Space Studies of the Upper Atmospheres of the Earth and Planets including Reference Atmo-
spheres (C)
Planetary Upper Atmospheres, Ionospheres and Magnetospheres (C3.2)
Consider as poster only.
A SEMI-EMPIRICAL MODEL OF THE DEPENDENCY OF ATMOSPHERIC
ESCAPE ON THE PLANETARY MAGNETIC MOMENT
Mrs. Maria Luisa Alonso Tagle (BIRA-IASB, Brussels, Belgium)
Romain Maggiolo (BIRA-IASB, Brussels, Belgium)
Herbert Gunell (Umeå University, Umeå, Sweden)
Gäel Cessateur (BIRA-IASB, Brussels, Belgium)
Johan De Keyser (BIRA-IASB, Brussels, Belgium)
Giovanni Lapenta (Centre for Plasma Astrophysics - KU Leuven, Leuven, Belgium)
Viviane Pierrard (BIRA-IASB, Brussels, Belgium)
Ann C. Vandaele (BIRA-IASB, Brussels, Belgium)
The role of the planetary magnetic field in the longevity of planetary atmospheres remains debated. Several recent studies suggest that magnetization does not necessarily protect atmospheric material from escaping into space. In this context, Gunell et al. (2018, doi:10.1051/0004-6361/201832934) developed a semi-empirical model for Venus-, Earth- and Mars-like planets. This model uses in-situ measurements and physical considerations to model the effect of planetary magnetization on the atmospheric loss rate. It shows that atmospheric loss rate can be higher for magnetized planets than unmagnetized ones over a wide range of magnetic moments for current solar and atmospheric parameters. We further develop this model in order to vary other parameters that drive atmospheric erosion, for example solar wind pressure or solar EUV radiation. The main objective is to reproduce early planetary and solar conditions in order to constrain the role of the planetary magnetic field on atmospheric loss over geological time scales. We summarize previous results, describe the semi-empirical model, and discuss its future development. We show results illustrating how the model can be used to study the past evolution of the atmosphere of the rocky planets in the Solar System. We are particularly interested in the peaks of the erosion rate and its possibility of occurrence in the past.
