25 CYCLE OF SOLAR ACTIVITY, THE BRANCH OF RISE: THE PHASE OF MINIMUM Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 20 - 26.09.2021, Forecast on 27.09 - 03.10.2021 Carrington Rotations 2249 (24,59.09. 2021) Earth out of ecliptic (2.3 - 1.4) deg. (S30 - N30 is zone of geoeffectiveness) THE SUNSPOT-FORMING SOLAR ACTIVITY WAS ON MIDDLE AND LOW LE- VELS. THE ESTIMATED MOST LIKELY WEEKLY AVERAGE VALUE OF THE SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM (old) FOR PERIOD IS W=37+8/-14 (Wn=62+13/-24). THERE ARE 1 MIDDLE (FLARE-ACTI- VITY) AND 7 SMALL QUITE SUNSPOT GROUPS ON VISIBLE SOLAR DISK, 2 - ON NORTH HEMISPHERE) HAS BEEN OBSERVED. NEXT WEEK SUNSPOT ACTIVITY WILL BE ON MIDDLE AND LOW LEVELS. WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE IN- TERNATIONAL SYSTEM (old) FOR NEXT WEEK IS W=040+20/-20. FLARE ACTIVITY WAS AT MIDDLE AND LOW LEVELS. 2 FLARES OF X- RAY CLASS "M", 13 -CLASS "C", 108 - CLASS "B", 1 SOLAR FILA- MENT EJECTIONS AND 15 CORONAL MASS EJECTIONS (20-26.09) HA- VE 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 23.09 0435 0442 0527 S30E22L156 1N/M2.9 1.8E-02 12871 II/2|966km/s IV/1 CME/0500 23.09 1523 1539 1608 S29E16L156 M1.8/1N 1.2E-02 12871 CME/1612 DSF to te localization l deg. Fl AR CME/to 21.09 1728 1842 N15W37L 10 -------------------------------------------------------------------- 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. AT PERIOD 21/23 - 23/12 UT WAS "+" SECTOR. FOL- LOWING SECTOR BOUNDARY "-/+" IT CAN BE EXPECT 2-3.10. ----------------------------------------------------------------------- SEPTEMBER 20 21 22 23 24 25 26 SEPTEMBER Wus 051 050 076 075 075 038 067 F10.7 080 085 085 090 088 088 086 èbcg á6.3 ÷1.0 ÷1.1 ÷1.3 B1.2 ÷1.5 A9.8 GOES Sp 280 430 420 340 250 200 170 msh N 1 2 1 2 IMF - -/+ + +/- - - - DSCOVR Å>2 1.4E+6 1.3E+6 1.6E+6 1.6E+7 4.8å+6 3.6E+6 7.8E+6 GOES Ie>2 124 174 149 1247 309 236 288 pfu Ap 3 8 12 11 8 7 3 nô Dst nô KIOTO Amsc 4 10 9 7 7 5 3 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 OBSERVED 23.09 ONLY. 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. 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