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Abstract Processes in the radiation belts under extreme geomagnetic conditions involve the interplay between acceleration and loss processes, both of which can be caused by wave‐particle interactions. Whistler mode waves play a critical role in these interactions, and up to now their properties during extreme events remained poorly sampled and understood. We employ extensive databases of spacecraft observations to specify their distribution. We show that under extreme geomagnetic conditions, lower‐band whistler mode chorus waves have a net effect of accelerating ultra‐relativistic electrons, which results in an increase of fluxes at multi‐MeV energies by several orders of magnitude. During future magnetic superstorms, the radiation levels in the outer zone could therefore experience a substantial increase beyond what has been previously observed during the space age.

Abstract Lightning strikes can be routinely observed by the radio receivers that measure electromagnetic signals in the very low frequency range. The acquired pulses called atmospherics provide valuable details about source lightning discharges and also about the Earth‐ionosphere waveguide where they can propagate thousands of kilometers. The automatic acquisition of the events requires also automatic methods for extraction of atmospherics' details to confirm the observed trends with statistical significance. For this purpose, we have developed a method based on a deep learning approach to automatically obtain the type of atmospherics, their exact time, and the frequency range from the frequency‐time spectrograms. The method that employs convolutional neural networks is designed to be adaptable to scientific needs and provide reliable results according to the requirements on the sensitivity to events, computation performance, and precision of extracted details. The efficiency and specific steps of our method are demonstrated for data recorded by the ELMAVAN‐G instrument. The comprehensive description of the method allows its usage for regular characterization of the ionospheric D‐layer or for other similar applications in the future.