Evidence of standing waves during a Pi2 pulsation event observed on Cluster
2006 (English)In: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 24, no 10, 2719-2733 p.Article in journal (Refereed) Published
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 similar to 13.5.
Place, publisher, year, edition, pages
2006. Vol. 24, no 10, 2719-2733 p.
magnetospheric physics, MHD waves and instabilities, plasmasphere, storms and substorms, pi-2 pulsations, power spectra, magnetic pulsations, ulf pulsations, field-line, geomagnetic micropulsations, geosynchronous orbit, hydromagnetic-waves, inner magnetosphere, substorm onsets
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:kth:diva-16157ISI: 000242402000023ScopusID: 2-s2.0-33751099046OAI: oai:DiVA.org:kth-16157DiVA: diva2:334199
QC 201507272010-08-052010-08-052015-07-27Bibliographically approved