Day to night variation in meteor trail measurements: Evidence for a new theory of plasma trail evolution

Abstract

A recent theory of meteor trail plasma diffusion made the prediction that meteors will generate more and longer lasting non-specular echoes at night than during the day. This letter presents the first evidence of a dramatic day to night difference in non-specular meteor trail occurrence rates and their duration. These observations were made by the 50MHz radar at the Jicamarca Radio Observatory (JRO) in Peru. In one 20 minute period starting 95 minutes before sunrise, this radar detected 1288 head echoes and 341 trails while a similar time after dawn, it measured 1240 head echoes but only 50 trails. Also, the duration of the nighttime trails greatly exceeded the daytime ones. This pattern was confirmed by a second experiment in July 2007. This data provides strong evidence that it is necessary to account for the effect of the ionospheric plasma density to explain meteor diffusion. Copyright 2008 by the American Geophysical Union.