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

这项提议将详细研究小型太阳系天体多孔次表层中的物理过程。这个项目源于几次彗星空间飞行任务的结果和我们实验室实验的结果，这些实验阐明了在与在彗星表面观察到的物理条件相匹配的物理条件下，多孔、尘埃和结冰介质中的传输过程。在这个项目中，我们将开发一种新的模块化计算机模型，用于研究多孔尘埃-冰面层中的能量和质量传输。我们的模型将包括：i)对均匀和非均质颗粒样品的全新微观物理描述，ii)基于离散和连续方法对这种不同介质中的瞬变质量和能量传递的新的多维自洽处理，以及iii)尘埃-冰孔混合物演化的新的微观物理模型。最近和即将进行的实验室实验的结果将用于开发和验证新的计算机模型。我们方法的优势在于(I)使用创新的补充方法来进行计算机模拟，从微观到介观，以及(Ii)理论工作和实验工作的密切联系，这将显著提高计算机模型的可靠性和适用性。因此，我们将获得强大的理论工具，使我们能够研究与彗星次表面区域的瞬时交换过程有关的广泛问题。我们打算模拟导致观测到的核表面的高温及其极低的热惯性、挥发分和非挥发分的持续释放、彗星表面的粒子抛射过程及其演变为内部彗星的物理过程。随着欧洲航天局的罗塞塔号航天器抵达67P/丘留莫夫-格拉西缅科彗星，来自21个实验的独特科学数据正在变得可用。这些将第一次以足够的分辨率对彗星进行详细研究，以研究彗星物理学中的基本开放问题。需要解决的关键核心问题是彗星活动是如何运作的，以及是什么驱动了它。根据多年的现场经验，我们相信该项目将产生显著的效果。

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.