Spatial domain interferometric VHF radar observations of spread meteor echoes

Abstract

This paper is concerned with short lived (<2 s) meteor trails which produced VHF radar echoes, spread in range >10 km. The Doppler spectrum of these echoes in each range bin is very broad and asymmetric with many discrete peaks. Spatial domain Interferometer observations of Spread Meteor Echoes were made at the Indian National MST Radar Facility to locate the echoing regions on the trail producing the discrete peaks in the broad Doppler spectra of each range bin. We report that the mean direction of arrival was found to be similar for all Doppler frequencies in each range bin and varies for successive bins by much less than one degree. The echoing regions on the trail are located nearly parallel to the radar beam direction. Further, the directions of arrival were found to be not necessarily normal to the geomagnetic field. The observations are discussed in terms of ionization structures developed within the meteor trail.