MHD Waves in Solar Wind Plasma during Geomagnetic Storm Events in February–March 2023

A study of MHD waves in solar wind plasma during two geoeffective space weather events in February–March 2023 is reported. At that time, various geophysical phenomena were observed on Earth: intense magnetic storms, decreases in the intensity of galactic cosmic rays, auroras, and a number of other manifestations of space weather. To study the situation in near-Earth outer space, we used data from direct measurements of the parameters of the interplanetary medium with the DSCOVR and ACE spacecraft. The application of spectral analysis methods to the data of direct measurements of the solar wind parameters onboard the DSCOVR spacecraft made it possible to study the characteristics and dynamics of Alfén, fast, and slow magnetosonic waves in the inertial frequency range (from ∼0.0001 to ∼0.01 Hz) of the observed solar wind turbulence spectrum during these events.