Skip to content


  • Article
  • Open Access

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

Earth, Planets and Space200658:BF03351942

  • Received: 15 November 2004
  • Accepted: 1 June 2005
  • Published:


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.

Key words

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