IMF By-Related Cusp Currents Observed from the Ørsted Satellite and from Ground

P. Stauning, Fritz Primdahl, J. Watermann, Ove Rasmussen

    Research output: Contribution to journalJournal articleResearchpeer-review


    Orsted is the first satellite to conduct high-precision magnetometer observations from low-altitude noonmidnight orbits passing through the polar cusp regions. Field-aligned currents (FAC) derived from Orsted magnetic field measurements have been combined with ionospheric current patterns inferred from ground-based magnetic observations to define the structure and location of cusp currents and their dependencies on interplanetary magnetic field (IMF) conditions. Example cases illustrate the close relation between IMF B-gamma-related FAC and horizontal ionospheric currents in the cusp region. Our statistical analysis defines for the noon region the variations in FAC latitude with IMF B-Z. Comparisons with the statistical cusp location indicate that the more equatorward region of IMF B-gamma-while the more B related FAC is located on field lines closing at the dayside poleward FAC are on "open" field lines. High-energy electron measurements from the satellite confirm this result.
    Original languageEnglish
    JournalGeophysical Research Letters
    Issue number1
    Pages (from-to)99-102
    Publication statusPublished - 2001


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