The effect of geomagnetic activity changes on the ionospheric critical frequencies (foF2) at magnetic conjugate points

• Main Authors: Timoçin, Erdinç, Ünal, İbrahim, Tulunay, Yurdanur, Göker, Ümit Deniz
• Format: Article in Journal/Newspaper
• Language: English
• Published: ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND 2018
• Subjects: Ionospheric critical frequency; Geomagnetic activity; Magnetic conjugate; Superposed epoch analysis; Brisbane; Resolute Bay; Scott Base
• Online Access: https://hdl.handle.net/11363/7223

In this work, we investigate the possible effects of geomagnetic activity on the ionospheric critical frequencies (foF2) in geomagnetic conjugate points. For this purpose, hourly foF2 data measured for the year 1976 from the ionosonde stations Akita, St. John’s and Resolute Bay in the Northern hemisphere and their corresponding magnetic conjugate ionosonde stations Brisbane, Halley Bay and Scott Base in the Southern hemisphere are examined. Planetary geomagnetic activity ‘‘3h-Kp” indices are used as a geomagnetic activity indicator. foF2 data in the magnetic conjugate points (MCP) are investigated by using a superposed epoch analysis method. This analysis is done depending on the response of foF2 to geomagnetic activity variations in MCP based on geomagnetic stormy days around equinoxes (March 21, September 23) and solstices (June 21, December 21), and the results obtained from these MCP are compared. From these results, it is found that foF2 values in magnetic conjugate pairs give similar reactions to geomagnetic activity variations simultaneously, although this relationship differs according to the seasons and magnetic latitudes of the stations.