Reflection of sound by glow discharge plasma

Abstract

The propagation of sound through temperature gradient regions of a glow discharge plasma is analysed. Using a JWKB solution known for a Schröedinger's equation describing the propagation of quantum particle through a potential barrier, an algorithm for evaluation of the reflection coefficient is proposed. The analytical results are compared with those obtained by numerically solving Euler's equations using a second order finite difference approach. The sound reflection coefficients calculated for temperature distribution profiles that are typical for atmospheric glow discharge plasma demonstrate that, at zero-incidence angle, a significant part, up to 25%, of the wave energy can be reflected. These results indicate that sound attenuation by the atmospheric glow discharge plasma by more than 10 dB, as demonstrated in a recent experiment, can be explained, accounting for three-dimensional effects, by the thermal gradient sound–plasma interaction mechanisms.