Compressional Pc3-4 magnetic pulsations in the topside ionosphere: observations from multiple LEO satellites

Pc3-4 magnetic pulsations within the 16-100 mHz frequency range are mainly driven by the upstream waves (UWs) in the Earth’s foreshock region, which serves as a critical link for transferring energy from the solar wind into the magnetosphere-ionosphere system. High-precision magnetometer data from low Earth orbit (LEO) satellites, like CHAMP, Swarm and MSS-1, covering two solar cycles (from 2001-2025), provide a good database for resolving the characteristics of UWs. In this report, we performed a comprehensive analysis on UWs in the topside ionosphere, including their dependences on solar wind and interplanetary magnetic field conditions, season, magnetic local time, as well as latitude and longitudes. In addition, by analyzing the simultaneously measurements from these satellites with certain spatial separation, the propagation of UWs in the topside ionosphere has also been discussed.