Modelling high-power large-aperture radar meteor trails

Abstract

Despite decades of research, many questions remain about the global flux of meteoroids at Earth, their influence on the atmosphere, and their use as upper atmospheric diagnostics. We see high-power large-aperture (HPLA) radar observations of meteor phenomena called head echoes and non-specular trails as a valuable tool for answering these questions. In the past we conducted plasma simulations demonstrating that meteor trails are unstable to growth of Farley–Buneman gradient-drift (FBGD) waves that become turbulent and generate large B-field aligned irregularities (FAI). These FAI result in reflections called non-specular meteor trails. Using these and other results, we have developed a model that follows meteor evolution from ablation and ionization through the creation of radar head echoes and non-specular trail reflections. This paper presents results from this model, showing that we can reproduce many aspects of these large radar observations, such as the general altitude profile of head echoes and non-specular trails. Additionally we show that trail polarization due to E-fields or neutral winds causes a noticeable trail feature as well as may be responsible for trails lasting longer than about 1 s. We also demonstrate how such a model is a valuable tool for deriving meteoroid properties such as flux, mass, and velocity. Finally, such a model could also provide some composition information, and diagnose the atmosphere and ionosphere where meteors produce their trails.