High resolution observations of 150 km echoes at Jicamarca

High resolution soundings of equatorial upper E‐region echoes at Jicamarca exhibit gravity wave modulated signal intensity distributions and Doppler velocities corresponding to vertical plasma drifts. A gravity wave wind driven interchange instability is suggested as a possible generation mechanism of the field‐aligned plasma irregularities responsible for the echoes. The echoes may be utilized in gravity wave studies and in zonal electric field measurements by radars with modest sensitivities.