Magnetospheric Pc5 pulsation generated by interplanetary shocks during the geomagnetic storms

In this study, we conduct a comprehensive investigation of magnetospheric ultralow frequency (ULF) Pc5 (2–7 mHz) waves that occurred during the geomagnetic storms of 22 June 2015, 17 March 2015, and 7 September 2017. These events presented a unique opportunity to analyze the characteristics and behavior of ULF waves in the magnetosphere, as they are closely linked to various geophysical phenomena, including magnetospheric dynamics and ionospheric responses. We employ continuous wavelet analyses to investigate the time-frequency characteristics of Pc5 ULF waves. Analysis reveals the presence of Pc5 pulsations during the arrival of interplanetary shocks. Cross-correlation analysis shows that Pc5 pulsations are positively correlated with interplanetary magnetic field (IMF), solar wind speed (Vsw), proton number density (Nsw), and solar wind pressure (Psw). Similarly, the AE index and Polar Cap index also show a positive correlation. These observations indicate that due to a sudden increase in solar wind velocity and proton number density after the interplanetary shock, gradually increasing solar wind dynamic pressure and a sudden compression from the Earth’s dayside magnetosphere, results in ULF Pc5 waves being generated in the magnetosphere.