------------------------------------------------------------------- THE PHASE OF MINIMUM - 25 CYCLE OF SOLAR ACTIVITY, THE BRANCH OF RISE: Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 13 - 19.09.2021, Forecast on 20 - 27.09.2021 Carrington Rotations 2248, 2249 (28,33.08; 21,88.10.2021) Earth out of ecliptic (2.9 - 2.4) deg. (S30 - N32 is zone of geoeffectivness) THE SUNSPOT-FORMING SOLAR ACTIVITY WAS ON VERY LOW AND LOW LE- VELS AND 15-17.09 TYE SUN WAS SPOTLESS (59 DAYS AT 2021). THE ESTIMATED MOST LIKELY WEEKLY AVERAGE VALUE OF THE SUNSPOT NUM- BER IN THE INTERNATIONAL SYSTEM (old) FOR PERIOD IS W=6+13/-6 (Wn= 10+22/-10). THERE ARE 3 SMALL QUITE SUNSPOT GROUPS ON VI- SIBLE SOLAR DISK, 1 - ON NORTH HEMISPHERE) HAS BEEN OBSERVED. NEXT WEEK SUNSPOT ACTIVITY WILL BE ON LOW AND VERY LOW LEVELS. WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE IN- TERNATIONAL SYSTEM (old) FOR NEXT WEEK IS W=020+20/-10. FLARE ACTIVITY WAS AT MIDDLE AND LOW LEVELS. 4 FLARES OF X-RAY CLASS "C", 38 - CLASS "B", 3 SOLAR FILAMENT EJECTIONS AND 40 CO- RONAL MASS EJECTIONS (13-15, 17-19.09) HAVE BEEN OBSERVED. ------------------------------------------------------------------- FLARES >M1 X-RAY CLASSES to tm te local. Class E(1-8A) AR RII/IV CME X-ray/Ïp J/m-2 DSF to te localization l deg. Fl AR CME/to 13.09 0100 0200 NW-Ë×ÁÄÒÁÎÔ >10 CME/0200 18.09 1512 S39E28L159 10 19.09 1042 S38W04L054 5 CME/1336 -------------------------------------------------------------------- NEXT WEEK THE FLARE ACTIVITY IS EXPECTED AT VERY LOW AND 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 Spacecraft CH* - N20L052 N05L057 S05L056 N10L051 1.1% 27.08 R1 SDO,SOHO... * - low geoeffectivity, the substorms with duration <6 h. only. Sch - CH area in % solar hemisphere near the central meridian on https://www.solarmonitor.org/; n/d - no data; R - solar rotations; EE-date of possible geomagnetic disturbance in the Earth's environment. G(0-5)-geoeffectivity in last solar rotation on the middle latitudes. A-active geomagnetic condition. ---------------------------------------------------------------------- AFTER 18.09/0415 UT THE EARTH IS IN THE "-" SECTOR OF THE INTERPLANE- TARY MAGNETIC FIELD. FOLLOWING SECTOR BOUNDARY "-/+" IT CAN BE EXPECT 21-23.09. ----------------------------------------------------------------------- SEPTEMBER 13 14 15 16 17 18 19 SEPTEMBER Wus 032 013 000 000 000 011 013 F10.7 087 078 075 073 073 074 075 èbcg ÷2.1 ÷1.0 <÷1.0 <÷1.0 2 1.8E+6 4.9E+6 1.1E+7 1.2E+7 1.8å+6 1.2E+6 1.2E+6 GOES Ie>2 392 332 456 468 294 179 154 pfu Ap 9 6 6 3 24 5 3 nô Dst nô KIOTO Amsc 9 7 5 3 17 7 2 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 GOES-15 in (electrons/cm2.s.sr) for events > 1000 pfu. THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT NO OBSERVED. NEXT WEEK THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT IS NOT EXPECTED - NO GEOEFFECTIVE CORONAL HOLES. THE GEOMAGNETIC CONDITION WAS QUIET AND UNSETTLED ALL DAYS EXCEPT 17 - 18.09, WHEN A SUBSTORM (G1, 6 hours duration) ACCORDING TO IZMIRAN DATA, AND MINOR MAGNETIC STORM (G1, Ams= 35, dur.= 12 Þ.) HAVE BEEN OBSERVED. THE SOURCES THIS DISTURBANCES WAS SOLAR FILA- MENT EJECTION 13.09. THE NEXT WEEK IS MOST PROBABLE A QUIET AND UNSETTLED GEOMAGNETIC CONDITION ALL DAYS. 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