Abstract <p>This work analyzes the electromagnetic mechanism of interaction between subsystems in the Earth–atmosphere–ionosphere–magnetosphere (EAIM) system. The study is based on a system of equations for the volumetric density of electromagnetic energy and the total electron content of high-energy electrons in the magnetic flux tube, which describes the resonant interaction between waves and particles at the cyclotron frequency. The purpose of this work is to obtain analytical solutions to the system of equations describing the interaction of powerful electromagnetic radiation with high-energy magnetospheric electrons and to numerically model the main parameters of this interaction. Solutions for both the stationary and nonstationary problems have been obtained. Aperiodic and quasi-periodic modes of disturbances have been identified. The value of the stationary relative disturbance of total electron content, as a function of the particle and electromagnetic radiation source parameters, has been calculated. The dependence of various magnetospheric and ionospheric parameters on the electron and electromagnetic radiation source parameters has been determined. The radiation from a single lightning strike can lead to significant electron flux densities (~10⁵–10¹¹ m^–2 s^–1). In this case, the electron density in the ionosphere can increase from tens of percent to several hundred times. The disturbance of the geomagnetic and ionospheric electric fields, caused by ionization bursts in the ionosphere, has been calculated. The amplitude of geomagnetic field disturbances ranged from fractions to hundreds of nanoteslas, while the electric field disturbance varied from 10 μV to 100 mV. Secondary effects in the EAIM system, caused by the electromagnetic mechanism of disturbances, are briefly discussed.</p>