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Yurdanur Tulunay Tolga Yapıcı

Effects of IMF B z reversals on the Ionospheric Critical Frequencies (f 0 F2) between 1975 and 1986. Yurdanur Tulunay Tolga Yapıcı Department of Aerospace Engineering, Middle East Technical University. Content. Introduction Objectives Datasets Criteria for “ Superposed Epoch” Results

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Yurdanur Tulunay Tolga Yapıcı

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  1. Effects of IMF Bz reversals on the Ionospheric Critical Frequencies (f0F2) between 1975 and 1986 Yurdanur Tulunay Tolga Yapıcı Department of Aerospace Engineering, Middle East Technical University COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  2. Content • Introduction • Objectives • Datasets • Criteria for “Superposed Epoch” • Results • Conclusion • Future Work COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  3. Introduction IMF Bz component Most of the features of the Earth’s magnetosphere and high latitude ionosphere COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  4. Objectives • Investigate the probable effects of IMF Bz on f0F2, • Search the role of geomagnetic conjugacy, • To validate the previously published results. COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  5. Datasets • Ionospheric Critical Frequencies: AZ163 - KG24R, SO166 • Geomagnetic Index: Kp • Interplanetary Magnetic Field COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  6. Criteria for “SuperPosed Epoch” • The Geomagnetically quiet times:3 Hour Planetary Kp Index • Kp≤2+ • Event Definition: IMF Bz • Southward polarity change, • | ΔIMF Bz | > 11 nT, • Polarity should be same for 3 hours before the event • Polarity should be same for 3 hours after the event COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  7. Results – I [Davis et al., 1997] COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  8. Results – II [Davis et al., 1997] COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  9. Results – III(Control Curves) [Tulunay et al., 2001] COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  10. Results – IV(f0F2 distributions AZ163) COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  11. Results – V(f0F2 distributions KG24R) COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  12. Results –VI(f0F2 distributions SO166) COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  13. Results – IV (AZ163) COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  14. Results – V(SO166) COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  15. Conclusion • f0F2 variabilitydue to IMF Bz reversals have been studied. • Due to events, tendency of ~1 MHz decrease in δ(f0F2). COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  16. Discussion – I COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  17. Discussion – II COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  18. Future Work • Develop a model of the ionospheric variability under the IMF By and IMF Bz dynamics. COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  19. Acknowledgement • Thanks to; • TÜBİTAK ÇAYDAG • COST 724 • Matthew Wild at the World Data Center COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  20. References • Tulunay, Y., “Interplanetary magnetic field and its possible effects on the mid-latitude ionosphere II”, Annali di Geofisica, 37/2, (1994) • Tulunay, Y., “Interplanetary magnetic field and its possible effects on the mid-latitude ionosphere III”, Annali di Geofisica, 39/4 (1996) • Davis, J. D., Wild, M. N., Lockwood, M., Tulunay, Y., “Ionospheric and geomagnetic responses to changes in IMF Bz: a superposed epoch study”, Annales Geophysicae, 15, 217-230 (1997) • O. A. Troshichev, “Plasma pressure and the field aligned currents in the magnetosphere”, Advances in Space Sciences, 33, 729-736 (2005) • Nelson C. Maynard, “Coupling The Solar-Wind/IMF To The Ionosphere Through The High Latitude Cusps”, Surveys in Geophysics, 26: 255–280 (2005) • J. Merka, J. Safrankova, Z. Nemecek and J. Sımunek, “Magion-4 High-Altitude Cusp Study”, Surveys in Geophysics, 26: 57–69 (2005) • For Data: • http://spidr.ngdc.noaa.gov/spidr/index.jsp • World Data Centre at Rutherford • Matthew Wild COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

  21. Thanks for listening... COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

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