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

1

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

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,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

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

6

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

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

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).

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

dynamicsdynamics.

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...