Abstract
Radars detect plasma trails created by the billions of small meteors
that impact the Earth’s atmosphere daily, returning data used to infer
characteristics of the meteoroid population and upper atmosphere.
Researchers use models to investigate the dynamic evolution of the
trails, enabling them to better interpret radar results. This paper
presents a fully kinetic, 3D code to explore the impacts of three trail
characteristics: length, neutral wind speed, and ablation altitude. The
simulations characterize the turbulence that develops as the trail
evolves and these are compared to radar data. They also show that
neutral winds drive the formation of waves and turbulence in trails, and
that wave amplitudes increase with neutral wind speed. The finite trail
simulations demonstrate that the bulk motion of the trail flows with the
neutral wind. A detailed analysis of simulated trail spectra yield
spectral widths, and evaluate signal strength as a function of aspect
angle. Waves propagate primarily along the length of the trail in all
cases, and most power is in modes perpendicular to
$\mathit{\vec{B}}$. Persistent waves
develop at wavelengths corresponding to the gradient scale length of the
original trail. Our results show that the rate at which power drops with
respect to aspect angle in meter-scale modes increases from $5.7$
dB/degree to $6.9$ dB/degree with a 15 km increase in altitude. The
results will allow researchers to draw more detailed and accurate
information from non-specular radar observations of meteors.