MHD waves in the pre-front region of the interplanetary shock on May 10, 2024

The article reports on the study of the dynamics of the IMF turbulent component from the quiet period on May 7, 2024 to the arrival of an interplanetary shock wave in the second half of May 10, 2024. To achieve the stated goal, 1-minute direct measurements of interplanetary medium parameters on the ACE, DSCOVR, and WIND spacecraft are involved in the analysis. Spectral analysis methods are used to study the evolution of power spectra of fluctuations in IMF modulus and MHD waves in the inertial portion of the SW turbulence spectrum at frequencies ~2.5∙10–4–8.3∙10–3 Hz. The contribution of Alfvén, fast, and slow magnetosonic waves to the observed power spectrum of the IMF modulus measured by each of the three spacecraft is determined, and power spectra of MHD waves of these types are identified. It is shown that the power of the spectra of fluctuations in the IMF modulus and MHD waves increases by more than an order of magnitude as the shock wave approaches the point of its recording on the spacecraft. It is concluded that this is due to the generation of MHD waves by fluxes of energetic storm particles (ESP) — cosmic rays with energies ~1 MeV, observed in the region ahead of the interplanetary shock wave front. Analysis of all measurement data allows for the assumption that a significant increase in low-energy CR fluxes (~1 MeV) and SW turbulence levels may lead to a change in the IMF direction in the region adjacent to the IPS front.