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Evidence of standin...
Abstract
Ämnesord
Stäng
- 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.
Ämnesord
- NATURVETENSKAP -- Fysik -- Fusion, plasma och rymdfysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Fusion, Plasma and Space Physics (hsv//eng)
Nyckelord
- 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
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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