The anomalous diffusion of meteor trails

Radars frequently detect meteor trails created by the ablation of micro‐meteoroids between 70 and 120 km altitude in the atmosphere. Plasma simulations show that density gradients at the edges of meteor trails drive gradient‐drift instabilities which develop into waves with perturbed electric fields often exceeding hundreds of mV/m. These waves create an anomalous cross‐field diffusion that can exceed the cross‐field (⟂ B) ambipolar diffusion by an order of magnitude. The characteristics of the instabilities and anomalous diffusion depend on the trail altitude, latitude, and density gradient. A simple relation defines the minimum altitude at which meteor trail density gradients drive plasma instabilities and anomalous diffusion. These results impact a number of meteor radar studies, including those that use diffusion rates to determine trail altitude, and atmospheric temperature.