Exploring the lunar neutral corona

Solar wind particles impinging surfaces of airless bodies resulting in ion sputtering. Released atoms have energies from few up to 100 eV.

They exceed escape energies, are weakly gravitationally bound and form planetary coronae, vast gaseous envelopes extending several 10,000’s km away from the central body.

Studying coronae, their dynamics and dependence on the external factors driving them is the key to understanding exospheres, solar wind – surface interactions at airless bodies and how corona affect their environment.

The main science questions the project will answer:How does ion sputtering form the extended lunar corona?How does the lunar corona supply material to the terrestrial magnetosphere?Since January 2019, the IRF-built and SNSA-supported Advanced Small Analyzer for Neutrals (ASAN) on the Chinese lunar rover Yutu-2 of the Chang’E-4 mission provides mass resolving measurements of neutral atoms released from the lunar surface.

ASAN for the first time measured spectra and fluxes of heavy (O, Si-group, Fe-group) sputtered energetic neutral atoms.

Using ASAN data as ground truth, orbital data available from the Chandrayaan-1 mission and Direct Simulation Monte Carlo (DSMC) parallel codes available in our group, we will build a consistent model of the sputtered lunar corona and investigate its dependency on solar wind conditions.

The study will also assess the impact of the lunar corona on its environment, e.g. the terrestrial magnetosphere.The project is unique in the scope and idea to combine the first-ever measurements of sputtered neutral atoms on the lunar surface, publicly available data from measurements in lunar orbit and state-of-the-art numerical models available in our group.

The ASAN data recently became public and IRF is in the competition to fully explore the data set first to return IRF’s and SNSA’s investments to the project.We apply for a two-year postdoc position located at IRF in Kiruna to perform data analysis and modelling.