New compound and hybrid binding energy sputter model for modeling purposes in agreement with experimental data

• Main Authors: Jäggi, Noah, Mutzke, Andreas, Biber, Herbert, Brötzner, Johannes, Szabo, Paul Stefan, Aumayr, Friedrich, Wurz, Peter, Galli, André
• Format: Journal Article
• Language: English
• Published: 24-04-2023
• Subjects: Physics - Earth and Planetary Astrophysics; Physics - Instrumentation and Methods for Astrophysics; Physics - Space Physics
• DOI: 10.48550/arxiv.2304.12048

Rocky planets and moons experiencing solar wind sputtering are continuously
supplying their enveloping exosphere with ejected neutral atoms. To understand
the quantity and properties of the ejecta, well established Binary Collision
Approximation Monte Carlo codes like TRIM with default settings are used
predominantly. Improved models such as SDTrimSP have come forward and together
with new experimental data the underlying assumptions have been challenged. We
introduce a hybrid model, combining the previous surface binding approach with
a new bulk binding model akin to Hofs\"ass & Stegmaier (2023). In addition, we
expand the model implementation by distinguishing between free and bound
components sourced from mineral compounds such as oxides or sulfides. The use
of oxides and sulfides also enables the correct setting of the mass densities
of minerals, which was previously limited to the manual setting of individual
atomic densities of elements. All of the energies and densities used are
thereby based on tabulated data, so that only minimal user input and no fitting
of parameters are required. We found unprecedented agreement between the newly
implemented hybrid model and previously published sputter yields for incidence
angles up to 45{\deg} from surface normal. Good agreement is found for the
angular distribution of mass sputtered from enstatite MgSiO$_3$ compared to
latest experimental data. Energy distributions recreate trends of experimental
data of oxidized metals. Similar trends are to be expected from future mineral
experimental data. The model thus serves its purpose of widespread
applicability and ease of use for modelers of rocky body exospheres.