TY - JOUR

T1 - Field-aligned currents in the winter and summer hemispheres caused by IMF By

AU - Lukianova, R. Yu

AU - Kozlovskii, A.

AU - Christiansen, F.

PY - 2012/5/1

Y1 - 2012/5/1

N2 - Structures controlled by the IMF By sign and season of the year have been detected based on the decomposition of field-aligned current maps constructed using magnetic field measurements on polar low-orbiting satellites. It has been indicated that field-aligned currents have identical structures, composed of the main polar circular current and the return current at the polar cap dayside boundary, at any By sign in the summer hemisphere. Two different types of structures are implemented under winter conditions depending on the By sign. For the northern winter, it is the polar circular current and the return current at the polar cap nightside boundary at By <0; current sheets are strongly stretched along latitudes below 80° MLat, and only small part of the current is in the noon sector of the polar cap. For the summer winter, the corresponding structures are implemented at opposite By signs. The intensities of the field-aligned currents, originating as a result of the interhemispheric asymmetry and flowing along closed geomagnetic field lines near the polar cap boundary, have been estimated. The maximum of the interhemispheric current density is 0.25 μA m -2 in the summer and 0.1 μA m -2 in the winter; the total current is 5 × 10 5 and 5 × 10 4 A, respectively.

AB - Structures controlled by the IMF By sign and season of the year have been detected based on the decomposition of field-aligned current maps constructed using magnetic field measurements on polar low-orbiting satellites. It has been indicated that field-aligned currents have identical structures, composed of the main polar circular current and the return current at the polar cap dayside boundary, at any By sign in the summer hemisphere. Two different types of structures are implemented under winter conditions depending on the By sign. For the northern winter, it is the polar circular current and the return current at the polar cap nightside boundary at By <0; current sheets are strongly stretched along latitudes below 80° MLat, and only small part of the current is in the noon sector of the polar cap. For the summer winter, the corresponding structures are implemented at opposite By signs. The intensities of the field-aligned currents, originating as a result of the interhemispheric asymmetry and flowing along closed geomagnetic field lines near the polar cap boundary, have been estimated. The maximum of the interhemispheric current density is 0.25 μA m -2 in the summer and 0.1 μA m -2 in the winter; the total current is 5 × 10 5 and 5 × 10 4 A, respectively.

UR - http://www.scopus.com/inward/record.url?scp=84861763957&partnerID=8YFLogxK

U2 - 10.1134/S0016793212020089

DO - 10.1134/S0016793212020089

M3 - Article

AN - SCOPUS:84861763957

VL - 52

SP - 300

EP - 308

JO - Geomagnetism and Aeronomy

JF - Geomagnetism and Aeronomy

SN - 0016-7932

IS - 3

ER -