Evidence that meteor trails produce a field-aligned scatter signal at VHF

A number of workers have reported on aspect-sensitive radio echoes received from field-aligned ionization at E-layer height. While the detailed character of the signals reported varies widely, the preferred height of origin is in the upper part of the E layer near 110 km. In this paper we give evidence that meteor trails released at this height also exhibit a marked field-aligned scattering effect. We suggest that in this height region, where collision frequency relinquishes its hold on the diffusion process, there is a strong tendency to set up field-aligned irregularities in electron density, and that a number of sources can provide the necessary electrons in excess of the ambient, e.g. meteors, auroras, and sporadic E.