Dipolar elementary current systems for ionospheric current reconstruction at low and middle latitudes

Heikki Vanhamäki, Astrid Maute, Patrick Alken, Huixin Liu

Research output: Contribution to journalArticlepeer-review

Abstract

The technique of spherical elementary current systems (SECS) is a powerful way to determine ionospheric and field-aligned currents (FAC) from magnetic field measurements made by low-Earth-orbiting satellites, possibly in combination with magnetometer arrays on the ground. The SECS method consists of two sets of basis functions for the ionospheric currents: divergence-free (DF) and curl-free (CF) components, which produce poloidal and toroidal magnetic fields, respectively. The original CF SECS are only applicable at high latitudes, as they build on the assumption that the FAC flow radially into or out of the ionosphere. The FAC at low and middle latitudes are far from radial, which renders the method inapplicable at these latitudes. In this study, we modify the original CF SECS by including FAC that flow along dipolar field lines. This allows the method to be applied at all latitudes. We name this method dipolar elementary current systems (DECS). Application of the DECS to synthetic data, as well as Swarm satellite measurements are carried out, demonstrating the good performance of this method, and its applicability to studies of ionospheric current systems at low and middle latitudes. [Figure not available: see fulltext.].

Original languageEnglish
Article number146
Journalearth, planets and space
Volume72
Issue number1
DOIs
Publication statusPublished - Dec 1 2020

All Science Journal Classification (ASJC) codes

  • Geology
  • Space and Planetary Science

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