Modelling the diurnal evolution of the resonance spectral structure of the atmospheric noise background in the Pc 1 frequency range

We calculate the frequency spectrum of the electromagnetic background noise in frequency range 0.1-5 Hz based on the model attributing its formation to the ionospheric resonant filtration of the radiation from distant lightning discharges (Belyaev, P.P., Polyakov, S.V., Rapoport, V.O., Trakhtengerts, V.Y., 1989. Theory of formation of the resonance spectral structure of atmospheric electromagnetic noise background in the range of short-period geomagnetic pulsations, Izvestiya vuzov-Radiofizika 32(7) 802-810). Characteristics of the spectral resonance structure (SRS) formed due to the ionospheric Alfven resonator are obtained and their dependence on ionospheric parameters is considered; the SRS variation during a day is discussed. The calculations are compared with the ULF ground based observations at Sodankyla and Nizhny Novgorod; consistency of theory and experiment is demonstrated. Opportunities to use such data to determine some of ionosphere parameters are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.