Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 09 - 15.04.2012, Forecast on 16 - 23.04.2012, Carrington Rotations 2122 (04,28.04.2012) SUNSPOT ACTIVITY OF THE PAST PERIOD GRADUALLY INCREASED FROM LOW LEVEL AT THE BEGINNING OF THE PERIOD TO THE AVERAGE BY THE END. ESTIMATED, RATING, WEEKLY AVERAGE OF SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM FOR THE PERIOD WAS MADE W=027+19/-13. ON THE VISIBLE SOLAR DISK CONS- TANTLY PRESENT FROM 2 TO 5 QUTE, SMALL SUNSPOT GROUPS. NEXT WEEK THE SUNSPOT ACTIVITY IS EXPECTED TO BE LOW. THE CALCULA- TED MOST LIKELY WEEKLY AVERAGE VALUE OF SUNSPOT NUMBER IN THE INTER- NATIONAL SYSTEM FOR THE NEXT WEEK W=040+20/-10. FLARE ACTIVITY AT 9 AND 15.04 WAS ON THE LOW LEVELS AND OTHER DAYS AT VERY LOW. BY DATA OF SOHO CORONOGRAPHS FOR THE PERIOD IT WAS OBSERVED 27 CORONAL MASS EJECTIONS AMONG WHICH 4 WERE TYPE "PARTIAL HALO II" (9, 14, 15.04). ------------------------------------------------------------------- FLARES to tm te c/p local. Class E(1-8A) AR RII/IV CME X/opt. J/m-2 DSF to te c/p local. l in deg. Fl AR CME 07.04 1825 1900 N17W36L304 7 C2.4/ 11451 CME/2125 UT c/p local. - central part localization -------------------------------------------------------------------- NEXT WEEK FLARE ACTIVITY IS EXPECTED ON LOW AND VERY LOW 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 - N22L229 N10L223 S08L234 N08L242 12.04 3 KP, SDO, SOHO... CH - S17L236 S30L231 S38L234 S30L248 12.04 4 KP, SDO, SOHO... R - solar rotations; KP - KITT PEAK solar observatory; EE-date of possible geomag. disturbation in the Earth's environment. --------------------------------------------------------------------- AFTER 10.04/21 UT THE EARTH WAS IN "-" SECTOR OF THE INTERPLANETARY MAGNETIC FIELD. THE FOLLOWING SECTOR BOUNDERY - /+ THE EARTH SHOULD PASS 19.04. APRIL 09 10 11 12 13 14 15 APRIL Wus 024 024 028 050 050 065 077 F10.7 095 093 093 095 098 098 102 èbcg B1.1 ÷1.1 B1.1 ÷1.2 ÷1.5 ÷1.5 ÷2.4 GOES Sp 130 015 050 100 150 220 270 Nnew 1 1 1 1 IMF + + /- - - - - - ACE Å>2 1.6å+7 5.0å+6 6.8E+6 1.5å+6 8.4å+6 4.8å+9 6.0å+9 GOES Nm% THULE Ap 3 7 5 13 23 9 5 áÒ Dst -15 -21 -8 -46 -53 -31 -22 ëIOTO Amsc 11 12 9 18 21 13 12 IZMIRAN --------------------------------------------------------------- THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT VERY HIGH LEVEL OF FLUX WAS OBSERVED 14-15.04. THE GREATER THAN 2 MeV ELECTRON FLUX AT HIGH LEVEL IS EXPECTED 16 -19.04. TO THE LAST QUARTER OF DAYS ON APRIL 12 THE GEOMAGNETIC CONDITIONS REMAINED UNSETTLED AND QUIET WHEN THE EARTH BEGAN PASS THE HIGH- SPEED STREAM OF THE SOLAR WIND FROM VERY LARGE TRANSEQUATORIAL CORONAL HOLE. ACCORDING TO IZMIRAN DATA MINOR MAGNETIC STORM (G1, Ams=30, dur.= 18 h.) AND ACCORDING TO SERVICE SWPC (BOULDER, Ap) - (G1, Ams=34, dur. = 18 h.). ON APRIL 14 AND 15 THE GEOMAGNETIC CON- DITIONS WAS UNSETTLED AND QUIET. NEXT WEEK THE GEOMAGNETIC CONDITIONS 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