High-Frequency Radio Emission from Meteors

Abstract

A model of the processes that explain the intrinsic radio emission from meteors is proposed. A method for solving a self-similar problem of a strong explosion is used to determine certain parameters of the plasma wake dynamics at the initial expansion stages. Calculations show that this plasma expansion stage is responsible for the incoherent and unpolarized radiation from the meteor in the upper layers of the atmosphere. A theoretical estimate of the spectral density of the radio emission flux is obtained within this model, and it coincides with the experimental values. The radiation maximum is in the high-frequency range and strongly depends on the altitude and parameters of the meteor. For example, for the characteristic properties of the atmosphere at an altitude of about 90 km for a meteor with a mass of ~5 × 10^–2 kg, the spectral flux is ~2000 W/m² Hz at ~100 km from the source and the maximum is at ~40–60 MHz. According to the experiment, the radio emission spectrum drops sharply at higher frequencies.