Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 17 - 23.04.2017, Forecast on 24 - 30.04.2017, Carrington Rotations 2189, 2190 (02,37.04; 29,63.04.2017) Earth above the ecliptic (-5.4, -5,0) deg. (S30-N28 is geoeffectiveness zone) SUNSPOT-FORMING ACTIVITY WAS ON A VERY LOW LEVEL TO 19.04 (17.04 day was spotless-30th in this year), 20 AND 22- AT LOW, 21, 23- AT MIDDLE. THE ESTIMATED, MOST LIKELY WEEKLY AVERAGE VALUE OF THE RELATIVE SUN- SPOT NUMBER IN THE INTERNATIONAL SYSTEM (old) FOR THE THE PERIOD IS W=14+12/-14 (Wn=22+19/-22). ON THE VISIBLE DISC OF THE SUN 0- 3 SMALL QUITE SUNSPOT GROUP. NEXT WEEK SUNSPOT-FORMING ACTIVITY IS EXPECTED AT THE LOW AND VERY LOW LEVELS. THE ESTIMATED, MOST LIKELY WEEKLY AVERAGE VALUE OF THE RE- LATIVE SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM (old) FOR THE NEXT WEEK IS W=30+20/-20. FLARE ACTIVITY WAS AT THE LOW LEVEL AT 17-18.04 AND VERY LOW IN OTHER DAYS. 12 SOLAR FILAMENT EJECTION OCCURRENCES THROUGH THE PERIOD. ACCOR- DING TO THE SOHO AND STEREO CORONOGRAPHS DATA > 18 CMEs, ONE OF WHICH WAS TYPE II (angular with 144 deg.) HAVE BEEN OBSERVED. ---------------------------------------------------------------------- FLARES to tm te local. Class E(1-8A) AR RII/IV CME X-ray/Ïp J/m-2 DSF to te ËÏÏÒÄÉÎÁÔÙ l × ÇÒÁÄ. Fl Aï CME/to 19.04 >0114 >1300 S59E39L101 16 óíå/1820 20.04 >0101 >1315 N43E25L101 8 20.04 >0943 >2313 N27E34L092 11 20.04 >1644 >0604 N23E23L103 6 20.04 2026 2123 N19E18L108 12 20.04 <2200 N14E77L072 ? C5.5 12651 CME/2200 21.04 >0108 >1255 S46W16L128 5 21.04 >0850 >2317 S57E18L194 7 21.04 >1413 >0702 N19E35L064 11 22.10 >1657 >0511 N24E26L073 6 23.10 0416 0520 0536 N12E39L046 10 12652 CME/0600 23.04 1658 1734 N32E00L085 10 ---------------------------------------------------------------------- NEXT WEEK FLARE ACTIVITY IS EXPECTED AT A LOW AND VERY LOW LEVELS. ON THE VISIBLE SOLAR DISK THE FOLLOWING CORONAL HOLES WERE OBSERVED: --------------------------------------------------------------------- sign N end E end S end W end Sch EE R G Space Obser. CH + S15L225 S22L223 S30L221 S20L225 17.04 7 G1 SDO, SOHO.. CH + N12L185 S20L175 S23L173 S18L190 12200 19.04 7 G1 SDO, SOHO.. CH - N20L111 S10L093 S15L107 S05L124 66200 24.04 7 G2 SDO, SOHO.. CH - S16L102 S20L077 S38L092 S20L107 66200 25.04 7 G1 SDO, SOHO.. CH - S30L067 S38L065 S60L053 S35L082 25000 28.04 7 G0 SDO, SOHO.. Last 3 CH is family by south polar CH "-" polarity; Sch - CH Square in Mm**2 (in square megameters) near the central meri- dian on http://sdowww.lmsal.com/suntoday/; n/d - no data; R - solar rotations; EE-date of possible geomag. disturbance in the Earth's environment. G(0-5)-geoeffectivity in last solar rotation on the middle latitudes. A-active geomagnetic