25 CYCLE OF SOLAR ACTIVITY, THE BRANCH OF RISE: THE PHASE OF MINIMUM Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 04 - 10.10.2021, Forecast on 11 - 18.10.2021 Carrington Rotations 2249 (24,59.09. 2021) Earth out of ecliptic (0.5 - -0.5) deg. (S30 - N30 is zone of geoeffectiveness) THE SUNSPOT-FORMING SOLAR ACTIVITY WAS ON LOW LEVELS. THE ES- TIMATED MOST LIKELY WEEKLY AVERAGE VALUE OF THE SUNSPOT NUM- BER IN THE INTERNATIONAL SYSTEM (old) FOR PERIOD IS W= 13+13/ -5 (Wn = 22+16/-9). THERE WERE FOUR SMALL INACTIVE SUNSPOT GROUPS ON VISIBLE SOLAR DISK, THREE - ON N-HEMISPHERES)HAS BE- EN OBSERVED. NEXT WEEK SUNSPOT ACTIVITY WILL BE ON LOW AND MIDDLE LEVELS. WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE IN - TERNATIONAL SYSTEM (old) FOR NEXT WEEK IS W=040+20/-30. FLARE ACTIVITY WAS AT MIDDLE AND LOW LEVELS. 1 FLARES OF X- RAY CLASS "M", 6 - CLASS "C", 70 - CLASS "B", 1 SOLAR FILA- MENT EJECTIONS AND 12 CORONAL MASS EJECTIONS (4, 7, 9, 10.10) 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 09.10 0619 0638 0722 N17E09L158 M1.6/2B 1.5E-2 12882 II/3|934 IV/3 CME/0712 DSF to te localization l deg. Fl AR CME/to 08.10 0738 0811 N29W65L096 6 -------------------------------------------------------------------- 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 * - 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. ---------------------------------------------------------------------- 05.10/0530 UT THE EARTH IS IN THE "+" SECTOR OF THE INTERPLANETARY MAG- NETIC FIELD. FOLLOWING SECTOR BOUNDARY "-/+" IT CAN BE EXPECT 16.10. ----------------------------------------------------------------------- OCTOBER 04 05 06 07 08 09 10 OCTOBER Wus 029 027 022 013 013 014 038 F10.7 084 082 086 086 092 081 085 èbcg á9.9 á8.9 ÷1.1 á9.9 B1.0 ÷1.1 ÷1.1 GOES Sp 410 320 260 230 240 280 300 msh N 2 IMF - -/+ + + + +/- -/+ DSCOVR Å>2 2.1E+6 3.6E+6 1.4E+6 1.2E+6 1.1å+6 1.3E+6 1.1E+6 GOES Ie>2 271 248 185 118 136 155 155 pfu Ap 6 5 8 5 4 5 9 nô Dst nô KIOTO Amsc 6 4 8 4 2 3 14 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. Pr>10 MeV: 09/~14; max 09/~20 - 1.31pfu; continued... THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT NOT 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 BUT AT THE END OF DAY 10.10 IZMIRAN MAGNETOGRAFS NOTED 3-hour SUBSTORM INTENSBTY (G1). THE NEXT WEEK 12 - 13.10 IS HIGHLY PROBABLE TO EXPECT A MAGNETIC STORM OF INTENSITY UP G2 DUE TO THE ARRIVAL OF THE DISTURBATION FROM THE SOLAR FLARE M1.6 9.10. IN OTHER DAYS MOST PROBABLE QUIET AND UNSETTLED GEOMAGNETIC CONDITION. 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