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Solar and Interplanetary Sources of G eomagnetic disturbances

Solar and Interplanetary Sources of G eomagnetic disturbances. Yu.I. Yermolaev , N. S. Nikolaeva, I. G. Lodkina, and M . Yu . Yermolaev Space Research Institute (IKI - ) , RAS, Moscow, Russia

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Solar and Interplanetary Sources of G eomagnetic disturbances

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  1. Solar and Interplanetary Sources of Geomagnetic disturbances Yu.I. Yermolaev, N. S.Nikolaeva, I. G. Lodkina, and M. Yu. Yermolaev Space Research Institute (IKI - ), RAS, Moscow, Russia Several results have been published and may be found in http://www.iki.rssi.ru/people/yyermol_inf.htmlyermol@iki.rssi.ru Space Weather Effects on Humans:in Space and on Earth International Conference IKI, Moscow, June 4-8, 2012

  2. History • After Richard Carrington’s observation of strong solar flare on 1 September 1859 and strong magnetic storm in 18 hours after flare there was point of view that solar flares are sources of magnetic storms. • Modern observations showed that after most part of flares there is no magnetic storms and • many storms are observed without any solar activity.

  3. Solar flares and magnetic storms during 1976-2000

  4. Main reason of magnetospheric disturbances is negative (southward) component of Interplanetary Magnetic Field (IMF Bz < 0) • Non-disturbed solar wind contains IMF which lies in ecliptic plane => Bz =0 ! • Only disturbed types of solar wind may be geoeffective.

  5. Large-scale types of solar wind (From Yermolaev, Cos.Res.,1990; Planet. Space Sci., 1991)

  6. General concept of storm effectiveness of solar and interplanetary events Fast stream Slow stream

  7. Aims of research • Occurrence rate of different types of solar wind • Geoeffectiveness (number of selected type of solar wind resulted in magnetic storm with Dst < - 50 nT divided by total number of this type) • Efficiency (with `output/input` criteria) in generation of magnetic storms by different types of solar wind

  8. Example ofOMNI data andcalculated parametersin our databaseftp://ftp.iki.rssi.ru/pub/omni(f left)andidentification of solar wind typesftp://ftp.iki.rssi.ru/pub/omni/catalog/(ibottom)

  9. Yearly number of different types of large-scale solar wind phenomena • Heliospheric current sheet HCS ~ 124±81per year (maximum near solar minimum) • Corotating interaction region CIR ~ 63±15 (at decrease of cycle) • Interplanetary СМЕ orEjecta~ 99±38 (at increase and decrease of cycle) • Magnetic cloudМС~ 8±7 (at decrease of cycle) • Sheath beforeEjecta and МСare observed at half of Ejecta и МС (near maximum of cycle)

  10. Durationsof different types of large-scale solar wind phenomena • ~ 29±5 h for IСМЕ (Ejecta), • ~ 24±11for magnetic cloudМС, • ~ 20±4for CIR, • ~16±3 for Sheath before ICME (Ejecta), • ~ 9±5for Sheath beforeMC, • ~5±2 for HCS.

  11. Distribution of different types of solar wind during 1976-2000

  12. Distribution ofinterplanetary sources of magnetic storms

  13. Distribution ofinterplanetary sources of magnetic storms (taking data gaps into account)

  14. Distribution ofinterplanetary sources of magnetic storms

  15. Geoeffectiveness of different types of large-scale solar wind phenomena solar wind phenomena Geoeffectiveness

  16. Duration of main phases of magnetic storms and double superposed epoch method

  17. Behavior of parameters obtained by double superposed epoch method

  18. Variations of parameters obtained by double superposed epoch method

  19. Behavior of solar wind parameters in various types of streams during magnetic storms with Dst ≤ –50 nT

  20. Connection of magnetospheric indexes with Bz component of IMF

  21. Connection of magnetospheric indexes with Ey component of electric field

  22. Efficiency of various types of solar wind streams

  23. Number of events N, geoeffectiveness (probability) P and efficiency Ef=Dst/Ey

  24. Conclusions On thebasis of our «Catalog of large-scale solar wind phenomena during 1976-2000» (see data on siteftp://ftp.iki.rssi.ru/omni/ and paper by Yermolaev et al., Cosmic Research, 2009, №2) we obtained: 1. Occurrence rate of different types of solar wind: • average number: 124±81 events per yearforHCS, 8±6forМС, 99±38forEjecta, 46±19 forSheathbeforeEjecta, 6±5 forSheathbeforeМС, и 63±15forCIR; • duration of events: ~ 29±5hforEjecta,~ 24±11forМС, ~ 20±4forCIR, ~16±3 forSheathbeforeEjecta, ~ 9±5forSheathbeforeMC, ~5±2forHCS; • Time distribution:steadt types of solar wind (FAST+ SLOW + HCS) 60%,CIR10%,MC2%, EJECTA20%,Sheath9%. 2. Geoeffectiveness of events:0.613forMC, 0.142 forEjecta, 0.202forCIR, 0.633forMCwithSheath, 0.545forMCwithoutSheath, 0.212forEjecta withSheath, 0.08forEjecta without Sheath. These results are published inCosmic Research. 2009, № 5 and 2010, № 1 http://www.iki.rssi.ru/people/yyermol_inf.html yermol@iki.rssi.ru

  25. Conclusions(2) 3. Efficiency • Dependencies of Dst (orDst*) on the integral of Bz (or Ey) over time are almost linear and parallelfor different types of drivers (time evolution of main phase of storms depends not only on current values ofBz and Ey but also on their prehistory). • We estimated efficiency of storm generation as “output/input”= Dst/integated Ey(Bz) ratio. • Efficiency of storm generation by MC is the lowestone (i.e. at equal values of integrated Bz or Ey the storm is smallerthan for another drivers) and • Efficiency for Sheath is the highest one. Several results have been published in Ann.Geophys. 2010 and Journal Geophys. Res., 2012 may be found in http://www.iki.rssi.ru/people/yyermol_inf.html yermol@iki.rssi.ru

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