Journal cover Journal topic
Annales Geophysicae Sun, Earth, planets, and planetary systems An interactive open-access journal of the European Geosciences Union
Ann. Geophys., 36, 595-607, 2018
https://doi.org/10.5194/angeo-36-595-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Regular paper
05 Apr 2018
Quantifying the relationship between the plasmapause and the inner boundary of small-scale field-aligned currents, as deduced from Swarm observations
Balázs Heilig1,2 and Hermann Lühr2 1Mining and Geological Survey of Hungary, Tihany Geophysical Observatory, 8237, Tihany, Hungary
2GFZ German Research Centre for Geosciences, Section 2.3 “Geomagnetism”, 14473 Potsdam, Germany
Abstract. This paper presents a statistical study of the equatorward boundary of small-scale field-aligned currents (SSFACs) and investigates the relation between this boundary and the plasmapause (PP). The PP data used for validation were derived from in situ electron density observations of NASA's Van Allen Probes. We confirmed the findings of a previous study by the same authors obtained from the observations of the CHAMP satellite SSFAC and the NASA IMAGE satellite PP detections, namely that the two boundaries respond similarly to changes in geomagnetic activity, and they are closely located in the near midnight MLT sector, suggesting a dynamic linkage. Dayside PP correlates with the delayed time history of the SSFAC boundary. We interpreted this behaviour as a direct consequence of co-rotation: the new PP, formed on the night side, propagates to the dayside by rotating with Earth. This finding paves the way toward an efficient PP monitoring tool based on an SSFAC index derived from vector magnetic field observations at low-Earth orbit.
Citation: Heilig, B. and Lühr, H.: Quantifying the relationship between the plasmapause and the inner boundary of small-scale field-aligned currents, as deduced from Swarm observations, Ann. Geophys., 36, 595-607, https://doi.org/10.5194/angeo-36-595-2018, 2018.
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This paper presents a statistical study of the equatorward boundary of small-scale field-aligned currents (SSFACs) as observed by ESA's Swarm satellites and investigates the relation between this boundary and NASA’s Van Allen probe observed plasmapause (PP). It is found that the two boundaries are closely coincident in the midnight LT sector, where the new PP is formed. Our results point to the role of SSFACs in the creation of the PP and offer a unique tool to monitor PP dynamics.
This paper presents a statistical study of the equatorward boundary of small-scale field-aligned...
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