Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 09 - 15.04.2018, Forecast on 16 - 23.04.2018, Carrington Rotation 2002, 2003 (22.94.03; 19,22.04.2018) Earth out of ecliptic (-2.9 - -2.5) deg. (S25 - N25 is zone o geoeffectiveness) THE SUNSPOT-FORMING ACTIVITY OF THE SUN WAS ON VERY LOW LEVEL, THE VISIBLE DISK WAS SPOTLESS 16 - 18.04 (67 d ON THE CURRENT YEAR). THE ESTIMATED, MOST LIKELY WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM (old) FOR THE PERIOD. ON THE VISIBLE DISK IT WAS OBSERVED TWO SMALL, QUI- TE SUNSPOT GROUP. ONE, BIGER, WAS FORMED IN THE NORTHERN HEMI- SPHERE (N04) ON THE REVERSE SIDE OF THE SUN HAS APPEARANCE 10. 04 AND ON THE VISIBLE DISK 18.04. AFTER 20.04 IN IT THE NEW MAGNETIC FLUX HAS APPEARED (EVOLUTIONARY), AREA IS UP TO 110 msh - FLARES OF THE X-RAY CLASS B ONLY HAVE BEEN OBSERVED. NEXT WEEK THE LEVEL OF SUNSPOT ACTIVITY WILL BE ON THE VERY LOW LEVEL. LIKELY WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM (old) FOR THE NEXT WEEK IS W=010+10/-10. FLARE ACTIVITY WAS ON THE VERY LOW LEVELS ON PERIOD. ONE EJEC- TA OF SOLAR FILAMENTS AND FOUR CORONAL MASS EJECTIONS (17 AND 21.04) HAVE BEEN OBSERVED. ---------------------------------------------------------------------- FLARES FROM M1 CLASSES to tm te local. Class E(1-8A) AR RII/IV CME X-ray/Ïp J/m-2 DSF to te localization l × ÇÒÁÄ. Fl AR CME/to 20.04 0628 0843 N45W55l279 10 --------------------------------------------------------------------- NEXT WEEK THE FLARE ACTIVITY IS EXPECTED AT 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. óî - N20L050 N17L090 S35L050 N10L002 18400 20.04 4 G0 SOHO,SDO... 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. ------------------------------------------------------------------------ AFTER 12.04/0430 UT EARTH IS IN "-" SECTOR OF INTERPLANETARY MAG- NETIC FIELD. NEXT SECTOR BOUNDARY -/+ THE EARTH MUST PASS 25.04. APRIL 16 17 18 19 20 21 22 APRIL Wus 000 000 000 014 014 034 020 F10.7 069 069 071 071 073 077 076 èbcg á1.5 á1.6 á2.7 á3.7 á5.7 á6.2 á5.3 GOES Sp 000 000 000 020 040 120 130 msh N IMF ~/- ~/- ~/- ~/- ~/- - - DSCOVR Å>2 1.8E+8 1.7E+8 1.0E+8 3.5å+7 2.8å+7 5.5å+8 8.8å+8 GOES Ie>2 6481 4585 4403 1782 2168 21310 24055 pfu Ap 2 3 5 2 42 12 6 nô Dst nô KIOTO Amsc 2 3 5 4 27 13 6 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 HAS BEGAN AT 10.04/0430 UT AND OBSERVED 10.03 - 22.04. NEXT WEEK THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT IS EXPECTED 23 - 30.04. MODERATE (G2, Ams=48, dur.=21 h.) ACCORDING CENTER IN BOULDER DATA, AND MINOR (G1, Ams=31, dur.=18 h.) ACCORDING TO IZMIRAN DATA MAGNE- TIC STORM IS REGISTERED 20.04, AS A RESULT OF COOPERATIVE IMPACT OF THE INTERPLANETARY SHOCK (SSC 19.04/2350 UT - THE SOURCE IS NOT KNOWN) AND PASSINGS BY THE EARTH OF THE SOLAR WIND HIGH-SPEED STRE- AM FROM TRANS-EQUATORIAL CORONAL HOLE. GEOMAGNETIC CONDITION WAS UNSETTLED AND QUITE IN OTHER DAYS. NEXT WEEK THE GEOMAGNETIC CONDITION SHOULD BE QUITE 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