Longitudinal drift of choruses and their connection with magnetic disturbances on the night side of earth

VLF choruses occurring during the recovery phase of a polar substorm are characterized by a longitudinal drift manifested in the fact that the radiation is first observed at a more easterly station and then at a more westerly one in the local morning. The necessary conditions for chorus generation are the development of geomagnetic disturbances during the evening hours at a given station and the development of long-term irregular AA micropulsations, as well as the presence of magnetic disturbances on the night side of earth during the chorus observed in the morning sector.