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

该提案将详细研究太阳系小天体多孔亚表层的物理过程。这个项目源于几次彗星太空任务的结果，以及我们实验室实验的结果，这些实验阐明了多孔尘埃和冰介质中在与彗星表面观测到的物理条件相匹配的物理条件下的传输过程。在这个项目中，我们将开发一种新的模块化计算机模型，用于模拟多孔尘冰表层的能量和质量传输。我们的模型将包括i)一个全新的颗粒状样品的微物理描述，包括均匀的和非均匀的；ii)基于离散和连续方法的新的多维自一致处理，在这种不同的介质中瞬态质量和能量传递；iii)一个新的微物理模型，用于研究粉尘-冰多孔混合物的演化。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。我们的方法的优势在于(i)使用创新的互补方法来进行计算机模拟，从微观到中观尺度；（ii）理论和实验工作的密切联系，这将大大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，使我们能够研究有关彗星亚表面区域瞬态交换过程的广泛问题。我们打算模拟导致观察到的核表面高温和极低热惯性的物理过程，挥发性物质和非挥发性物质的持续释放，彗星表面的粒子喷射过程及其向彗星内部昏迷的演变。随着欧洲航天局的罗塞塔号宇宙飞船抵达彗星67P/Churyumov-Gerasimenko，来自21个实验的独特科学数据变得可用。这将首次使人们能够以足够的分辨率对彗星进行详细的研究，从而研究彗星物理学中基本的开放性问题。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。基于该领域多年的经验，我们相信该项目将取得显著成果。

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.