On the Plasma-Dust Processes Accompanying Meteor Showers

Plasma-dust processes in the Earth's ionosphere related to transit of meteor bodies and spreading of meteor trail are analyzed. Processes that occur in the meteor trail itself and those taking place in the Earth's atmosphere upon transit of a meteor body, along with their influence on observers and operation of various technical systems, are investigated. In particular, mechanisms explaining acoustic phenomena accompanying meteor transit during meteor showers are proposed. The mechanism of formation of dusty plasma in meteoroid trails is described. It is demonstrated that charging of dust particles of the meteoroid material creates conditions for the appearance of dust acoustic waves. Dust acoustic perturbations are driven as a result of development of modulation instability of electromagnetic waves emitted by the meteor trail and have frequencies typical of dust sound (0.003-60 Hz). The reports of witnesses revealed that observers on the Earth can hear low-frequency sounds appearing during meteor showers. It is suggested that the sound reaches the Earth's surface as a result of transfer of oscillations from dust particles to neutrals the concentration of which in the atmosphere is high. The mechanisms of fragmentation of meteor bodies and charging of formed dust particles are analyzed. Characteristic charges of dust fragments for nano- and micrometer-scale particles are estimated. Particles of different shape are considered. The growth rates that give rise to modulation excitation of low-frequency dust acoustic perturbations are calculated. Conditions leading to development of a modulation instability are found.