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Space Weather in the Equatorial Ionosphere

Space Weather in the Equatorial Ionosphere. Robert Stening School of Physics, University of New South Wales. Acknowledge help from Dr J Du, IPS Radio and Space Services. Variability Source. Atmospheric Tidal Winds Driving Ionospheric Dynamo. Equatorial Electrojet. Magnetic Variations D H.

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Space Weather in the Equatorial Ionosphere

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  1. Space Weather in the Equatorial Ionosphere Robert Stening School of Physics, University of New South Wales Acknowledge help from Dr J Du, IPS Radio and Space Services

  2. Variability Source Atmospheric Tidal Winds Driving Ionospheric Dynamo Equatorial Electrojet Magnetic Variations DH Electric Field E Vertical Ion Drifts Plasma Bubbles Ion Density Gradients Equatorial Anomaly Scintillation Communication Problems GPS Problems

  3. 3m radar signal/noise (original Wes Swartz- Cornell)

  4. Vert. Drift velocities, Heights of max. backscattered power, Spread F layers. Equinox, solar maximum From Fejer et al, 1999

  5. Scintillation Occurrence at Indonesian Station (crest). 1988 Monitor results Model 1999 From Cervera et al Radio Sci 2001

  6. WAAS (Wide Area Augmentation System)

  7. What conditions are necessary for bubble formation? • Most often occurs at equinox and solar maximum. • Often inhibited by magnetic disturbance • More likely if both end of field line pass into darkness at the same time • Lasts longer into night if electric field reversal is weak

  8. Low solar flux Peru. Radar echo occurrence Medium solar flux Hysell & Burcham Clemson University High solar flux High Kp Low Kp

  9. Scintillation maximises when sunset at same time at each end of field line. From Tsunoda (1985)

  10. Modelled spread F growth rates (Du et al)

  11. What measurable parameters might help forecast bubble formation? • Vertical drifts are the main factor but not always measured • Ground-based magnetic fields as a proxy? • Need model and measure drift – DH relationship • C/NOFS satellite

  12. Modelling problems • Is equatorial electrojet controlled locally or is it part of the worldwide current system?

  13. Modelling problems • Is equatorial electrojet controlled locally or is it part of the worldwide current system? • Or a bit of both?

  14. Modelling problems • Is equatorial electrojet controlled locally or is it part of the worldwide current system? • Or a bit of both? • ►Are the day-to-day changes due to tidal changes or local wind changes?

  15. Modelling problems • Is equatorial electrojet controlled locally or is it part of the worldwide current system? • Or a bit of both? • ►Are the day-to-day changes due to tidal changes or local wind changes? • Why does latitude profile not model correctly?

  16. Trivandrum DH 120 70

  17. DH Vertical Drift Vel. Comparison of Drift velocities with DH for 11 days (10-13 LT) from Anderson et al

  18. Vertical field Points – observed Curve -simulation Northward field 86 nT added to X simulation

  19. DH DZ African chain latitude profiles

  20. Data Worldwidecomponent Model “Total” electrojet current Fambitakoye et al (1976) – African data

  21. Communication/Navigation Outage Forecasting System Launch 2003

  22. DZ Points – data Curves -simulation DY DX added 86 nT

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