McGranaghan, RM;
Mannucci, AJ;
Forsyth, C;
(2017)
A comprehensive analysis of multi-scale field aligned currents: Characteristics, controlling parameters, and relationships.
Journal of Geophysical Research: Space Physics
, 122
(12)
pp. 11931-11960.
10.1002/2017JA024742.
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Abstract
We explore the characteristics, controlling parameters, and relationships of multi-scale field aligned currents (FACs) using a rigorous, comprehensive, and cross-platform analysis. Our unique approach combines FAC data from the Swarm satellites and the Advanced Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) to create a database of small-scale (∼10-150 km, <1∘ latitudinal width), mesoscale (∼150-250 km, 1-2° latitudinal width), and large-scale (>250 km) FACs. We examine these data for the repeatable behavior of FACs across scales (i.e., the characteristics), the dependence on the interplanetary magnetic field (IMF) orientation, and the degree to which each scale ‘departs’ from nominal large-scale specification. We retrieve new information by utilizing magnetic latitude and local time dependence, correlation analyses, and quantification of the departure of smaller from larger scales. We find that: 1) FACs characteristics and dependence on controlling parameters do not map between scales in a straight forward manner; 2) relationships between FAC scales exhibit local time dependence; and 3) the dayside high-latitude region is characterized by remarkably distinct FAC behavior when analyzed at different scales, and the locations of distinction correspond to ‘anomalous’ ionosphere-thermosphere (IT) behavior. Comparing with nominal large-scale FACs, we find that differences are characterized by a horseshoe shape, maximizing across dayside local times, and that difference magnitudes increase when smaller scale observed FACs are considered. We suggest that both new physics and increased resolution of models are required to address the multi-scale complexities. We include a summary table of our findings to provide a quick reference for differences between multi-scale FACs.
| Type: | Article |
|---|---|
| Title: | A comprehensive analysis of multi-scale field aligned currents: Characteristics, controlling parameters, and relationships |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/2017JA024742 |
| Publisher version: | http://doi.org/10.1002/2017JA024742 |
| Language: | English |
| Additional information: | © 2017. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | Multi-scale; field aligned currents; swarm; AMPERE; magnetosphere-ionosphere coupling |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10038237 |
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