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A tool for improved space weather predictions: the CME expansion speed.

Max-Planck-Institut für Aeronomie Katlenburg-Lindau Germany. Instituto Nacional de Pesquisas Espaciais Sao Jose dos Campos - SP Brazil. A tool for improved space weather predictions: the CME expansion speed. A. Dal Lago , R. Schwenn. Sept. , 2001. Space Weather.

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A tool for improved space weather predictions: the CME expansion speed.

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  1. Max-Planck-Institut für Aeronomie Katlenburg-Lindau Germany Instituto Nacional de Pesquisas Espaciais Sao Jose dos Campos - SP Brazil • A tool for improved space weather predictions: • the CME expansion speed. A. Dal Lago, R. Schwenn Sept. , 2001

  2. Space Weather Geophysical Research Letters / 15 July 1998

  3. Space Weather Shock

  4. Space Weather Shock Sun: EIT / CME L1: shock - sheath - magnetic cloud Earth: geomagnetic storm

  5. Coronal Mass Ejections - CME EIT 195 EIT 195 LASCO C2 LASCO C2 LASCO C3 LASCO C3 Limb Halo

  6. Coronal Mass Ejections - CME LASCO C2 LASCO C3 Limb CME Halo CME

  7. Acceleration/Deceleration of CMEs Sept. 28, 1997 LASCO C2

  8. Acceleration/Deceleration of CMEs Sept. 28, 1997 LASCO C3

  9. Acceleration/Deceleration of CMEs S85W

  10. Acceleration/Deceleration of CMEs July 25, 1999 LASCO C3 S75E S85E S70W S55W S85W

  11. Halo CMEs from Jan. 1997 to Apr. 2001

  12. Sun: EIT / CME L1: shock - sheath - magnetic cloud Earth: geomagnetic storm Halo CMEs and Interplanetary association

  13. Sun: EIT / CME L1: shock - sheath - magnetic cloud Earth: geomagnetic storm Interplanetary signatures and CME association

  14. Sun: EIT / CME L1: shock - sheath - magnetic cloud Earth: geomagnetic storm Halo CMEs and geomagnetic storms

  15. CME expansion speed LASCO C3 LASCO C3 LASCO C3 Vexp Vpr Vpr Vrad Vexp Vexp

  16. Vexp Vrad Limb CMEs 57 events from 1997 to 2001 Criterion: EIT 195 activity close to the limb (maximum 30 deg.).

  17. Halo CMEs Vpr Vexp Frontal speed x travel time Expansion speed x travel time Vfr

  18. Halo CMEs Vpr Vexp Frontal speed x travel time Expansion speed x travel time Vfr

  19. Full halos only Ago. 25th 2001

  20. Ago. 25th 2001 Ago. 25th 2001 EIT 195 LASCO C2 LASCO C3

  21. Solwind CMEs and Helios 1 Period: 1979 - 1982 56 events - 45 where Vcme and Vip were possible to be obtained. Helios 1 + 32 degr. Solwind coronagraph

  22. Solwind and Helios 1 • Solwind: Vcme • Vexp • Solwind + Helios: travel time • -avg. propagation speed • - travel time to 1 AU Vexp 1 AU Helios1 Vcme

  23. Expansion speed x shock speed at 1AU

  24. Propagation speed x shock speed at 1AU

  25. Conclusions • Limb CMEs show a linear relation between Vexp and Vrad • There is a good correlation found between the expansion • speed (Vexp) of halo CMEs and the travel time to 1 AU. • The halo expansion speed (Vexp) can now be used to predict the • travel time of CMEs. • There is still substantial uncertainty, indicating that processes • occurring during the “trip” of the CMEs from the sun to 1 AU • may play an important whole. • 4 out of 81 full front side halo CMEs never reachead • the earth - false alarms! • 12 out of 146 transient IP shocks were not related to any • CME - prediction missed! • 1 out of 30 intense storms and 4 out of 78 moderate storms • were not related to any CME - storm prediction missed! • All very intense (Dst<-200 nT) were related to halo CMEs.

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