Nonspecular meteor trail altitude distributions and durations observed by a 50 MHz high-power radar

摘要

High-power large-aperture (HPLA) radars frequently observe nonspecular meteor trail echoes that result from plasma turbulence driven by the intense pressure gradients on the trail edges. This paper analyzes the altitude range, duration, and dependence on head echo strength of nonspecular trails using two large data sets from the 50 MHz HPLA radar at the Jicamarca Radio Observatory. Over 2100 trails were used to build altitude profiles that extend from 86 km to 120 km altitude, with 97% of events occurring between 90 km and 110 km. Longer-duration trails tend to form at lower altitudes than shorter-duration echoes. The peak of the altitude distribution of trails lasting at least 5 s can be up to 12 km lower than the peak of the distribution of trails shorter than 5 s. Further, the data show a clear power law relationship for the frequency of both head echo and nonspecular trail power. An improved knowledge of nonspecular trails will allow researchers to better understand meteor trail evolution and their use in monitoring lower thermospheric winds.