Perpendicular particle simulation of the E region Farley‐Buneman instability

Abstract

We study the stabilization and nonlinear quasi‐steady state of the E region Farley‐Buneman waves. We limit ourselves to the two‐dimensional, fully perpendicular case. We use a two‐dimensional explicit particle simulation code with neutral collisions. Since both perpendicular coordinates are included, we can study the dependence of temporal power spectra and backscattered power on flow angle. Unlike fluid simulation codes in general, the present method is not limited to small ambient electric field values. It is found that the phase velocity roughly obeys the linear theory: no saturation to the ion acoustic speed is seen. However, the spatial power spectrum is asymmetric as a function of the flow angle if the electric field is above the Farley‐Buneman threshold. This nonzero flow angle propagation is the most important new result. The most intense waves propagate at the k · E < 0 edge of the linearly unstable sector, with phase velocity close to the ion acoustic speed. No evidence of anomalous perpendicular wave heating is found.