The longitudinal polar cusp displacement from geomagnetic measurements in Antarctica

Martina Marzocchetti, Stefania Lepidi, Patrizia Francia, Lili Cafarella, Domenico Di Mauro


We used ULF geomagnetic field measurements in the Pc5 frequency range (1.7-7 mHz) attwo Antarctic stations to statistically investigate the longitudinal location of the polar cusp.The two stations are located at the same geomagnetic latitude, ~80° S (just poleward of thecusp), and are separated by one hour in magnetic local time. Since at each station the Pc5power maximizes when the station approaches the cusp, the comparison between their Pc5power allows to estimate the longitudinal position of the cusp and to examine its movements.We found that there is a displacement of the cusp depending on interplanetary conditions;in particular, the cusp shifts to later hours for negative values of the interplanetary magneticfield and solar wind velocity east-west components (By and Vy), while moves to earlier hoursfor positive values of Vy. Conversely, no dependence of the cusp longitudinal position onpositive By values nor on the interplanetary magnetic field north-south component (Bz) emerges.               


Magnetospheric physics; Structure and dynamics; Geomagnetic field variations and reversals; Solar-terrestrial interaction; Space weather

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Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN: 2037-416X