Author(s): Fridrich VALACH, Eduard KOČI

Title: ESTIMATING GEOMAGNETIC VARIATIONS PRODUCED BY A FIELD-ALIGNED CURRENT AT MIDDLE LATITUDES

Source: F. Filip, Zs. Gódány, Š. Gubo, E. Korcsmáros, S. Tóbiás Kosár, T. Zsigmond (eds.): 16th International Conference of J. Selye University. Sections of the Faculty of Economics and Informatics. Conference Proceedings

ISBN: 978-80-8122-509-3

DOI: https://doi.org/10.36007/5093.2024.321

Publisher: J. Selye University, Komárno, Slovakia

PY, pages: 2024, 321-329

Published on-line: 2024

Language: en

Abstract: When interpreting geomagnetic variations during magnetic storms, Fukushima's theorem must sometimes be considered. According to the theorem, any magnetic effect from the longitudinal currents (f. a. c.) cannot be observed at the Earth's surface because that magnetic effect is cancelled by the Pedersen currents diverging or converging in the ionosphere. The assumptions of this theorem are: (1) the f. a. c. is perpendicular to the conducting ionospheric layer, and (2) the conductivity of the ionosphere is homogeneous. Typical places where the assumptions of this theorem are satisfied are the places on the planet at high geomagnetic latitudes (approximately said at high geographic latitudes). In the presented work, we study some consequences of Fukushima's theorem in middle latitudes. Our conclusions are limited to estimates of indicative character since we used certain simplifying assumptions.

Keywords: geomagnetic field, field-aligned currents, Biot–Savart law, Fukushima’s theorem, ionosphere

Fulltext (PDF)