Low-altitude meteor trail echoes

Abstract

We present here the first observations of a new type of meteor echo. These Low-Altitude Trail Echoes (LATE), observed almost exclusively below 90 km altitude using the Jicamarca Research Observatory 50 MHz radar, exhibit very different features and characteristics from the other well studied and reported meteor trails-the specular meteor trails and the Range Spread Trail Echoes. Some of these features include strong altitude dependence, low aspect sensitivity and no gap between the head echo and the trail. Perhaps most importantly, almost 80% of the head echoes below 85 km altitude in our data set exhibit LATE trails. The study of these echoes provides valuable insights into the role of diffusion and plasma instabilities in the formation and evolution of meteor trails. Copyright 2009 by the American Geophysical Union.