Yurdanur Tulunay Tolga Yapıcı

COST 724 MCM, Antalya, TURKEY, 27-30/03/2006

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Effects of IMF Bz reversals on the Ionospheric Critical Frequencies (f0F2)

between 1975 and 1986

Yurdanur TulunayTolga Yapıcı

Department of Aerospace Engineering, Middle East Technical University


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Content

Introduction Objectives Datasets Criteria for “Superposed Epoch” Results Conclusion Future Work


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Introduction

IMF Bz component

Most of the features of the Earth’s magnetosphere and high latitude ionosphere


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Objectives

Investigate the probable effects of IMF Bz on f0F2,

Search the role of geomagnetic conjugacy,

To validate the previously published results.


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Datasets

Ionospheric Critical Frequencies:

AZ163 - KG24R,AZ163 - KG24R,

SO166SO166

Geomagnetic Index:

KpKp

Interplanetary Magnetic Field

Name CodeGeom. Lat.

Geom. Long.

Arkangelsk AZ163 60.38 N 117.54 E

Kerguelen Islands

KG24R 58.47 S 121.83 E

Sodankyla SO166 63.74 N 107.68 E


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Criteria for “SuperPosed Epoch”“SuperPosed Epoch”

The Geomagnetically quiet times:3 Hour Planetary Kp Index3 Hour Planetary Kp Index

1. Kp≤2+

Event Definition:IMF BIMF Bzz

1. Southward polarity change,2. | ΔIMF Bz | > 11 nT,3. Polarity should be same for 3 hours before the event4. Polarity should be same for 3 hours after the event


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Results – I

[Davis et al., 1997]


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Results – II

[Davis et al., 1997]


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Results – III (Control Curves)

[Tulunay et al., 2001]


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Results – IV (f0F2 distributions AZ163)


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Results – V (f0F2 distributions KG24R)


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Results –VI (f0F2 distributions SO166)


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Results – IV (AZ163)


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Results – V (SO166)


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Conclusion

ff00F2 variabilityF2 variability due to IMF BIMF Bzz reversals reversals have been studied.

Due to events, tendency of ~1 MHz~1 MHz decrease in δ(f0F2).


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Discussion – I


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Discussion – II


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Future Work

Develop a modelmodel of the ionospheric variabilityvariability under the IMF BIMF Byy and IMF B and IMF Bzz

dynamicsdynamics.


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Acknowledgement

Thanks to;

– TÜBİTAK ÇAYDAG– COST 724– Matthew Wild at the World Data Center


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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


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Yurdanur Tulunay Tolga Yapıcı

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