The numerical analysis of surface-bounded exospheres in our solar system, with a particular focus on the Moon, is an intriguing field of research that sheds light on the complex interactions between celestial bodies and their surrounding atmospheres. This research investigates various aspects, such as the composition, structure, and dynamics of exospheres and the influence of external factors like solar radiation and the magnetic field. Numerical models and simulations play a crucial role in understanding the behavior and evolution of these exospheric systems. By incorporating physical principles and observational data, these models allow researchers to study phenomena like outgassing and sputtering. The knowledge gained from these numerical analyses contributes to our comprehension of the Moon's exosphere, aiding future space missions and facilitating comparisons with other celestial bodies within our solar system.

ExESS is both the name of the research project, as well as the name of the research code collection developed at the Professorship of Lunar and Planetary Exploration Technologies, written in the open-source and high-performance language Julia. It acts as a numerical foundation to set up a wide variety of scientific simulations of exospheres and their exobases, i.e., their respective surfaces. Students interested in the topic can engage both in the development of the code collection as well as in the scientific investigations by applying the code to relevant research questions.

A non-exhaustive list of current research topics includes:

• investigation of velocity distributions of various exospheric species, including their height dependence (numerical/theoretical/analytical)
• comparison to observational data, especially from LADEE (numerical/data analysis)
• development of ground-based and satellite measurement models, converting heigh-dependent exospheric densities into mass-spectrometer count measurements or spectral line-of-sight column densities (numerical/theoretical)
• development of a surface reaction kinetics model, focussing on the interaction of the surface with solar wind particles as well as the formation of hydrogen, hydroxyl, and water (numerical/theoretical/analytical)
• investigation of energy and velocity distributions of photodissociated particles (numerical/theoretical)
• development of a lunar topography model to estimate a distribution of slopes at various scales (numerical/theoretical)

Code development topics include:

• statistical estimation of Monte-Carlo simulation requirements (numerical/theoretical)
• comprehensive grid studies based on various different numerical discretization schemes (numerical)
• investigating the possibility and benefit of implementing a GPU-based version of the code (numerical)

If you are interested in one of the topics listed above, or if you have your own idea for a thesis based on the presented project, feel free to contact me. I am happy to discuss your ideas and find a suitable topic for you. The thesis is suitable for students with a background in engineering, physics, mathematics, or computer science. A basic understanding of numerical methods and programming is required.

More Information:

• ExESS
• Julia Language: https://julialang.org