Geophysical Investigations of Mars and Mercury

我的研究重点是地球物理调查类地行星，卫星和小天体在我们的太阳系。拟议的研究计划主要旨在利用最近太空任务返回的数据，以解决与火星和水星的历史和现状相关的关键知识差距。这些研究的共同点是观测到的磁场对行星内部结构和演变以及对大气和磁层过程的基本限制。在水星和火星，磁场来自“内部来源”，如金属核心中的流体运动和/或地壳岩石的磁化，以及“外部来源”，如在行星表面上方产生的电流系统。由此产生的环境提供了关于每个行星内部的基本线索，在高层大气和行星周围的空间环境中发生的过程，以及这些内部和外部过程如何相互作用以塑造行星的演变。 我们将利用信使使命（2011-2015）的轨道数据调查水星地壳磁场的性质和历史。对地壳磁场的研究将阐明地壳中磁化的分布和起源以及地核发电机的历史。拟议计划的一个新方面是量化与一些陨石坑相关的增强磁化是否反映了撞击产生的铁增强。这可以提供一种创新的方式来限制水星上的撞击物数量：即含铁撞击物与不含铁撞击物的相对比例。我们还将开发水星的热演化模型，这是非常积极的挑战，满足三个限制水星的早期演化：广泛的早期喷发火山活动，大量的行星收缩和发电机。 对火星的研究旨在了解火星表面磁场时间变化的性质和起源，这是InSight着陆器首次在火星上测量（2018年12月至今）。我们将利用这些数据，以及MAVEN使命（2014年11月至今）的卫星观测，来探测行星内部的电导率结构，这反过来又与内部温度，成分和挥发性含量有关。另一个方面涉及使用地壳场模型，表面地质和撞击坑的记录来阐明火星发电机的历史以及地壳磁化的深度。 拟议的研究计划是一个关键的，实用的方法来调查重要的物理过程，管理我们自己和其他太阳系行星的演变。获得资助的人员将为国际行星飞行任务做出贡献，并接受行星物理学、计算和数据分析方面的高级培训，为他们在学术界、政府或私营企业获得广泛机会做好准备。

My research focuses on geophysical investigations of terrestrial planets, moons and small bodies in our solar system. The proposed research program is broadly aimed at exploiting data returned from recent space missions to address key knowledge gaps related to the histories and current states of Mars and Mercury. Common to the investigations are fundamental constraints offered by observed magnetic fields on planetary interior structure and evolution, as well as on atmospheric and magnetospheric processes. At Mercury and Mars, magnetic fields arise from "internal sources" such as fluid motions in the metallic core and/or magnetization of crustal rocks, and from "external sources" such as current systems generated high above the planet's surface. The resulting environments provide fundamental clues about each planet's interior, processes occurring in the upper atmosphere and the space environment around the planet, and how these internal and external processes interact to shape a planet's evolution. We will investigate the nature and history of Mercury's crustal magnetic field using orbital data from the MESSENGER mission (2011-2015). Investigations of crustal magnetic fields will elucidate the distribution and origin of magnetization in the crust and the history of the core dynamo. A novel aspect of the proposed program is to quantify whether enhanced magnetizations associated with some craters reflect impact-delivered iron enhancements. This can provide an innovative way to constrain the impactor population at Mercury: namely, the relative proportions of iron-bearing versus iron-free impactors. We will also develop thermal evolution models for Mercury, that are critically motivated by the challenge of satisfying three constraints on Mercury's early evolution: extensive early effusive volcanism, substantial planetary contraction and a dynamo. Studies of Mars aim to understand the nature and origin of time variations in the Martian surface magnetic field, measured for the first time by the InSight lander on Mars (Dec. 2018 - present). We will use these data, together with satellite observations from the MAVEN mission (Nov. 2014 - present), to probe the planet's interior electrical conductivity structure, that in turn is related to interior temperature, composition and volatile content. A further aspect involves using crustal field models, surface geology and the record of impact craters to elucidate the history of the Martian dynamo as well as the depths of crustal magnetization. The proposed research program is a key, practical approach to investigating important physical processes that govern the evolution of planets in our own and other solar systems. Funded personnel will contribute to international planetary missions and receive high-level training in planetary physics, computing and data analysis, preparing them for a broad range of opportunities in academia, government or private industry.