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|Title:||High-latitude HP Doppler observations of ULF waves. 1. Waves with large spatial scale sizes|
|Authors:||Wright, D. M.|
Yeoman, T. K.
Chapman, P. J.
|Publisher:||European Geosciences Union (EGU), Copernicus Publications, Springer Verlag (Germany)|
|Citation:||ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES, 1997, 15 (12), pp. 1548-1556|
|Abstract:||A quantitative study of observations of the ionospheric signatures of magnetospheric ultra low frequency (ULF) waves by a high-latitude (geographic: 69.6°N 19.2°E) high-frequency Doppler sounder has been undertaken. The signatures, which are clearly correlated with pulsations in ground magnetometer data, exhibit periods in the range 100–400 s and have azimuthal wave numbers in the range 3–8. They are interpreted here as local field line resonances. Phase information provided by O- and X-mode Doppler data support the view that these are associated with field line resonances having large azimuthal scale sizes. The relative phases and amplitudes of the signatures in the Doppler and ground magnetometer data are compared with a model for the generation of Doppler signatures from incident ULF waves. The outcome suggests that the dominant mechanism involved in producing the Doppler signature is the vertical component of an E × B bulk motion of the local plasma caused by the electric field perturbation of the ULF wave.|
|Rights:||Archived with reference to SHERPA/RoMEO and publisher website. © European Geosciences Union 1997. Version of record: http://www.ann-geophys.net/15/1548/1997/angeo-15-1548-1997.html|
|Appears in Collections:||Published Articles, Dept. of Physics and Astronomy|
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