On shock waves and the role of hyperthermal chemistry in the early diffusion of overdense meteor trains

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Silber , E A , Hocking , W K , Niculescu , M L , Gritsevich , M & Silber , R E 2017 , ' On shock waves and the role of hyperthermal chemistry in the early diffusion of overdense meteor trains ' , Monthly Notices of the Royal Astronomical Society , vol. 469 , no. 2 , pp. 1869-1882 . https://doi.org/10.1093/mnras/stx923

Title: On shock waves and the role of hyperthermal chemistry in the early diffusion of overdense meteor trains
Author: Silber, Elizabeth A.; Hocking, Wayne K.; Niculescu, Mihai L.; Gritsevich, Maria; Silber, Reynold E.
Contributor: University of Helsinki, Department of Physics
Date: 2017-08
Language: eng
Number of pages: 14
Belongs to series: Monthly Notices of the Royal Astronomical Society
ISSN: 0035-8711
URI: http://hdl.handle.net/10138/215218
Abstract: Studies of meteor trails have until now been limited to relatively simple models, with the trail often being treated as a conducting cylinder, and the head (if considered at all) treated as a ball of ionized gas. In this article, we bring the experience gleaned from other fields to the domain of meteor studies, and adapt this prior knowledge to give a much clearer view of the microscale physics and chemistry involved in meteor-trail formation, with particular emphasis on the first 100 or so milliseconds of the trail formation. We discuss and examine the combined physicochemical effects of meteor-generated and ablationally amplified cylindrical shock waves that appear in the ambient atmosphere immediately surrounding the meteor train, as well as the associated hyperthermal chemistry on the boundaries of the high temperature post-adiabatically expanding meteor train. We demonstrate that the cylindrical shock waves produced by overdense meteors are sufficiently strong to dissociate molecules in the ambient atmosphere when it is heated to temperatures in the vicinity of 6000 K, which substantially alters the considerations of the chemical processes in and around the meteor train. We demonstrate that some ambient O-2, along with O-2 that comes from the shock dissociation of O-3, survives the passage of the cylindrical shock wave, and these constituents react thermally with meteor metal ions, thereby subsequently removing electrons from the overdense meteor train boundary through fast, temperature-independent, dissociative recombination governed by the second Damkohler number. Possible implications for trail diffusion and lifetimes are discussed.
Subject: shock waves
Earth
meteorites
meteors
meteoroids
THERMAL-DECOMPOSITION
UPPER-ATMOSPHERE
RADIOWAVE SCATTERING
RADAR
EARTH ATMOSPHERE
ION CHEMISTRY
COSMIC DUST
DECAY TIMES
IONIZATION
ABLATION
115 Astronomy, Space science
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