Dependence of the parameters of ionospheric Alfven resonance from the conditions of Geospace by the data of synchronous observations in Antarctica and Eurasia
- critical frequency,
Among the processes in the circumterrestrial plasma what form properties of the geospace the key role belong to the electromagnetic resonances of the Earth: Schummann Resonance (SR) and Ionospheric Alfven Resonance (IAR). This is because IAR is localized in space more than SR and its properties largely depend on the characteristics of the propagation medium. In contrast to the SR, which has global nature and which is observable at any time, IAR signals are registered mostly during the night and demonstrate more variability of the parameters than SR signals. At the Earth surface IAR is registered as Spectral Resonance Structure (SRS) of the natural electromagnetic noise at frequency range 0.1-30 Гц. In this work we studied an influence of the characteristics of environment on IAR parameters by the means of multiposition observations. Annual data series recorded at Ukrainian Antarctic Station “Akademik Vernadskiy” (UAS), Low Frequency Observatory (LFO) IRA NASU near Kharkov (Ukraine) and magnetic station of Sayan Solar Observatory Mondy near Irkutsk (Russia) were used for the analysis. Authors investigated the behaviour of IAR parameters, such as probability of resonance lines registration, frequency spacing dF, for annual and diurnal intervals. These parameters were compared with characteristics of the ionosphere and magnetic fields disturbances above all the observation points. Long data sets recorded at different stations were used to verify and confirm our technique of the reconstruction of F2 layer critical frequency – f0F2 from SRS frequency spacing. Also we have detected and studied new effect of splitting of the IAR maximums on two satellites.