An automatic method to determine the frequency scale of the ionospheric Alfvén resonator using data from Hylaty station, Poland

Abstract. ULF/ELF magnetic field data recorded at the "Hylaty" station in Poland (49°19' N, 22°56' E; L≃2) are analysed to find the characteristics of spectral resonance structures (SRS) in the frequency range 1–5 Hz, related to the ionospheric Alfvén resonator (IAR). An automatic procedure is employed to SRS events observed at "Hylaty" during the nighttime in 2001–2003, to calculate the parameter which determines the separation between the harmonics of the resonator, termed the frequency scale. Diurnal and seasonal variations of the frequency scale within the range of 0.4–0.8 Hz have been found. The usefulness and disadvantages of this particular method of SRS analysis, and of other methods, are discussed.