Towards statistical and empirical models of the distribution of VLF waves at high latitude from the observations of the Viking spacecraft
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It is of considerable interest to compile a model of the low frequency electromagnetic wave intensity across the polar caps, in and around the auroral zones, as well as at lower latitudes. Waves are playing a dynamic role in the auroral region and can be used to characterize the level of activity in the magnetosphere. At middle latitudes, Very Low Frequency (VLF) and Extremely Low Frequency (ELF) waves are known to scatter trapped energetic electrons, alter their angular and energy distributions, and eventually cause their precipitation into the Earth's atmosphere where it affects the propagation of radio signals. We report here on the development of a data-based model of the electromagnetic power spectral density in the VLF band (10-46 kHz) as surveyed onboard the Swedish Viking spacecraft in the high-latitude region in the northern hemisphere. The data have been sorted into bins according to spatial location and wave frequency. A preliminary statistical model is presented showing the mean electric power spectral density versus magnetic local time and versus invariant latitude at fixed height intervals and for fixed frequency bands within the VLF range. Our data base includes 1162 data intervals, each of 15 min lenght, during March-December 1986. As a future goal, an empirical model fitting these averages with simple analytical functions may also be developed. This work also aims to associate observed plasma wave characteristics in a particular region of the magnetosphere with geomagnetic conditions. Progress in these directions is reported.
CitationDarrouzet, F.; Spjeldvik, W.N.; Lemaire, J.F.; Gustafsson, G.; Hann, C.; Dyck, C. (2003). Towards statistical and empirical models of the distribution of VLF waves at high latitude from the observations of the Viking spacecraft. , Advances in Space Research, Vol. 32, Issue 3, 323-328, DOI: 10.1016/S0273-1177(03)90270-5.