Аннотация:The sudden commencement of superstorm of May 10, 2024 was observed at 17:06 UT, when a strong interplanetary shock hit the Earth such that the solar wind dynamic pressure jumped to about Pd = 50 nPa and Bz component of interplanetary magnetic field (IMF) became strong negative (~-20 nT) as show in Fig. 1. The main phase was developed until 02:20 UT on 11 May and the storm reached maximum with the storm index SYM-H = -512 nT. During the main phase, the IMF Bz was negative most of time with brief reversals. The solar wind pressure stayed strong and exhibited several sharp increases and decreases which were manifested in corresponding variations of SYM-H index. During the main phase, the forbidden zone at low latitudes was temporally populated by energetic electrons and protons. The forbidden zone extends in ~20° vicinity of the dip equator excepting the region of South Atlantic Anomaly (SAA) located in the longitudinal sector from 100W to 0E. In the forbidden zone, energetic charged particles are quasi-trapped, i.e. during their azimuthal drift in the geomagnetic field they inevitable come to the SAA region where the magnetic field lines descend to very low heights such that energetic charged particles loss the energy in ionization of the dense atmosphere. Hence, energetic charged particles can be considered as an additional source of ionization of the ionosphere and upper atmosphere [1].1. Golubkov M.G., Suvorova A.V., Dmitriev A.V. et al. Effect of high-intensity electron and proton fluxes on a low-latitude ionosphere // Russ. J. Phys. Chem. B 2020. V. 14. No 10. P. 873-882. DOI: 10.1134/S1990793120050206.
