%0 Journal Article
%T Evidence of standing waves during a Pi2 pulsation event observed on Cluster
%A A. B. Collier
%A A. R. W. Hughes
%A L. G. Blomberg
%A P. R. Sutcliffe
%J Annales Geophysicae (ANGEO)
%D 2006
%I Copernicus Publications
%X Observations of Pi2 pulsations at middle and low latitudes have been explained in terms of cavity mode resonances, whereas transients associated with field-aligned currents appear to be responsible for the high latitude Pi2 signature. Data from Cluster are used to study a Pi2 event observed at 18:09 UTC on 21 January 2003, when three of the satellites were within the plasmasphere (L=4.7, 4.5 and 4.6) while the fourth was on the plasmapause or in the plasmatrough (L=6.6). Simultaneous pulsations at ground observatories and the injection of particles at geosynchronous orbit corroborate the occurrence of a substorm. Evidence of a cavity mode resonance is established by considering the phase relationship between the orthogonal electric and magnetic field components associated with radial and field-aligned standing waves. The relative phase between satellites located on either side of the geomagnetic equator indicates that the field-aligned oscillation is an odd harmonic. Finite azimuthal Poynting flux suggests that the cavity is effectively open ended and the azimuthal wave number is estimated as m~13.5.  Full Article (PDF, 2546 KB)    Citation: Collier, A. B., Hughes, A. R. W., Blomberg, L. G., and Sutcliffe, P. R.: Evidence of standing waves during a Pi2 pulsation event observed on Cluster, Ann. Geophys., 24, 2719-2733, doi:10.5194/angeo-24-2719-2006, 2006.   Bibtex   EndNote   Reference Manager    XML
%U http://www.ann-geophys.net/24/2719/2006/angeo-24-2719-2006.html