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Volume 58 Supplement 4

Special Issue: Swarm—The Earth’s Magnetic Field and Environment Explorers

Curl-B technique applied to Swarm constellation for determining field-aligned currents


The constellation of the Swarm satellites provides for the first time the opportunity to determine field-aligned currents in the ionosphere uniquely. This is achieved by employing the curl-B relation of Ampere’s law directly to measurements of a satellite pair flying side-by-side. The new technique is applied to a set of consistent magnetic field and current data generated by a global magnetospheric model. Using a realistic Swarm constellation the current distribution is determined along the orbit from the synthetic magnetic field data. The resulting currents are tested against the input currents. The agreement between input model and recovered field-aligned currents is excellent and much improved compared to the single-satellite estimates. Due to the spatial separation of the sampling points, only the distribution of large-scale field-aligned currents can be determined. These investigations demonstrate one important aspect of the broad capabilities provided by the upcoming space mission.


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Correspondence to Patricia Ritter.

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Ritter, P., Lühr, H. Curl-B technique applied to Swarm constellation for determining field-aligned currents. Earth Planet Sp 58, 463–476 (2006).

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Key words

  • External magnetic field
  • high latitude currents
  • field-aligned currents
  • current determination