The Aeroplanets Model: Investigating the Excitation and Ionization of Gas Species in the Upper Atmosphere of Planets

The Aeroplanets model (Gronoff et al. 2012) facilitates investigation of the importance of ionization and excitation of gas species in determining the vertical distribution of electrons in the upper atmosphere of Planetary and Exoplanetary systems. The Aeroplanets model is uniquely designed for this with a code that is robust enough to handle the computations while being flexible enough to adapt to different atmospheric species and conditions. The model has a modular design that allows the user to easily isolate and test the effects of particle precipitation (e.g. protons, electrons, hydrogen atoms) and extreme ultraviolet (XUV) radiation on the ionization and excitation of the different gas species. Included with the model is a database, the Atomic and Molecular Cross-section for Ionization/Airglow database (ATMOCIAD) (https://doi.org/10.5281/zenodo.4632426). This database contains the cross sections for neutral atoms, neutral molecules, and ions at low energy (keV to MeV) necessary to model the vertical distribution of thermal and suprathermal electrons in a planetary atmosphere. Uncertainty values are also included (when available) to consider uncertainty in reported cross section values. We highlight the use of the Aeroplanets model with features of the vertical structure in the upper atmosphere of Venus that exist in observations, such as those from the Pioneer Venus Orbiter.