Energy and mass transport in porous icy and dusty media. Microphysical simulations and applications to comets

• Applicant: Dr. Yuri Skorov
• Subject Area: Geophysics
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 285787948

This proposal will investigate in detail the physical processes in the porous sub-surface layers of small Solar System bodies. This project stems from results of several space missions to comets and results of our laboratory experiments elucidating the transport processes inside porous dusty and icy media under the physical conditions matching those observed at the surfaces of comets. In this project we will develop a novel modular computer model of transport of energy and mass in porous dust-ice surface layers. Our model will consist of i) an entirely new microphysical description of granular samples, both homogeneous and heterogeneous, ii) new multidimensional self-consistent treatments of the transient mass and energy transfer in such varied media, based on discrete and continuum approaches, and iii) a new microphysical model of the evolution of the dust-ice porous mixture. The results of recent and forthcoming laboratory experiments will be used to develop and verify novel computer models. The strength of our approach lies in the (i) use of innovative complementary approaches to computer simulations, from microscopic to mesoscopic scale, and (ii) close relationship of theoretical and experimental works, which will significantly enhance the reliability and applicability of the computer models. As a result, we will get powerful theoretical tools that will allow us to investigate a wide range of problems concerning transient exchange processes in the sub-surface regions of comets. We intend to model the physical processes leading to the observed high temperature of the nucleus surface and its extremely low thermal inertia, the persistent release of volatiles as well as of non-volatiles, the particle ejection process from the cometary surface and its evolution into the inner cometary coma. With the arrival of the European Space Agency's Rosetta spacecraft at the comet 67P/Churyumov-Gerasimenko, unique scientific data from 21 experiments are becoming available. These will, for the first time, allow a detailed study of a comet in sufficient resolution to investigate the fundamental open questions in cometary physics. The key central question to be addressed is how cometary activity works and what drives it. Based on many years experience in the field, we believe that the project will deliver prominent results.

• DFG Programme: Research Grants