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Mike Lockwood (Space Science and Technology Department, STFC Rutherford Appleton Laboratory

The Space Environment in the Inner Heliosphere. Mike Lockwood (Space Science and Technology Department, STFC Rutherford Appleton Laboratory & Southampton University) 4 th European Space Weather Week, 9 th November 2007. ROUGH GUIDES. THE ROUGH GUIDE to. The Moon & Mars.

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Mike Lockwood (Space Science and Technology Department, STFC Rutherford Appleton Laboratory

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  1. The Space Environment in the Inner Heliosphere Mike Lockwood (Space Science and Technology Department, STFC Rutherford Appleton Laboratory & Southampton University) 4th European Space Weather Week, 9th November 2007

  2. ROUGH GUIDES THE ROUGH GUIDE to The Moon & Mars • Health in Deep Space • Galactic Cosmic Rays (GCRs): stochastic effects • Solar Energetic Particles (SEPs): acute affects • Past space climate and the space weather forecast

  3. ROUGH GUIDES THE ROUGH GUIDE to The Moon & Mars • Health in Deep Space • Galactic Cosmic Rays (GCRs): stochastic effects • Solar Energetic Particles (SEPs): acute affects • Past space climate and the space weather forecast

  4. 102 10-1 10-4 10-7 10-10 10-13 10-16 10-19 10-22 10-25 10-28 Solar modulated GCRs Flux (m-2 sr-1 s-1 GeV-1) 109 1012 1015 1018 1021 Energy (eV) Galactic Cosmic Rays Solar Modulation ►Mass spectrum shows protons up to iron ions & heavier ►Low dose levels – give stochastic effects (e.g. lifetime cancer risk) rather than acute radiation sickness ►High energy/mass particles produce fragments in shielding

  5. GCR shielding at sunspot minimum Shielding GCRs Cell Transformations, C Dose Equivalent, H 2.5 2.0 1.5 1.0 0.5 0 Lead Copper Iron Aluminum Water Lithium hydride Liquid Methane Liquid Hydrogen 2.5 2.0 1.5 1.0 0.5 0 C(T) / C(T=0) H(T) / H(T=0) 0 5 10 15 20 25 30 0 5 10 15 20 25 30 T (gm cm-2) T (gm cm-2) ►Traditional dosimetric analysis - H = D  RBE ►Repair kinetics model – uses track structure injury coefficients & repair rates (Shimmerling et al., 1996)

  6. ROUGH GUIDES THE ROUGH GUIDE to The Moon & Mars • Health in Deep Space • Galactic Cosmic Rays (GCRs): stochastic effects • Solar Energetic Particles (SEPs): acute affects • Past space climate and the space weather forecast

  7. The Apollo Missions

  8. Instantly fatal Severe radiation sickness Severe radiation sickness Raised cancer risk Raised cancer risk Above annual dose Above annual dose Instantly fatal Average annual dose at Earth’s surface Max. annual dose for a radiation worker SEPs: just how lucky were the lunar astronauts? •  SEPs during the era of the Apollo Missions

  9. ► fluxes ahead of shock intersection are limited by the scattering effect of waves ► gives 12-36 hrs warning of main SEP event 103 102 100 10-1 F>60MeV (cm-2sr-1s-1) 104 103 102 101 100 10-1 T = 1 gm cm-2 of Al T = 2 gm cm-2 of Al T = 5 gm cm-2 of Al T = 10 gm cm-2 of Al Effective Skin Dose (cSv) T = 50 gm cm-2 of Al T = 250 gm cm-2 of Al 2 3 4 5 6 7 8 9 10 11 12 Day of August 1972

  10. The Bastille Day Storm CME seen by SoHO/Lasco C2 and C3 Coronographs “Halo” (Earthbound) form most easily seen in C2 difference movie ►

  11. The Bastille Day Storm GCRs and SEPs (GLE) Neutron Monitor counts ►Ground-level enhancement (GLE) of SEPs seen between Forbush decreases of galactic cosmic rays caused by shielding by the two CMEs ►Here seen at stations in both poles (McMurdo and Thule) nm counts GLE Forbush decrease caused by 1st CME Forbush decrease caused by CME associated with GLE

  12. The Bastille Day Storm SEP Proton Aurora – seen by Image FUV-SI12

  13. ROUGH GUIDES THE ROUGH GUIDE to The Moon & Mars • Health in Deep Space • Galactic Cosmic Rays (GCRs): stochastic effects • Solar Energetic Particles (SEPs): acute affects • Past space climate and the space weather forecast

  14. Polar Cap NO From SEP event of April 2002 ► Northern hemisphere ► Southern hemisphere TIMED observations of 5.3 m NO radiative fluxes (Wm2) (Mlynczak et al., 2003)

  15. Major SEP Events From nitrates in polar ice sheets ► SEP (>30MeV) fluence from ice sheet data (McCracken, 2001) ► Open flux model from sunspot number (Solanki et al., 2000) ► Open flux derived from aa index (Lockwood et al., 1999)

  16. SEP events from Ice Core nitrate data ► big SEP events at intermediate open flux (McCracken, 2007)

  17. ►McCracken (2005, 2007) proposes that at low solar activity number and speed V of CMEs increases with increasing activity ►but at highest activity large open flux FS gives large IMF B which reduces Alfvén Mach number V(o)1/2/B and hence shock strength

  18. Interplanetary SEP data > 60 MeV proton fluxes ► corrected using Climax GCR data (Lockwood, 2007)

  19. Interplanetary SEP data > 60 MeV proton fluxes ► open flux FS from observations of radial IMF FS = (4R12Br) / 2 ► use 27-day mean of Br ► daily means of >60MeV proton fluxes, F>60MeV ► GCRs (in black) anticorrelate with FS ► SEPs (in red) rare at high FS

  20. Interplanetary SEP events > 60 MeV proton fluences ► largest fluence events at intermediateopen flux FS

  21. Interplanetary SEP events Fluence > 2  108 cm-2

  22. Interplanetary SEP events Fluence > 2  108 cm-2

  23. running mean over T=[9:(1/4):13] yrs running mean over T=L yrs Recent trends - revealed by means over solar cycle length, L ►sunspot number, R ►solar cycle length, L ►FSfrom IMF data ►GCR counts C (Climax n.m.) ►PMOD composite of TSI data

  24. Conclusions ► SEP events pose a real health hazard to astronauts outside Earth’s magnetosphere ► Shielding possible and possible to issue warnings to seek shelter ► Issuing “all clears” important ► Declining open solar flux indicates that large SEP events may become more common over the next few decades

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