Atmospheric Erosion for the Terrestrial Planets: A Semi-Empirical Model
Maria Luisa Alonso Tagle 1,2 , Romain Maggiolo 2 , Herbert Gunell 3 , Johan De Keyser 1,2 , Gaël
Cessateur 2 , Giovanni Lapenta 1 , Viviane Pierrard 2 and Ann Carine Vandaele 2
(1)Katholieke
Universiteit Leuven, Department of Mathematics, Leuven, Belgium
(2)Belgian Institute for
Space Aeronomy, Brussels, Belgium
(3)Umeå University, Department of Physics, Umeå, Sweden
Abstract Text:
A large-scale planetary magnetic field was long thought, to protect planetary atmospheres from escaping into interplanetary space. However, this paradigm has been challenged during the last years. In this study, we present the latest development of a semi–empirical model, that describes the atmospheric escape of Venus-like, Earth-like and Mars-like planets, as a function of their planetary magnetic moment and of the solar wind dynamic pressure. The main objective of this model is to reproduce early planetary and solar conditions, in order to: firstly bind relate the planetary magnetic field and solar wind pressure to atmospheric loss; and secondly constrain it over geological time scales.
We show that atmospheric escape rate is particularly high for weakly magnetized planets and high solar wind pressure levels. In this regime, atmospheric loss is dominated by ion escape from the polar regions and it is mostly limited by the ion production at the ionospheric level. We will discuss potential implications of these results, on atmospheric escape around rocky planets in the early solar system, when the Sun was more active and its solar wind was more intense.
Session Selection:
P023. Planetary Atmospheres, Space Weather, and Magnetic Fields: A Joint AGU-AAS