condition. ------------------------------------------------------------------------ FROM 17.04/05 to 21/1538 UT THE EARTH IS IN "+" SECTOR OF THE INTER- PLANETARY MAGNETIC FIELD. THE FOLLOWING SECTOR BOUNDARY +/- THE EARTH HAS EXPECTED TO PASS 15.05. APRIL 17 18 19 20 21 22 23 APRIL Wus 000 012 014 026 039 029 043 F10.7 075 080 081 081 082 084 083 èbcg ÷1.1 á9.7 ÷1.3 ÷1.1 ÷1.1 ÷1.0 á9.9 GOES Sp 000 020 110 140 180 240 260 msh N 1 1 21 IMF + + + + +/- - - DSCOVR Å>2 6.7å+7 4.4å+7 2.0E+7 1.5E+7 5.1å+7 9.9å+7 1.0å+8 GOES Ie>2 1717 1129 501 546 2805 7466 20544 pfu Ap 2 5 16 33 19 58 42 nô BOULDER Dst -11 -7 -42 -55 -44 -62 -59 nô KIOTO Amsc 3 17 15 23 19 35 31 nô IZMIRAN ------------------------------------------------------------------ Å>2 - Daily Electron Fluency e/(cm2-ster-day) with E>2 MeV. Ie>2 - the maximum intensity of electron flux in geostationary or- bits in days according to GOES15 in (electrons/cm2.s.sr) for events > 1000 pfu. THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT WAS BE- GINING AT 09.04/1330 UT AND OBSERVED 9-19.04. NEXT ENHANCE WAS BEGI- NING 21.04/1425 UT AND OBSERVED AT 21-23.04. THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSTATIONARY ORBIT OF VERY HIGH LEVEL IS EXPECTED 24 - 30.04. GEOMAGNETIC CONDITION WAS UNSETTLED TILL 19.04. THE MAJOR MAGNETIC STORM (G2, Ams=51, dur.= 12 h.) WAS OBSERVED SINCE THE BEGINNING OF OF DAY 20.04 ACCORDING TO THE CENTER IN BOULDER DATA. ACCORDING TO THE IZMIRAN DATA IT WAS THE MINOR MAGNETIC STORM (G1, Ams= 28, dur. = 27 h.) WHICH HAS BEGUN 19.04/20 UT. THIS GEOMAGNETIC DISTURBATION IS CAUSED BY ARRIVAL OF INTERPLANETARY CME FROM SOLAR FILAMENT EJEC- TION 18.04 WHEN THE EARTH ALREADY ENTERED IN THE SOLAR WIND HIGH-SPE- ED STREAM FROM TRANS-EQUATORIAL CORONAL HOLE "+" POLARITY. THE FOLLO- WING MAGNETIC STORM (G2, Ams= 37, dur.= 33 h.) ACCORDING TO IZMIRAN DATA (MINOR) AND (G2, Ams ~51, dur. >60 h.) ACCORDING TO THE CENTER IN BOULDER (MAJOR) HAVE BEGUN IN THE SECOND HALF 21.04. THIS GEOMAGNE- TIC DISTURBATION PROBABLY BECAME RESULT OF ICME ARRIVAL FROM DSF 19. 04, BUT CONDITIONS OF HIS EMERGENCE AND DEVELOPMENT AREN'T CLEAR TO ME YET. NEXT WEEK GEOMAGNETIC CONDITION WILL BE ACTIVE, FROM TIME TO TIME IN- CREASING UP TO THE MINOR MAGNETIC STORM LEVEL 24 - 27.04- THE RECUR- RENT INCREASE CONNECTED WITH PASSING BY THE EARTH SOLAR WIND OF HIGH- SPEED STREAMS FROM FAMILY OF CORONAL HOLES OF POLAR CH OF THE SOUT- HERN HEMISPHERE. IN OTHER DAYS GEOMAGNETIC CONDITION WILL BE QUIET AND UNSETTLED. HIGHLIGHT AND FORECAST COMPOSED FROM DATA: NOAA SWPC, BOULDER, USA http://www.swpc.noaa.gov, THE SOLAR INFLUENCES DATA ANALYSIS CENTRE, SIDC, BRUSSELS, BELGIUM http://sidc.oma.be/index.php3, THE IZMIRAN, MOSCOW, TROITSK, RUSSIA http://www.izmiran.ru V. Ishkov