Modulational Interaction in a Dusty Plasma of Meteoroid Wakes

This is a study of the possible modulational instability of electromagnetic waves in meteoroid wakes associated with the dust acoustic mode at altitudes of 80–120 km, which is a linear stage of modulational interaction. The parameters of meteoroid wakes at different altitudes in the Earth’s ionosphere are considered. It is shown that the charging of dust particles of meteoric matter creates conditions for the occurrence of dust acoustic waves. Dust acoustic disturbances are excited due to the modulational instability of electromagnetic waves from the meteoric trail. The influence of neutrals on the development of modulational interaction is taken into account. The concentration of neutrals in meteoric wakes is higher than the concentration of neutrals in the Earth’s ionosphere. It has been found that the condition for the excitation of a dust acoustic wave is satisfied for the typical parameters of dusty plasma of meteoroid wakes at altitudes of 100–120 km. Due to collisions between dust and neutrals, the development of modulation instability is suppressed at altitudes of 80–90 km, while inelastic collisions of neutrals with electrons and ions do not affect the development of modulational instability. The modulational instability of electromagnetic waves can explain the occurrence of low-frequency noise during the passage of meteoric bodies in a frequency range characteristic of dust acoustic waves. It is shown that the modulation instability has time to develop for characteristic temperatures and particle concentrations in meteoroid wakes. Equations for the charging of dust particles in meteoroid wakes are given. It has been found that the dust is positively charged, both in the daytime and at night, due to intense emission currents from the surface of dust particles.