Theory for planetary exospheres: II. Radiation pressure effect on exospheric density profiles
File(s)
Published version
Author(s)
Beth, A
Garnier, P
Toublanc, D
Dandouras, I
Mazelle, C
Type
Journal Article
Abstract
The planetary exospheres are poorly known in their outer parts, since the neutral densities are low compared with the instruments detection capabilities. The exospheric models are thus often the main source of information at such high altitudes. We present a new way to take into account analytically the additional effect of the radiation pressure on planetary exospheres. In a series of papers, we present with an Hamiltonian approach the effect of the radiation pressure on dynamical trajectories, density profiles and escaping thermal flux. Our work is a generalization of the study by Bishop and Chamberlain (1989). In this second part of our work, we present here the density profiles of atomic Hydrogen in planetary exospheres subject to the radiation pressure. We first provide the altitude profiles of ballistic particles (the dominant exospheric population in most cases), which exhibit strong asymmetries that explain the known geotail phenomenon at Earth. The radiation pressure strongly enhances the densities compared with the pure gravity case (i.e. the Chamberlain profiles), in particular at noon and midnight. We finally show the existence of an exopause that appears naturally as the external limit for bounded particles, above which all particles are escaping.
Date Issued
2015-09-02
Date Acceptance
2015-08-12
Citation
Icarus, 2015, 266, pp.423-432
ISSN
1090-2643
Publisher
Elsevier
Start Page
423
End Page
432
Journal / Book Title
Icarus
Volume
266
Copyright Statement
© 2015 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/).
(http://creativecommons.org/licenses/by/4.0/).
License URL
Subjects
Astronomy & Astrophysics
0201 Astronomical And Space Sciences
0402 Geochemistry
0404 Geophysics
Publication Status
Published