Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 19 - 25.10.2020, Forecast on 16.10 - 02.11.2020, Carrington Rotation 2236, 2237(05,01.10; 1,31.11.2020) Earth out of ecliptic (6.4 - 6.0) deg. (S20 - N35 is zone of geoeffectiveness) THE SUNSPOT-FORMING SOLAR ACTIVITY REMAINED ON VERY LOW LEVEL. ESTIMATED, MOST LIKELY WEEKLY AVERAGE VALUE OF THE SUNSPOT NUM- BER IN THE INTERNATIONAL SYSTEM (old) FOR PERIOD W=7+10/-7 (Wn= 12+16/-12). ON VISIBLE SOLAR DISK TWO SMALL SUNSPOT GROUPS HAVE BEEN ODSERVED. NEXT WEEK THE LEVEL OF SUNSPOT ACTIVITY WAS ON VERY LOW LEVEL. LIKELY WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM (old) FOR NEXT WEEK IS W =010+10/-10. FLARE ACTIVITY WAS AT LOW AND VERY LOW LEVEL. 14 SOLAR FLARE OF VERY LOW X-RAY CLASS CLASS "B", 27-CLASS "A", ONE SOLAR FILAMENT EJECTA AND 5 CORONAL MASS EJETIONS (21, 22 é 24.10) HAVE BEEN OB- SERVED. ------------------------------------------------------------------- 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 23.10 1302 ~1720 N37E60L169 >10 -------------------------------------------------------------------- NEXT WEEK THE FLARE ACTIVITY IS EXPECTED AT VERY LOW LEVEL. ON THE VISIBLE SOLAR DISK THE FOLLOWING CORONAL HOLES WERE OBSERVED: --------------------------------------------------------------------- sign N end E end S end W end Sch EE R G Sp/craft óî - S20E02L190 S35E11L199 S38E02L190 S22W12L176 4.3 20.10 1 SOHO... CH + Pn N30W00L108 N28W00L083 N30W25L083 7.9 24.10 3 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. ---------------------------------------------------------------------- FROM 18.10/01 UT, THE EARTH IS IN THE "+" SECTOR OF THE INTERPLANETA- RY MAGNETIC FIELD, BUT 20-23.10 OBSERVED THE "-" SECTOR. THE FOLLOWING THE NEXT SECTOR BOUNDARY "+/-" IT CAN BE EXPECT 3.11. ---------------------------------------------------------------------- OCTOBER 19 20 21 22 23 24 25 OCTOBER Wus 012 011 011 011 011 011 011 F10.7 075 075 074 075 072 072 074 èbcg A3.6 A2.8 A2.0 A2.1 A2.0 2 6.9E+6 1.8å+6 4.5E+6 1.6E+6 1.0E+7 1.7E+7 1.5å+8 GOES Ie>2 772 131 251 168 621 916 5668 pfu Ap 6 4 10 6 12 17 15 nô Dst nô KIOTO Amsc 8 4 7 6 13 16 21 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 GOES-15 in (electrons/cm2.s.sr) for events > 1000 pfu. THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT BEGUN 25.10/1320 AND OBSERVED 25.10. NEXT WEEK THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT IS EXPECTED 26.10 - 05.11. A MINOR MAGNETIC STORM (G0, Ams= 27, dur.= 40 h) REGISTERED 23-24. 10 BY DATA OF THE CENTER IN BOULDER, HOWEVER, ACCORDING BY IZMIRAN DATA AT THIS TIME A SUBSTORM OF INTENSITY (G1) WITH A DURATION OF 6 h. WAS OBSERVED. WITH THE SECOND MINOR MAGNETIC STORM (G1, Ams= 33, dur.= 32 h.) ACCORDING IZMIRAN DATA, SITUATION DIRECTLY OPOSI- TE: IN BOULDER CENTER OBSERVED ONLY 9 h. SUBSTORM OF (G0) INTENSI- TY. THIS DISTURBATION IS A CONSEQUENCE OF THE IMPACT ON THE MAGNE- TOSPHERE OF THE HIGH-LATITUDE CORONAL HOLE (+) HIGH SPEED STREAM OF THE NORTHERN HEMISPHERE. IN OTHER DAYS THE GEOMAGNETIC CONDI- TION REMAINED QUIET AND UNSETTLED. NEXT WEEK IN THE FIRST TWO DAYS TO POSSIBLE WATCHES ACTIVE GEOMAG- NETIC CONDITION DUE TO THE ONGOING EFFECTS OF HIGH SPEED STREAM FROM ABOVE-MENTIONED CORONAL HOLE. IN OTHER DAYS THE MOST PROBABLY QUIET AND UNSETTLED GEOMAGNETIC CONDITION WILL BE OBSERVED. 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