Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 1.490 IF 1.490
  • IF 5-year value: 1.445 IF 5-year
    1.445
  • CiteScore value: 2.9 CiteScore
    2.9
  • SNIP value: 0.789 SNIP 0.789
  • IPP value: 1.48 IPP 1.48
  • SJR value: 0.74 SJR 0.74
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 88 Scimago H
    index 88
  • h5-index value: 21 h5-index 21
Volume 16, issue 2
Ann. Geophys., 16, 140–147, 1998
https://doi.org/10.1007/s00585-998-0140-8
© European Geosciences Union 1998
Ann. Geophys., 16, 140–147, 1998
https://doi.org/10.1007/s00585-998-0140-8
© European Geosciences Union 1998

  28 Feb 1998

28 Feb 1998

Ionospheric conductance distribution and MHD wave structure: observation and model

F. Budnik, M. Stellmacher, K.-H. Glassmeier, and S. C. Buchert F. Budnik et al.
  • Institut für Geophysik und Meteorologie, Technische Universität Braunschweig, Germany

Abstract. The ionosphere influences magnetohydrodynamic waves in the magnetosphere by damping because of Joule heating and by varying the wave structure itself. There are different eigenvalues and eigensolutions of the three dimensional toroidal wave equation if the height integrated Pedersen conductivity exceeds a critical value, namely the wave conductance of the magnetosphere. As a result a jump in frequency can be observed in ULF pulsation records. This effect mainly occurs in regions with gradients in the Pedersen conductances, as in the auroral oval or the dawn and dusk areas. A pulsation event recorded by the geostationary GOES-6 satellite is presented. We explain the observed change in frequency as a change in the wave structure while crossing the terminator. Furthermore, selected results of numerical simulations in a dipole magnetosphere with realistic ionospheric conditions are discussed. These are in good agreement with the observational data.

Key words. Ionosphere · (Ionosphere · magnetosphere interactions) · Magnetospheric physics · Magnetosphere · ionosphere interactions · MHD waves and instabilities.

Publications Copernicus
Download
Citation