Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 18 - 24.12.2017, Forecast on 25 - 31.12.2017, Carrington Rotation 2198 (30,94.12.2017) Earth above the ecliptic (0.6 - 0.1) deg. (S30 - N30 is geoeffectiveness zone) SUNSPOT-FORMING ACTIVITY WAS ON THE VERY LOW LEVEL (18 - 19.12 -SPOTLESS, 101 SPOTLESS DAYS IN THE CURRENT YEAR) AND THE LOW AF- TER 20.12. THE ESTIMATED, MOST LIKELY WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE INTERNATIONAL SYSTEM (old) FOR THE PERIOD W= 008+5/-8 (Wn= 013+7/-13). ON THE VISIBLE SOLAR DISK ONE SMALL AND QUITE SUNSPOT GROUP HAVE BEEN OBSERVED. NEXT WEEK THE LEVEL OF SUNSPOT ACTIVITY WITH HIGH PROBABILITY WILL BE ON THE LOW AND THE VERY LOW LEVEL ON THE END OF PERIOD. LIKELY WEEKLY AVERAGE VALUE OF THE RELATIVE SUNSPOT NUMBER IN THE INTERNA- TIONAL SYSTEM (old) FOR THE NEXT WEEK IS W= 010+15/-10. THE FLARE ACTIVITY WAS AT THE VERY LOW LEVEL. 3 EJECTION OF SOLAR FILAMENT AND, ACCORDING TO DATA FROM SOHO AND STEREO CORONOGRAPHS, >5 CME HAVE BEEN OBSERVED. ---------------------------------------------------------------------- FLARES 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 21.12 >1030 >2255 S15E14L136 12 21.12 >1406 >0633 S10E03L125 20 22.12 >1453 >0715 S53E09L118 6 --------------------------------------------------------------------- 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 Space Obser. CH - N20L135 N18L137 N05L127 N08L111 12000 24.12 3 SDO, SOHO... CH - S15L065 S40L103 S60L083 S16L263 39200 26.12 8 SDO, SOHO... Last CH - from south polar CH family. 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 19.12/2300 UT THE EARTH IS IN "-" SECTOR OF THE INTERPLANETARY MAG- NETIC FIELD. NEXT SECTOR BOUNDARY -/+ EARTH SHOULD BE PASSED 0N 31.12. DECEMBER 18 19 20 21 22 24 25 DECEMBER Wus 000 000 016 018 018 022 022 F10.7 072 069 074 076 075 076 076 èbcg á4.0 á4.1 A5.6 A5.8 A6.0 A5.7 A5.7 GOES Sp 000 000 070 070 070 090 160 msh N 1 IMF + +/- - - - - - DSCOVR Å>2 1.7E+8 1.7E+8 1.7E+8 1.4å+8 1.4å+8 5.6å+7 9.3E+6 GOES Ie>2 5978 5787 4134 3763 3000 2813 1434 pfu Ap 16 6 5 3 2 5 12 nô Dst nô KIOTO Amsc 13 7 7 3 2 5 14 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 BE- GUN 17/2100 UT AND 18-24.12 WERE OBSERVED. NEXT WEEK THE GREATER THAN 2 MeV ELECTRON FLUX AT GEOSYNCHRONOUS OR- BIT IS NOT EXPECTED. GEOMAGNETIC CONDITION CHANGED FROM ACTIVE (18.12) TO UNSETTLED AND QUIET IN OTHER DAYS. ACCORDING TO THE CENTER IN BOLDERE, 17.02 MINOR MAGNETIC STORM (G1, Ams= 31, dur.= 18 h.) WHICH HAS BEGUN IN THE SE- COND HALF 17.12 , IN EAST HEMISPHERE, ACCORDING TO THE IZMIRAN DATA, SUBSTORM (G1) LASTING LESS THAN 9 h. WAS SHOWN. THERE WAS GEOMAGNE- TIC POLE REACTION ON EARTH's PASSING OF THE HIGH-SPEED STREAM FROM TRANS-EQUATORIAL CORONAL HOLE "+" POLARITY. NEXT WEEK, THE GEOMAGNETIC CONDITION WILL CHANGE FROM UNSETTLED AND QUIET IN OTHER 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