Rocket‐borne wave, field, and plasma observations in unstable polar cap E‐region

Abstract

This paper presents initial results from the first comprehensively instrumented rocket flown through a Farley‐unstable polar cap E‐region. Groundbased ionosondes and magnetometers at two locations and HF radar backscatter at the launch site were used to determine the presence of a geographically widespread ionospheric plasma instability. The observed wave direction, electric field, and current density fit the predictions of the linear theory of the Farley instability, whereas the gradient‐drift instability seems to be excluded by the geometry of the observations.