1. SCHOOL OF PHYSICS 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

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

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6. 3m radar signal/noise (original Wes Swartz- Cornell)

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

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

9. SCHOOL OF PHYSICS WAAS (Wide Area Augmentation System)

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11. 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

12. SCHOOL OF PHYSICS Low Kp High Kp Low solar flux Medium solar flux High solar flux Peru. Radar echo occurrence Hysell & Burcham Clemson University

13. SCHOOL OF PHYSICS From Tsunoda (1985) Scintillation maximises when sunset at same time at each end of field line.

14. SCHOOL OF PHYSICS Modelled spread F growth rates (Du et al)

15. SCHOOL OF PHYSICS 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 –  H relationship C/NOFS satellite

16. SCHOOL OF PHYSICS Modelling problems Is equatorial electrojet controlled locally or is it part of the worldwide current system?

17. SCHOOL OF PHYSICS Modelling problems Is equatorial electrojet controlled locally or is it part of the worldwide current system? Or a bit of both?

18. SCHOOL OF PHYSICS 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?

19. SCHOOL OF PHYSICS 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?

20. SCHOOL OF PHYSICS Trivandrum  H 70 120

21. SCHOOL OF PHYSICS HH Vertical Drift Vel. Comparison of Drift velocities with  H for 11 days (10-13 LT) from Anderson et al

22. SCHOOL OF PHYSICS Vertical field Northward field Points – observed Curve -simulation 86 nT added to X simulation

23. SCHOOL OF PHYSICS HH ZZ African chain latitude profiles

24. SCHOOL OF PHYSICS Fambitakoye et al (1976) – African data “Total” electrojet current Worldwide component Data Model

25. SCHOOL OF PHYSICS Communication/Navigation Outage Forecasting System Launch 2003

26. SCHOOL OF PHYSICS ZZ YY  X added 86 nT Points – data Curves -simulation

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