Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 20 - 26.04.2015, Forecast on 27.04 - 04.05.2015, Carrington Rotationù 2162, 2163 (27,93.03; 24,21.04.2015) SUNSPOT-FORMING ACTIVITY OF THE SUN WAS AT THE SURE AVERAGE LEVEL, SMOOTHLY DECREASING BY THE END OF THE PERIOD, BUT 21 APRIL ROSE TO HIGH LEVEL. ESTIMATED, WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM WAS MADE W=077+15/-6. ON THE VI- SIBLE SOLAR DISK CONSTANTLY OBSERVED 4-9 SMALL SUNSPOT GROUPS. SUNSPOT-FORMING ACTIVITY IS EXPECTED TO BE AT AVERAGE TO LOW LE- VELS. ESTIMATED, MOST LIKELY WEEKLY AVERAGE VALUE OF RELATIVE SUN- SPOT NUMBER IN THE INTERNATIONAL SYSTEM FOR THE NEXT WEEK IS EX- PECTED W = 040+20/-10. FLARE ACTIVITY WAS AT THE AVERAGE LEVEL ON APRIL 21-23 AND ON LOW IN OTHER DAYS. GROWTH OF FLARE ACTIVITY IS CONNECTED WITH ACTIVIZA- TION OF VERY SMALL SUNSPOT GROUP (AR12322) AT THE WESTERN LIMB (W80) OF THE SUN. IN THIS ACTIVE REGION IN 50 HOURS 8 FLARES OF THE AVERA- GE X-RAY CLASS WERE OCCURRENCE. VISIBLE SIGNIFICANT SIGNS OF EMER- GANCE OF THE NEW MAGNETIC FLUX ON SUCH LONGITUDES CAN'T BE REVEALED AND THEREFORE THE FORECAST OF THIS FLARE ENERGY RELEASE WAS STILL IMPOSSIBLE. SEVEN SOLAR FILAMENT EJECTIONS OCCURRENCES THROUGH THE PERIOD. BY DATA OF CORONOGRAPHS SOHO AND STEREO WERE OBSERVED > 34 CME FROM WHICH ONE WAS "HALO" TYPE, ONE - "PARTIAL HALO III" TYPE AND FOUR - "PARTIAL HALO II" TYPE. ------------------------------------------------------------------- FLARES to tm te c/p local.Class E(1-8A) AR RII/IV CME X-ray/Ïp J/m-2 21.04 0708 0721 0731 N09W80L116 M1.0/SF 6.4E-03 12322 21.04 1017 1040 >1059 N16E80L116 M2.2/ 3.7E-02 12322? 21.04 1141 1157 1226 N10W84l116 M2.2/SF 1.1E-02 12322 21.04 1655 1700 >1709 N13W84L116 M2.1/SF 1.2E-02 12322 21.04 2139 2145 >2155 N10W80L116 M1.8/ 1.1E-02 12322 21.04 2158 2201 >2204 N09W80L116 M1.2 2.8E-03 12322 22.04 0830 0844 >0858 S09E05L116 M1.1/SF 1.2E-02 12322 23.04 0918 1007 >1110 N07W80L121 M1.1/ 5.7E-02 12322 DSF to te c/p local. l in deg. Fl AR CME 19.04 >1413 <0458 S39W56L000 6 20.04 >0804 <0048 S32E44L000 12 21.04 0136 0406 N10W13L043 6 12325 22.04 >0104 <1255 N11E02L015 7 24.04 0510 0555 N22E51L296 8 12333 25.04 >0006 <1307 S26E23L314 14 25.04 0359 0557 S20W32L006 12 12331 -------------------------------------------------------------------- NEXT WEEK FLARE ACTIVITY IS EXPECTED AT THE LOW LEVEL. ON THE VISIBLE SOLAR DISK THE FOLLOWING CORONAL HOLES WERE OBSERVED: -------------------------------------------------------------------- sign N end Å end S end W end EE R G Observatories CH - S12L074 S15L062 S25L078 S20L084 20.04 2 G1 SDO, SOHO... óî + S01L310 S22L295 S25L297 S18L315 30.04 3 G0 SDO, SOHO... óî + N60L277 N50L247 N28L279 N35L287 1-2.05 1 SDO, SOHO... R - solar rotations; KP - KIT PEAK solar observatory; EE-date of possible geomag. disturbance in the Earth's environment. G - geoeffectivity in last solar rotation; A-active geomagnetic condition. --------------------------------------------------------------------- FROM 20.04/14 UT THE EARTH IS IN "+" SECTOR OF THE INTERPLANETARY MAG- NETIC FIELD. THE FOLLOWING SECTOR BOUNDARY +/- THE EARTH HAS TO PASS 7.05. APRIL 20 21 22 23 24 25 26 APRIL Wus 125 153 134 110 079 077 055 F10.7 150 154 150 141 135 126 119 èbcg B5.6 B9.0 B9.0 B7.1 B7.1 B5.1 B3.8 GOES Sp 750 670 630 630 480 550 530 msh N 1 2 1 IMF -/+ + + + + + + áóå Å>2 7.0å+7 3.3å+7 2.8å+7 4.2å+7 5.1E+7 7.6E+7 6.9å+7 GOES Ie>2 pfu GOES Ap 9 23 11 7 5 3 3 nT Dst -26 -29 -22 -11 nT ëéïôï Amsc 15 14 11 9 10 7 8 nT IZMIRAN -------------------------------------------------------------------- Å>2 - Daily Electron Fluency e/(cm2-ster-day) with E>2 MeV. Ie>2 - the maximum intensity of electron flux in geostationary orbits in days according to GOES 15 in (electrons/cm2-s-sr) for events > 1000 pfu. THE GREATER THEN 2 MeV ELECTRON FLUX AT GEOSTATIONARY ORBIT BEGAN 16. 04/1330UT AND WAS OBSERVED 20 - 21.04. THE SECOND GROWTH BEGAN 24.04/1555 UT AND WAS OBSERVED 24-26.04 THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSTATIONARY ORBIT OF VERY HIGH LEVEL IS EXPECTED 27 - 28.04. GEOMAGNETIC CONDITIONS GENERALLY WERE UNSETTLED. ONLY 21.04 ACCORDING TO THE CENTRE IN BOULDER DATA THE MINOR MAGNETIC STORM WAS REGISTE- RED (G0, Ams=25, dur.=18 h.), AND according to IZMIRAN IT was 6 HOUR SUBSTORM of G0 INTENSITY. RESPONSIBLE FOR THIS GEOMAGNETIC DISTURBAN- CE WAS THE SOLAR WIND HIGH-SPEED STREAM OF SOLAR SOUTHERN HEMISPHERE CORONAL HOLE. NEXT WEEK THE GROWTH OF GEOMAGNETIC DISTURBANCE IS POSSIBLE 30.04 WHEN THE EARTH PASSES THE HIGH-SPEED STREAM OF THE SOLAR WIND FROM SOUTHERN CORONAL HOLE. IN OTHER DAYS THE GEOMAGNETIC CONDITIONS IS EX- PECTED UNSETTLED AND QUIET. HIGHLIGHT AND FORECAST COMPOSED FROM DATA OF NOAA SWPC, BOULDER, USA http://www.swpc.noaa.gov, OF THE SOLAR INFLUENCES DATA ANALYSIS CENTRE - SIDC, BRUSSEL, BELGIUM http://sidc.oma.be/index.php3, OF THE IZMIRAN, MOSCOW, TROITSK, RUSSIA http://www.izmiran.ru