Analysis of SAMA interference on Pc3 pulsations using data from conjugate stations: a case study

Abstract. Based on a case study, we analyzed Pc3 pulsation data from pairs of conjugate stations located at low latitudes (L-shell < 2). One pair of stations is situated in the Americas under the influence area of the South Atlantic Magnetic Anomaly (SAMA). As a reference, we selected a pair of stations located at a distant longitude in the Asia-Pacific region. This choice of regions facilitates meaningful comparisons. We conducted a signal spectral analysis using the fast Fourier transform (FFT), the continuous wavelet transform (CWT), and wavelet coherence to characterize the dynamics of Pc3 pulsations at conjugate stations in the time–frequency domain. In this case study, the Pc3 pulsations exhibited similar waveforms and occurred simultaneously at the conjugate stations in both regions. Spectral power plots and wavelet scalograms revealed notable similarities between the stations. However, we observed an increase in pulsation amplitude and wavelet coefficients at the station located near the SAMA center. Additionally, high coherence and in-phase signals were observed in the Asia-Pacific region, while moderate to high coherence signals were observed at the station in the SAMA region. We suggest that the observed differences at the SAMA station may result from the unique characteristics of the region. The presence of the SAMA facilitates the precipitation of energetic particles from the inner radiation belt, thereby enhancing ionospheric conductivity.