Escape of planetary atmospheres: physical processes and numerical models
M.Ya. Marovb aInstitute of Astronomy, Russian Academy of Sciences, ul. Pyatnitskaya 48, Moscow, 119017, Russian Federation bV.I. Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Kosygina str. 19, Moscow, 119991, Russian Federation
In addressing the problem of the dissipation (escape) of planetary atmospheres, this paper discusses the physical mechanisms controlling the nature of the occurring processes and reviews the mathematical models and numerical methods used in the analysis of this phenomenon taking into account the limitations imposed by available experimental data. Structural and dynamic features of the aeronomy of the Earth and terrestrial planets are discussed in detail that are key in determining the energy absorption rate and the atmospheric escape rate. A kinetic Monte Carlo method developed by the authors for investigating the thermal and nonthermal processes of atmospheric escape is presented. Using this approach and spacecraft data, atomic loss rates from the Venusian and Martian atmospheres through a variety of escape processes are estimated, and their role at the current and early evolutionary stages of these planets is discussed. The discovery of exosolar planets, the model studies of the dissipation of their gas envelopes, and the likely impact of the dissipation mechanisms on the planetary atmosphere and climate evolution stimulated the field reviewed and made it a subject of current topical interest.
Keywords: planetary atmosphere, aeronomy, modeling, suprathermal atoms, thermal and nonthermal escape processes, kinetic Monte Carlo method PACS:02.70.−c, 92.60.−e, 96.30.Ea, 96.30.Gc (all) DOI:10.3367/UFNe.2017.09.038212 URL: https://ufn.ru/en/articles/2018/3/a/ Citation: Shematovich V I, Marov M Ya "Escape of planetary atmospheres: physical processes and numerical models" Phys. Usp.61 217–246 (2018)