Scaling atmospheric ion escape to IMF orientation and planet magnetic dipole strength in terrestrial worlds

Understanding the mechanism and rate of atmospheric escape is crucial in assessing a planet's habitability. Many simulations have accurately reproduced the observed rate of atmospheric loss from worlds in our solar system, but these simulations apply only to the planet for which they're designed. Generic scaling laws are difficult to reliably extrapolate from such a small dataset. This project models atmospheric loss of ions on a generic Mars-like terrestrial planet. More generally, we examine how the stellar wind and interplanetary magnetic field (IMF) interact with the planet's intrinsic magnetic dipole and affect ion atmospheric loss.

This project will use the open-source hybrid plasma model RHybrid (developed at the Finnish Meteorological Institute) to simulate atmospheric escape of O₂⁺, O⁺, and H⁺ ions from a planet with a weak dipole magnetic field. The magnetic dipole of the planet is oriented perpendicular to the stellar wind and the model will be run with different magnetic dipole strengths and an array of IMF orientations that vary with respect to the planet's magnetic dipole. The results from these simulations will be analyzed and compared to quantify the dependence of the ion loss rate on IMF orientation. These results will also be used to understand the ion loss processes that occur through the interaction between the planetary magnetic field and IMF.