A case study of a radially polarized Pc4 event observed by the Equator-S satellite

R. Cramm (1) , K. H. Glassmeier (1) , C. Othmer (1) , K. H. Fornacon (1) , H. U. Auster (1) , W. Baumjohann (2) , E. Georgescu (2, 3)

1 Institut für Geophysik und Meteorologie [Braunschweig]
2 MPE - Max-Planck-Institut für Extraterrestrische Physik
3 ISS - Institute of Space Science [Bucharest-Măgurele]

A 16 mHz Pc4 pulsation was recorded on March 17, 1998, in the prenoon sector of the Earth's magnetosphere by the Equator-S satellite. The event is strongly localized in radial direction at approximately L = 5 and exhibits properties of a field line resonance such as an ellipticity change as seen by applying the method of the analytical signal to the magnetic field data. The azimuthal wave number was estimated as m \approx 150. We discuss whether this event can be explained by the FLR mechanism and find out that the change in ellipticity is more a general feature of a localized Alfvén wave than indicative of a resonant process.

Domaines: Océan, Atmosphère; Sciences de la Terre

R. Cramm, K. H. Glassmeier, C. Othmer, K. H. Fornacon, H. U. Auster, et al.. A case study of a radially polarized Pc4 event observed by the Equator-S satellite. Annales Geophysicae, 2000, 18 (4), pp.411-415. ⟨hal-00316616⟩