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An analysis of the 23 rd Solar Cycle’s High Speed Solar Wind Streams activity:

National and Kapodistrian University of Athens Physics Department Nuclear and Particle Physics Section. An analysis of the 23 rd Solar Cycle’s High Speed Solar Wind Streams activity:. sources of radiation hazards in Geospace. Xystouris G. Sigala E. Prof. Mavromichalaki H.

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An analysis of the 23 rd Solar Cycle’s High Speed Solar Wind Streams activity:

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  1. National and Kapodistrian University of Athens Physics Department Nuclear and Particle Physics Section An analysis of the 23rd Solar Cycle’sHigh Speed Solar Wind Streams activity: sources of radiation hazards in Geospace Xystouris G. Sigala E. Prof. Mavromichalaki H. Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  2. Presentation Outline • High Speed Solar Wind Streams (HSSWSs) and their nature • What is an HSSWS? • Potential Hazards for the Earth • HSSWSs in 23rd Solar Cycle • Categories of HSSWSs • The table of HSSWSs in the 23rd Solar Cycle • Distributions regarding their parameters • Conclusions Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  3. HSSWSs and their nature What is an HSSWS? • Intriligator, 1977:a rapidly increase of solar wind speed and a peak velocity equal or greater than 450km/s. • Bame, 1976 and Gosling, 1976: an observed variation of solar wind speed having an increment of at least 150 km/s within a 5–day interval. • Broussard, 1977: a period in which the solar wind speed is equal or greater than 500 km/s, averaged over a day. • Lindblad, 1981: a period in which the velocity difference between the smallest 3–hr velocity value and the largest 3–hr value of the following day is equal or greater than 100 km/s and it lasts for at least two days. • Mavromichalaki et al, 1988; 1998: The difference between the maximum velocity and the mean plasma velocity between the speeds immediately preceding and following the stream is equal or greater than 100 km/s, in a period lasting for at least two days. Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  4. The definition of an HSSWS in this work: (Lindblad and Lundstedt, 1981; Mavromichalaki et al. 1988, 1999) The difference (ΔV) between the maximum velocity (Vmax) and the mean plasma velocity of the speed immediately preceding and following the stream (V0) is equal or greater than 100 km/s, in a period lasting for at least two days. ΔV= Vmax - V0 ≥ 100km/s & Δt ≥ 2 days Why? • It is more adequate for the purpose of solar-terrestrial studies • It is in agreement with our previous studies Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  5. ΔV≥100km/s Δt≥2 days Typical Example of a HSSWS: Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  6. Sources of HSSWSs Corotating Streams Produced by the Coronal Holes (CH), in Quiet Areas N ~ 1/V |B| ~ V T ~ V Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  7. Flare Generated Streams Produced by Flares activity (FG), in Active Areas * * Also, generated by CMEs V, |B|, N, T: simultaneous increase with large variations T, N: independent of V SOHO – May 2, 1998EIT 195Å, X1 Flare Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  8. Potential Hazards for Earth The HSSWSs contain very energetic particles, which are the source of the solar radiation. Hazards are encounter in two areas: Geospace └ Hazard for satellites (technological instruments) and astronauts Earth’s atmosphere and ground └ Maximum danger for aircrafts’ passengers └ Possible hazards for human health on the ground (many indications from several studies) due to the radiation interaction with Earth, inside and outside its atmosphere. Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  9. HSSWSs in the 23rd Solar Cycle (May 1996 – December 2008) Categories of HSSWSs • Based on structure: • Simple HSSWS • HSSWS with Multiple Peaks • HSSWS with Data Gaps • Interrupted HSSWS (duration less than 2 days) • └ Interruption in Ascending Phase • └ Interruption in Descending Phase • Based on the existence of another HSSWS: → Cases of Consecutive HSSWSs Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  10. Schematically each category b) HSSWS with Multiple Peaks c) HSSWS with Data Gaps a) Simple HSSWS d) Interrupted HSSWS e) Case of Consecutive HSSWSs (example of CH) (example of FG) Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  11. Sunspot Number Source: OMNIWeb database (http://omniweb.gsfc.nasa.gov/ow.html) Phases of 23rd Solar Cycle Minimum Jan. 2007 – Dec. 2008 Ascending Phase May 1996 – Apr. 1999 Maximum May 1999 – Dec. 2002 Descending Phase Jan. 2003 – Dec. 2006 Extreme Solar Events July 14, 2000 April 15-18, 2001 October 28-29, 2003 November 4 & 20, 2003 January 20, 2005 December 13, 2006… General remarks for the 23rd Solar Cycle: • Very energetic Solar Cycle • Extended Solar Activity in the Descending Phase • Secondary Maximum • Extended Minimum Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  12. Table of the 23rd Solar Cycles’ HSSWSs: Sources: OMNIWeb database (http://omniweb.gsfc.nasa.gov/ow.html) National Space Science Data Center database (http://solarscience.msfc.nasa.gov/) National Oceanic and Atmospheric Administration (ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SOLAR_FLARES/FLARES_XRAY/) Maris O., Maris G., 2005; Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  13. General data of HSSWSs during the phases of 23rd Solar Cycle: Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  14. Total Number of HSSWSs throughout the 23rd Solar Cycle:  Peak flux of HSSWSs in 2003 (Descending Phase of the 23rd Solar Cycle). Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  15. Duration of HSSWSs throughout the 23rd Solar Cycle: Mavromichalaki H., VassilakiA., 1998 Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  16. Maximum Speed of HSSWSs throughout the 23rd Solar Cycle: • The mean speed of the HSSWSs increases during the Solar Cycle. Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  17. Sources of HSSWSs throughout the 23rd Solar Cycle: • Many CH HSSWSs, throughout the Cycle. Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  18. Conclusions • A number of 710 HSSWSs in Solar Cycle 23 (434 CH, 261 FG/CME, 15 unidentified sources) • The FG HSSWSs follow the expected distribution in the 23rd Solar Cycle (with the exception of 1999). However the number of CH HSSWSs is high throughout the Solar Cycle, especially in its Descending Phase. • Peak flux of HSSWSs in 2003 (73 HSSWSs), in the Descending Phase of the 23rd Solar Cycle. • The greatest ratio of Consecutive HSSWSs appears in the Maximum of the 23rd Solar Cycle (151 out of 214 – 71%) followed closely by the ratio of the Descending Phase (162 out of 239 – 68%). • Average Duration of HSSWSs for the 23rd Solar Cycle: 3-5 days • └ Duration in Maximum: 4-6 days • └ Duration in Descending Phase: 2-4 days • Maximum Speed is increasing during the 23rd Solar Cycle, even beyond Maximum • └ Vmax in Ascending Phase: 400-500 km/s • └ Vmax in Maximum: 500-600 km/s • └ Vmax in Descending Phase: 600-700 km/s → (Cycle’s largest speed: 1189 km/s) • └ Vmax in Minimum: 600-700 km/s Space Weather Effects on Humans: in Space and on Earth Space Research Institute, Moscow, RussiaJune 4-8, 2012

  19. Thank you Cпасибо ISS Expedition 30

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