Latitudinal expansion of Pc5 wave activity detected by SuperDARN radar, GPS TEC, and ground magnetometers associated with solar wind dynamic pressure

Singh R.; Lee Y.-S.; Jee G.; Hussey G.C.; Kim Y.H. · Journal of the Korean Physical Society (2026) · DOI: 10.1007/s40042-026-01709-2

Resumen

This study provides wide coverage for the Pc5 ultra-low frequency discrete spectrum observed in the magnetosphere and high-to-lower latitude ionosphere during noon hours (~ 10–14 MLT) on November 4, 2021. During the recovery phase, magnetospheric toroidal mode oscillations (GOES-16 Bn) appeared in response to dayside solar wind dynamic pressure enhancements during high solar wind speeds. At the same time, the super dual auroral radar network at Saskatoon recorded oscillations in both ionospheric line-of-sight velocity and echo power at discrete frequencies of 1.7 and 2.2 mHz (9.8 and 7.5 min). The geomagnetic field components exhibited the same frequency pulsations from high to lower latitudes. The oscillation frequency of the H-component persisted consistently at 1.7 mHz to the lower latitudes. Similar wave oscillations were noticed in the total electron content (TEC) of the Global Positioning System (GPS). The complex demodulation analysis suggests that the observed Pc5 oscillations are consistent with toroidal mode Alfvén waves and field line resonances (FLRs) during the storm recovery phase. The observations indicate a possible association with solar wind dynamic pressure enhancements under high-speed solar wind conditions, while cavity/waveguide modes and magnetopause Kelvin–Helmholtz instability (KHI) may have contributed to the excitation of the observed waves. © The Korean Physical Society 2026.