THE SUN CONSTANTLY THERE WERE 5 - 8 QUIET SUN- SPOT GROUPS THREE OF WHICH WERE THE AVERAGE SIZE, BUT LATER 26.04 ALL SUNSPOT GROUPS WERE SMALL. NEXT WEEK THE LEVEL OF SUNSPOT ACTIVITY IS EXPECTED TO BE AVERAGE. THE CALCULATED MOST LIKELY WEEKLY AVERAGE VALUE OF SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM FOR THE NEXT WEEK W=060+10/-20. FLARE ACTIVITY AT 27.04 WAS ON THE MIDDLE LEVEL AND THE LOW IN OTHER DAYS. BY DATA OF SOHO CORONOGRAPHS FOR THE PERIOD IT WAS OBSERVED 34 CORONAL MASS EJECTIONS AMONG WHICH THE ONE WAS THE TYPE "HALO" (BACK SIDE EVENT AND 4 WERE "PARTIAL HALO II" TYPE (16, 18, 19.04). ------------------------------------------------------------------- FLARES to tm te c/p local. Class E(1-8A) AR RII/IV CME X / opt. J/m-2 27.04 0715 0724 0846 N11W30L039 M1.0/1N 5.8E-3 11466 DSF to te c/p local. l in deg. Fl AR CME 27.04 >1236 <1045 S35W14L018 16 28.04 1045 S32W33L020 16 CME/1224 28.04 >1017 <0430 S49W10L357 21 28.04 1800 2000 N06E36L311 6 11467 CME/1936 c/p local. - central part localization -------------------------------------------------------------------- NEXT WEEK FLARE ACTIVITY IS EXPECTED ON LOW AND AVERAGE LEVELS. ON THE VISIBLE SOLAR DISK DURING THE LAST WEEK THE FOLLOWING CORONAL HOLES WERE OBSERVED: --------------------------------------------------------------------- sign N end Å end S end W end EE R Observatories CH - N50L111 N43L093 N40L113 N45L116 23.04 3 KP, SDO, SOHO... CH - N27L062 N25L060 N18L072 N23L075 25.04 4 KP, SDO, SOHO... CH + N38L001 N35L358 N16L013 N21L015 30.04 1 KP, SDO, SOHO... R - solar rotations; KP - KITT PEAK solar observatory; EE-date of possible geomag. disturbation in the Earth's environment. --------------------------------------------------------------------- AFTER 24.04/04 UT THE EARTH WAS IN "-" SECTOR OF THE INTERPLANETARY MAGNETIC FIELD. THE FOLLOWING SECTOR BOUNDERY - /+ THE EARTH SHOULD PASS 02.05. APRIL 23 24 25 26 27 28 29 APRIL Wus 158 169 137 117 099 118 114 F10.7 142 134 127 119 118 121 116 èbcg B5.5 ÷5.1 B4.7 ÷4.1 ÷5.8 ÷5.2 ÷3.7 GOES Sp 1580 1340 920 540 480 570 660 Nnew 3 2 1 IMF - - - - -/+ + + ACE Å>2 9.8å+5 2.6å+6 2.1E+8 1.4å+8 3.2å+8 3.7å+8 2.60å+8 GOES Nm% THULE Ap 24 35 19 16 8 5 4 áÒ Dst ëIOTO Amsc 21 35 20 14 9 11 6 IZMIRAN --------------------------------------------------------------- THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSTATIONARY ORBIT VERY HIGH LEVEL OF FLUX WAS OBSERVED FROM 25.04/0220 UT on APRIL 25-29 AS A RESULT OF PASS TO EARTH OF THE SOLAR WIND HIGH-SPEED STREAM FROM CORONAL HOLE ON THE SOLAR NORTHERN HEMISPHERE. THE GREATER THAN 2 MeV ELECTRON FLUX AT HIGH LEVEL AFTER MAY, 1 IS NOT EXPECTED. LAST WEEK BEGAN WITH THE MODERATE MAGNETIC STORM ON APRIL 23-24 (G2, Ams=6, dur.=21 h.) ACCORDING TO IZMIRAN DATA AND (G2, Ams = 50, dur.=18 h.) ACCORDING TO THE SW CENTER IN BOULDER WHEN TO EARTH CAME THE DISTURBANCE FROM SOLAR FILAMENT EJECTA 19.04, ACCOM- PANIED CME OF TYPE "PARTIAL GALO II". OVER 6 HOURS TO EARTH ONE MO- RE DISTURBANCE FROM THE UNKNOWN SOURCE CAME, RESULT WHICH BECAME MINOR MAGNETIC STORM ON APRIL 24-25 (G1, Ams=25, dur.=15 h.) ACCOR- DING TO THE SW CENTER IN BOULDER. ACCORDING TO IZMIRAN DATA THIS MAGNETIC DISTURBANCE REPRESENTED THE SUBSTORM OF G1 INTENSITY AND 7 h. DURATION. OVER NEXT 6 HOURS EARTH WAS BEGINING CROSSED THE HIGH-SPEED STREAM OF THE SOLAR WIND FROM RECURRENT CORONAL HOLE OF THE SOLAR NORTHERN HEMISPHERE. THE MINOR MAGNETIC STORM WAS REGIS- TERED ON APRIL 25 - 26 (G1, Ams= 35, dur.=15 h.) ACCORDING TO THE BOULDER SW CENTER AND (G0, Ams=24, dur.=15 h.) BY IZMIRAN DATA. IN OTHER DAYS THE GEOMAGNETIC CONDITIONS WAS UNSETTLED AND QUIET. NEXT WEEK ON MAY 1-2 PROBABLY GROWTH OF GEOMAGNETIC ACTIVITY AFTER ARRIVAL TO EARTH THE DISTURBANCE FROM SOLAR FILAMENTS EJECTA 27- 28.04. PROBABILITY OF THE MAGNETIC STORM ABOUT 60 %. IN OTHER DAYS THE GEOMAGNETIC CONDITION IS EXPECTED UNSETTLED AND QUIET. HIGHLIGHT AND FORECAST COMPOSED FROM DATA OF NOAA SWPC http://www.sec.noaa.gov, OF THE SOLAR INFLUENCES DATA ANALYSIS CENTER - SIDC, BELGIUM http://sidc.oma.be/index.php3, OF THE IZMIRAN, RUSSIA http://www.izmiran.ru